Air pollution

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Air pollution has been a public health problem since the discovery of fire. In ancient times, people lit fires in their caves and huts and often polluted the air with noxious smoke. The Roman philosopher Seneca wrote about the "heavy air of Rome in 61 BC and in the eleventh century banned the burning of coal in London.
The origin of our modern problems of air pollution can be traced to eighteenth-century England and the birth of the industrial revolution. Industrialization began replacing agricultural activities and people moved from countryside to city. The factories needed to produce energy by burning fossil fuels such as coal and oil.
The main air pollution problem in the late nineteenth and early twentieth century was the smoke and ash produced by burning fossil fuels in stationary power plants. The situation worsened with the increasing use of cars. Over time, there were important public health events due to air pollution in cities like London, England and Los Angeles in the United States.
The smoke and ash produced in power plants contributed to air pollution in the late nineteenth and early twentieth century. Since 1957, following a conference in Milan on public health issues related to air pollution in Europe The World Health Organization (WHO) has been concerned about this issue, especially its effects on health.


The air we breathe is made up of many chemical components. The primary components of air are nitrogen (N 2), oxygen (O 2) and water vapor (H 2 0). In the air are also small amounts of many other substances, including carbon dioxide, argon, neon, helium, hydrogen and methane.
ImageThe primary components of air are: - Nitrogen - Oxygen - Water Vapor
Human activities have had a detrimental effect on the composition of air. The burning of fossil fuels and other industrial activities have changed their composition due to the introduction of pollutants, including sulfur dioxide (SO2), carbon monoxide (CO), volatile organic compounds (VOCs), nitrogen oxides (NO x ) and solid and liquid particles known as particulate matter. Although these contaminants can be generated by natural sources, human activities have significantly increased their presence in the air we breathe.
Air pollutants can have an effect on the health and welfare of human beings. An effect is defined as an observable or measurable adverse change due to an air pollutant. A contaminant can affect the health of humans and the plants and animals. The contaminants can also affect non-living materials such as paints, metals and fabrics.
Health effects - affects the health of peopleWelfare effects - disrupted life and reduces living standards.

How air pollution affects our health
Air pollution has a direct effect on human health. In extreme cases, has caused deaths as a result of the combination of geographical features unusual climatic factors. For example, the air pollution episode in Donora, Pennsylvania in the United States in 1948 caused 20 deaths and more than 5,000 patients. This is an example of the serious adverse effects resulting from the excess of population and industry, together with geographical and meteorological factors in a concentrated area.
The excess of population and industry, together with geographical and meteorological factors can create serious air pollution problems. Exposure to air pollutants can cause acute (short term) and chronic (long term) health. Usually, acute effects are immediate and reversible upon cessation of exposure to the contaminant. The most common acute eye irritation, headache and nausea. Sometimes slow onset chronic effects, last indefinitely and tend to be irreversible. The chronic health effects include decreased lung capacity and lung cancer due to a prolonged period of exposure to toxic air pollutants such as asbestos and beryllium.

Acute Health Effects - Immediate - short term - often reversibles.Efectos chronic health - long term - often irreversible.
The respiratory system and air pollution
While pollutants can affect the skin, eyes and other body systems, the main respiratory system is damaged. The following figures show the components of this system. The air is inhaled through the nose that acts as the body's primary filtering system.
The small hairs and the hot and humid conditions of the nose effectively remove contaminant particles larger. Then the air passes through the pharynx and larynx before reaching the top of the trachea. The trachea divides into two parts, left and right bronchi. Each bronchus subdivides into ever smaller compartments called bronchioles that contain millions of air sacs called alveoli. The bronchioles and alveoli, are the lungs.
Air pollutants, both gaseous and particulate, can have negative effects on the lungs. The solid particles can permeate the walls of the trachea, bronchi and bronchioles. Most of these particles are removed from the lungs through the action of cleaning (sweep) of the cilia, tiny hairs in the lining of the lungs. This is what happens when you cough or sneeze.

A cough or sneeze particles transported to the mouth. The particles are removed when ingested or expelled from the body. However, extremely small particles can reach the alveoli, where it often takes weeks, months or even years for the body to remove them.

It is difficult for the lungs to remove extremely small particles.
Gaseous air pollutants can also affect lung function by reducing the action of the cilia. Continuously breathing polluted air decreases the normal cleaning function of the lungs, which can cause large number of particles reaching the lower parts of the lung.
The lungs are the organs responsible for absorbing oxygen from the air and remove carbon dioxide from the bloodstream. The damage to the lungs from air pollution can inhibit this process and contribute to the occurrence of respiratory illnesses like bronchitis, emphysema and cancer. It can also affect the heart and circulatory system.


Air pollution occurs in both external (environmental) and internal. The effects of air pollution on health varies greatly from person to person. Those most affected by air pollution are the elderly, infants, pregnant women and chronically ill lung and heart. People who exercise outdoors are also susceptible because they breathe more rapidly and deeply, allowing the entry of more pollutants into the lungs. Runners and cyclists who exercise in areas of high traffic may be causing more harm than good.
Photochemical smog (photochemical smog) is a term of air pollution that is used daily. In fact, photochemical smog is ground-level ozone formed by the reaction of pollutants with sunlight. The figure below shows the factors involved in the creation of photochemical smog. This has a detrimental effect on health of high risk groups mentioned above. In Mexico City, Santiago and Sao Paulo, for example, newspapers and radio stations report daily levels of air quality to alert those at risk who are outdoors. These indices are a measure of the levels of pollutants and airborne particles.
Indirect effects of air pollution
The ever increasing possibility of getting skin cancer is an indirect effect of air pollution on health. Although ozone in the lower atmosphere is harmful to the environment in the upper atmosphere is necessary to protect the Earth from damaging ultraviolet radiation.
This protective layer is being damaged due to the massive discharge of chlorofluorocarbons (CFCs) in the atmosphere. CFCs are commonly used in refrigerators and air conditioners as gas and aerosol sprays.
Indoor Air Pollution
The effects of indoor air pollution have received increased attention in recent years because that is where people spend almost 90 percent of his time. Several studies have shown that exposure to some pollutants can be two to five times higher indoors than outdoors. There are many types of indoor pollutants, such as smoke from artifacts, fireplaces and cigarettes organic pollutants in paints, dyes, cleaners and building materials and radon.

ImageExposure to some pollutants can be two to five times higher indoors than outdoors. Radon is a gas that occurs naturally, is odorless and colorless and is radioactive. Its effects on human health are important because it is the second factor, after smoking, which causes lung cancer. Fortunately, radon levels can be reduced air circulation and ventilation.

Indoor pollutants and main sources:
ContaminantePrincipales sourcesQUIMICOSNOxEstufas COMPOUNDS paraffin, gas stoves, etc.COHTA, heating and cooking fuel, paraffin infiltration exterioresSO2Estufas, wood or gas heaters, etc.O3Fotocopiadoras, laser printers, ozonator, infiltration of exterior building etc.COV5Materiales ( adhesives, paneling, insulation, etc..), hypertension, gas furnaces, air conditioning, outdoor infiltration, paraffin heaters, cleaners, construction etc.FibrasMateriales, policiclicosCombustibles aromatic etc.Hidrocarburos heating and cooking, HTA infiltration external etc.MetalesPinturas (Pb) batteries (Pb, Cd), PVC (Cd), electrical (Hg), dry outer etc.PesticidasUso of termiticides, insecticides, fungicidasMaterial particuladoCombustión indoor ETS infiltration external ambientalCombustión of etc.Humo of snuff tabacoAGENTES FISICOSRadiacionesArtefactos eléctricosCalorSistemas combustion and artifacts eléctricosAGENTES BIOLOGICOSBacterias Virus HongosSistemas air conditioning, pets, houseplants, standing water, etc. in the lesson four is discussed in detail the effects of air pollutants common or "standard" and some dangerous health. The criteria pollutants are those for which standards have been established national air quality. The criteria pollutants are carbon monoxide, ozone, sulfur oxides, particulate matter, nitrogen oxides and lead. Hazardous contaminants include volatile organic compounds, asbestos, vinyl chloride and mercury, among others.
How air pollution affects other aspects of our lives
Air pollution has a detrimental effect on almost every phase of our lives. Besides the health effects discussed above, many other side effects on vegetation, soil, water, materials made by man, weather and visibility.
Since 1970 he has studied the effects of air pollution on crops, trees and other vegetation. Field investigations and greenhouse experiments have shown that ozone is toxic to plants and can destroy crops varied.
ImageOzone is toxic to plants. Likewise, acid rain affects crops such as oats, alfalfa, peas and carrots, and forest areas. There is evidence that increased ultraviolet radiation due to ozone loss in the upper atmosphere is affecting the normal growth cycle of plants.
Acid Rain

Acid rain has received much attention at the international level. It is formed when air pollutants such as sulfur dioxide (SO2) and nitrogen oxides (NO x) are transformed into acids in the atmosphere. Subsequently, the resulting precipitation (rain, snow or fog) the fatty deposits in lakes and soils. The acid rain control has become an international concern, since often the source of these pollutants is far from the place where the effects are recorded.

Acid rain can destroy or harm wildlife in lakes and streams and also man-made buildings. Research has indicated that acid rain can destroy or harm wildlife in lakes and streams, and buildings made by the man, such as buildings and outdoor monuments. The statues of ancient Greece and Italy have been significantly damaged by acid rain.
Air pollution also affects visibility. This has led to problems related to the safety of aircraft operations and destruction of natural landscapes. For example, the visibility of the Grand Canyon in the United States has been affected by air pollution generated by man for hundreds of miles away.
Air pollution can cause problems related to flight safety.
Global warming
There is evidence that air pollution contributes to global warming or the greenhouse effect. The burning of fossil fuels emits too much carbon dioxide into the atmosphere. Normally, carbon dioxide is not dangerous because it is a necessary nutrient for plants, but the amount produced is much greater than that required by vegetation.
ImageThe greenhouse effect occurs because carbon dioxide forms a blanket over the surface of the earth and traps heat reflected from the soil carbon dioxide forms a blanket over the surface of the earth and traps heat reflected from the ground. The effect is similar to a closed automobile or a greenhouse, hence the term greenhouse. Scientists are predicting that in the next fifty years, global warming could raise the temperature three to nine years longer than current averages. This would result in drastic changes in climate worldwide.
As we have seen, air pollution affects our lives in many ways. Primary sources of air pollution are factories and modern conveniences we rely on for economic growth and lifestyle. Balancing economic development with the need to protect the public from the risks of air pollution on health and wellness is a challenge that countries face. To illustrate this challenge, the next chapter describes the efforts undertaken in the United States and Chile.

III: Origins of modern regulations of air pollution

We sometimes have the misconception that attempts to regulate air pollution began in the last decades. In fact, the various air pollution laws have existed since at least a century ago. What is new is the widespread public awareness about the serious threat posed by air pollution to health and the leadership role that governments have assumed control. The concern over this issue has led to the development of more comprehensive legislation to manage the control of air pollution today. This lesson points out the main points of these laws and provides a brief background of the control of air pollution.
Comparing the efforts to control air pollution with water, laws and regulations protecting water supplies were enacted long before, as since the Middle Ages recognized the effects of water pollution on human health humans.
Initially it was thought that air pollution was more a nuisance than a threat to human health. However, and in 1306 he passed some laws to prevent air pollution. That same year, Edward I of England banned the burning of coal in the ovens of artisans because of foul gases. Centuries later, Elizabeth I banned for aesthetic reasons like the burning of coal in London while Parliament was in session.
Over the years, worsened air pollution, but is not yet widely recognized as a threat to human health. Although some scientists and physicians perceived air pollution as a public health problem, early control efforts related to the aesthetic effects or the welfare of people. In the late nineteenth and early twentieth centuries, many ordinances were enacted to control smoke in England and America. These provisions were first enacted laws to control air pollution.
The delay in recognizing air pollution as a health risk was partly due to the nature of pollution, because it is not as obvious as that of water. It can therefore be ignored as a health threat until the problem reaches crisis proportions. This was the case in air pollution episodes in Meuse Valley, Belgium in 1930, in Donora, Pennsylvania, in 1948 and in London, England, in 1952. The conditions in these places arose progressively worsened until serious consequences on public health. These and other similar episodes, which helped prove that air pollution affects health, were the incentive to establish more stringent laws to control pollution.

Efforts to control air pollution in the U.S.
Initially, municipal governments are responsible for approving and enforcing legislation on the control of air pollution. Then in the 1950s, the federal government of the United States began efforts to control air pollution by adopting the Law on the Control of Air Pollution 1955. This was the first federal air pollution and federal programs established to investigate the effects of air pollution on health and wellness. It also authorized the federal government to provide technical assistance to state governments. In 1963 and 1965 additional laws were passed.
The Clean Air Act of 1970
The adoption of the Clean Air Act of 1970 marked the beginning of modern efforts to control air pollution in the United States. This law coincided with the formation of the EPA (Environmental Protection Agenecy - EPA), which established a change in U.S. policy regarding the control of air pollution.
While the federal government had previously been primarily an educational and advisory, the new EPA emphasized strict adherence to the laws that prevented air pollution.
National quality standards and ambient air criteria pollutants
The bounding aspect of the 1970 amendments was the establishment of a managerial approach for managing air quality based on the adoption of national standards for air quality (NNCAE). These standards limit the concentration of pollutants that endanger public health or welfare and are in outdoor environments.
Initially, NNCAE were established for six pollutants:
· Particulate
· Sulfur dioxide
· Nitrogen dioxide
· Carbon monoxide
· Photochemical oxidants
· Non-methane hydrocarbons
These pollutants are called criteria pollutants because standards were based on documents on air quality criteria. The list of criteria pollutants was subsequently changed.
For each pollutant criteria established primary and secondary rules. The primaries were set at levels that protect public health and secondary standards were set at protecting the public welfare. EPA established the technical basis for standards documents air quality criteria.
Specific measures to control air pollution have started to NNCAE as tangible goals. These actions included the establishment of quantifiable emission limits to meet NNCAE and developing a system to ensure compliance with these limits
Performance standards for stationary and mobile sources
The Clean Air Act of 1970 established ambitious targets for mobile and stationary sources of air pollution. The new law required that by 1975 automakers reduce 90% of the emission of pollutants from new vehicles. It set specific limits for emissions of carbon monoxide, hydrocarbons and nitrogen oxides. This forced the automotive industry to develop new technologies for emission control.
The Clean Air Act of 1970 required that new vehicles would reduce 90% of the emission of pollutants by 1975. Implementation Plans of the states
Another main requirement of the 1970 Act was that each state submit an implementation plan to EPA. These plans, which are still in place, outlining steps to be followed to meet air quality standards. Each state was required to establish control regions air quality (RCCA) in all geographical areas of the state. The EPA must approve the implementation plan before the state is prepared to enforce the plan.
Another main requirement of the 1970 Act was that each state submit an implementation plan to EPA national standards for issuance of hazardous air pollutants
The Clean Air Act of 1970 also required the EPA to regulate toxic pollutants or hazardous air. The regulations are called national standards for the emission of hazardous air pollutants (NNECPA). The law required the EPA to determine the rules by a wide margin of safety to protect public health given the risk of these pollutants. To date, have been established for eight NNECPA toxic air pollutants:
· Beryllium
· Mercury
· Vinyl chloride
· Benzene
· Radionuclides
· Arsenic
· Asbestos
· Radon
Guidelines for the control
Another requirement of the Clean Air Act of 1970 for the EPA was providing technical assistance to states to support their implementation plans. In a support program, EPA establishes guidelines for control of air pollutants emitted by specific industries. The guidelines provide states information on existing technologies for control, referred to as reasonably available control technology (TCRD). The TCRD represents control techniques commonly in use in a specific industry.
Prevention of significant deterioration and review of new sources of pollution
The Clean Air Act 1970 was amended in 1977. One notable change was the concept of prevention of significant deterioration (PDS) as a result of a sensational court case that required the EPA to publish regulations to prevent "degradation" of air in areas where it is cleaner than required by national rules environmental air quality. Another outcome of this case was that the EPA must disapprove any implementation plan that does not include provisions for the PDS.
Under the guidelines of the PDS, the areas that meet the standards related to a specific pollutant areas are called successful. Areas not meeting these standards are not achieved areas. An area can be, for example, achieved for carbon monoxide while not achieved for sulfur dioxide. The states are responsible for establishing the boundaries of each geographic area considered in the program. Generally, these limits are the same as the county in the state.
The amendments to the Clean Air Act (Elal) 1990
In November 1990, the United States Congress again amended the Clean Air Act. The adoption of the 1990 amendments marked a general change in the federal method of controlling air pollution. The new law emphasized the emission control hazardous air pollutants and introduced áciday rain control of ozone depletion in the atmosphere. The effects of the 1990 amendments are discussed later along with other new initiatives of air pollution.

The Clean Air Act 1970 was amended in 1975, 1977 and 1990. Hazardous Air Pollutants (CPA)
The 1990 amendments changed the focus of the EPA to regulate the CPA at the federal level. Previously, national standards for pollutant emissions List hazardous air (NNECPA) were based primarily on health considerations.
A total of 189 of CPA are the target for control by creat-ing installation of maximum available control technology (TDMC). The Agency had difficulty in establishing these rules because of uncertainty in assessing health risks. Now the amendments require the EPA to set standards based exclusively available control technology. Control focuses on a total of 189 CPA by installing available technology for maximum control.
Acid rain
Acid rain refers to precipitation as rain, snow or fog that contains an excess of fatty due to air pollution. Acid rain can also refer to solid particles that are acidic. Acidity is measured by the pH on a logarithmic scale from 1.0 to 14.0. A pH of 1.0 indicates high acidity, while a pH of 14.0 indicates high alkalinity, a pH of 7.0 indicates a neutral solution. The precipitation that falls by an atmosphere "clean" is normally slightly acidic with a pH of approximately 5.6. However, acid rain can have pH values below 4.0. Acid rain is important because of the potentially harmful effects it can have on the water, aquatic life, wildlife and manmade materials.
The precipitation that falls by an atmosphere "clean" is normally slightly acidic with a pH of approximately 5.6. Pollution caused by man is one of the primary causes of acid rain. The oxides of sulfur and nitrogen from fossil fuel combustion are mixed with water in the atmosphere and causing acid rain. The 1990 amendments to the Clean Air Act require that we reduce emissions of sulfur oxide and nitrogen in the main emission sources. The amendments also require ongoing research into the effects of transport and deposition of acid rain.
ImageAcid rain results when SO x and NO x from fossil fuel combustion is mixed with moisture from the atmosphere. An innovative approach to control acid rain, brought by the 1990 amendments, is the use of incentives based on the market. The amendments promote this approach as a way to reduce costs involved in compliance of air pollution. For example, the law includes a licensing system for sulfur dioxide emissions. The industries that reduce emissions below the standard for sulfur dioxide can accumulate credits that can license or sell to other companies. This creates a market in which companies can trade or "build up" their claims, thereby establishing a market-based approach to encourage companies to reduce air pollution.
Ozone depletion in the stratosphere
The stratosphere (a layer of the upper atmosphere) contains ozone, which serves to protect the earth's surface from harmful ultraviolet radiation from the sun. However, in the lower portions of the atmosphere, ozone is harmful.
Researchers have discovered that synthetic compounds such as halocarbons and clorofluo-rocarbonos (CFCs) are destroying the protective ozone layer in the stratosphere. These compounds are used in many common products such as refrigerants, aerosol sprays and fire extinguishers. The Montreal Protocol promoted international efforts have reduced the ozone-depleting substances.
ImageSynthetic compounds such as halocarbons and chlorofluorocarbons (CFCs) are destroying the protective ozone layer in the stratosphere. Other initiatives
Indoor Air Pollution
Although past efforts to control air pollution mainly focused on external (or air), is now placing more emphasis on indoor air. Many people spend most of their time indoors and are therefore more prone to indoor air pollutants than the outdoor.
Many people spend most of their time indoors and therefore is more prone to indoor pollutants than the outdoor. Are currently conducting research and regulatory programs on indoor substances such as radon , asbestos, secondhand smoke snuff hand, formaldehyde, pesticides and chlorinated compounds as liquids and air deodorizers. The emphasis on control of indoor air pollution will continue as scientific knowledge advances.
Negotiating regulations
The development of regulations remains the main method of controlling air pollution. Unfortunately, the drafting of regulations is costly and time consuming. One approach to minimize the time and cost of a regulation to establish a standard through a process of negotiation of the rules. In a negotiation, representatives of interested parties meet to discuss the various regulatory alternatives. These representatives from industry, environmental groups, state and local agencies, and EPA. The goal is to develop a regulation that is accepted by all parties concerned. This method of developing the regulation is viewed with great optimism.
Initiatives for Voluntary Control
Also promote voluntary initiatives to control air pollution. One of the hallmarks of the 1990 amendments in an incentive program known as Early Reduction Program (PRA). The PRA provides an incentive to industries to reduce emissions of toxic pollutants before they regulate. This program benefits both the environment and industries.
Pollution prevention
Work has begun to emphasize the use of measures to prevent air pollution. The aim of prevention is to reduce the generation of pollutants at source as much as possible and recycle their generation. Preventing pollution may be reducing the volume or toxicity of waste.
It is causing the pollution prevention through the promotion of a hierarchy of four steps for environmental protection:
Step 1: Reduction of pollution from the source by using techniques such as better maintenance, changes in raw material use or installation of a new technology. Step 2: Recycle or reuse waste wherever possible. Step 3 Treatment and control. Step 4: Disposition of desechos.Las adequate pollution prevention measures that can reduce air pollution include:
· Replace or change the fuel or raw materials used in the production process.
· Change the process.
· Change the computer.
Improve operating practices and maintenance.
· Include a process and retrieve any air emission.
An example of a technique for pollution prevention would be to change the type of coal used as fuel in a power plant. The lower the sulfur content in coal, the lower the sulfur dioxide emission. Another example is the implementation of a program to detect and repair leaks at a chemical plant. The leaky valves and fittings produce high levels of air pollution. The monitoring of these sources of pollution will be beneficial to the chemical plant and the environment.
It is constantly seeking new approaches to the control of air pollution. Preventing pollution through market-based incentives, negotiation of regulations and voluntary programs are among the new initiatives to control air pollution. There is also greater awareness of the need to adopt an approach that encompasses the various environmental media to address the general problem of pollution. In other words, you can not get control of air pollution if they violate the regulations of solid waste and water pollution. As scientific knowledge advances, more problems will be identified environmental decontamination. This will lead to continuous changes in technical and policy approaches to control air pollution.
There is greater awareness of the need to adopt an approach that encompasses the various environmental media to combat the general problem of pollution. Can not get control of air pollution if they violate the regulations of solid waste and water pollution.
Mexico City: clean air plans and institutional

Mexico City and its metropolitan area is home to nearly 18 million people in a urban area that extends over 1,500 km2 dispersed. The metropolitan area of Mexico is located in a closed basin by mountains that limit entry of winds that disperse pollution. Its latitude and altitude, 2,240 meters above sea level, they receive stronger solar radiation that transforms nitrogen oxides and hydrocarbons emitted at high levels of ozone. Its height also affects the training almost daily temperature inversions, which prevent upward dispersion of pollutants and concentrated near the urban land.
Efforts to clean up the atmosphere of this metropolis, are very recent. Until 1986, it operated a small network of air monitoring manual measuring mainly sulfur dioxide, lead and particulate matter. During that year when the first Automatic Atmospheric Monitoring Network (RAMA) consists of 25 measuring stations in real time, which recorded levels of ozone (O3), carbon monoxide (CO), nitrogen oxides (NOx), dioxide sulfur (SO2), lead (Pb), total suspended particles (PST) and, since 1995, particles smaller than 10 microns (PM-10) and ultraviolet radiation (UV-B). The current RAMA covers much of the metropolitan area with 32 automatic and 12 manual stations in operation
For 1987-88, the RAMA produced a series continue and reliable records of air quality. Their data showed that it violated the rules of all pollutants, most days, reaching levels of concentration up to two to three times above international standards. By government decision, this information was first to inform society on a daily basis through mass media to promote the creation of a social conscience that would underpin the implementation of the measures needed to prevent and control emissions.
History of the Metropolitan Environmental Commission
In parallel, in early 1989, the Federal Government together with local governments and Federal District of Mexico State (entities on which rests the metropolis) formed an interagency group to analyze the causes and sources of pollution and to design and implement measures for its prevention and control. In analyzing the causes and sources of pollution was found that the problem was multi-sectoral and that its solution required the participation of numerous government agencies and private sector, labor, research institutions and academic and social representatives. Thus the work of the interagency group joined:
The Ministry of Urban Development and Ecology (now Ministry of Environment, Natural Resources and Fisheries, SEMARNAP) for being the entity responsible for proposing environmental regulations and standards and monitor compliance by the industry.
The Ministry of Health responsible for establishing the standards that set maximum exposure limits of the human body to pollutants and protect social health.
The Ministry of Energy, responsible for establishing policies to be complied with state bodies responsible for the development of petroleum fuels and electric power generation.
The Ministry of Education, responsible for education programs.
The Ministry of Industry and Trade, responsible for regulating the manufacturing and services.
The Ministry of Finance responsible for proposing budgets that Congress will exercise gubernamentales.La institutions Ministry of Communications and Transport, responsible for monitoring compliance with environmental regulations for transport by passing on federal roads between cities the country.
The Federal District, which sits half the population of the metropolis and entity responsible for controlling pollution from vehicles and utilities.
The Government of Mexico, where sits the other half of the metropolis and has the same responsibilities as the Federal District government.
Petroleos Mexicanos, the state company responsible for producing the oil products demand in the country.
The Federal Electricity Commission and the Society of Light and Power Center, responsible for the supply of electric power and operators of the two power plants operating within the air basin where the mother is located and which are the main consumers of fuel area.
The Mexican Institute of Petroleum, scientific research center of high oil, industrial and vehicular.
The comprehensive sanitation program atmospheric
After a year and a half of studies, drawing up an inventory of emissions and developing programs and projects for the control of pollutant emission sources, the interagency group produced the first comprehensive program to combat air pollution (PICCA ). The program is directed by five strategic lines of action:
1.To improve the environmental quality of fuels and promote the use of cleaner.
2.Modernizar vehicle fleet with cleaner technologies, expand and coordinate public transport and control emissions from all vehicles in environmentally circulación.Modernizar industry and ensure compliance with environmental regulations.
3.Proteger and restore the natural resources of the basin where the mother sits.
4.Develops scientific research on the phenomenon and its management alternatives, environmentally educate the public and promote citizen participation.
The strategic lines of action included 109 projects and actions that required an investment of public and private sector of approximately 4.2 trillion dollars, with the aim of lowering the 37.5% of emissions. For the preparation of diagnostics and prevention and control measures, the participating institutions were organized through the scheme by Project Groups. The World Bank contributed significantly to organize a panel of international experts who advised the Project Groups, as well as free technical assistance from more advanced environmental agencies in the world. Subsequently, the World Bank contributed to the implementation of measures providing direct funding and acting as a leader in the realization of additional lines of credit from other international financial institutions. Among the most important measures that began to implement since 1990 are:
The phasing out of leaded gasoline and reducing sulfur content, benzene (for toxicity) of olefins, aromatics and vapor pressure (to reduce its reactivity and contribution to ozone formation).
The increase in cetane number and the decrease of sulfur and aromatics in diesel.
Eliminating the supply of fuel oil (heavy fuel oil for industrial use with high sulfur content) and its replacement with natural gas or fuel (low sulfur) Transportation.
The requirement for all new vehicles incorporate gasoline catalytic converter and emission control systems that require additional in the United States of America.
The mandatory emissions testing twice a year for all vehicles in circulation.
The resumption of work to extend the Collective Transport System (Metro) today covers 178 km of roads spread over 10 routes.
The introduction of 4 100 new buses to expand the supply of public transport in the city, linking them with the services provided by Metro.
Setting an age limit for taxis and minibuses and its gradual replacement by units that incorporate a catalytic converter.
Establishment of the "Do not Drive Today" that restricts the movement of vehicles without catalytic converter, a working day a week.
The conversion of fleets of cargo transportation of the leading companies in the city, the use of liquefied petroleum gas, including the incorporation of closed loop catalytic converters.
Industry and Services
Establishing emission limits for all industrial pollutants and obligation to submit a verification of their emissions once a year.
Obligation to submit environmental impact statement for any new expansion, industrial establishment or modification.
Installation of evaporative emissions recovery throughout the entire process of storage and marketing of gasoline.
Ban the consumption of heavy fuel with high sulfur content. Substitution of diesel, fuel oil or diesel to natural gas, most important industries of the city (glass, chemical and food, among others).
Restoration of natural resources
Massive reforestation of parks, gardens and medians in urban and rural areas surrounding the city.
Protection of forest areas surrounding the metropolis informal settlements and preventing illegal logging
Scientific Research
Developing models for predicting the air quality to predict weather contingency measures and assess the impact of pollution control proposals.
Construction of an experimental station for distribution of gasoline, to conduct impact analysis of implementing systems vapor recovery devices in the process of distribution of gasoline.
Establishment of a laboratory to evaluate and certify motoquímia control devices for vehicle emissions, vehicle conversion equipment for use liquefied petroleum gas and natural gas and to study the potential for ozone formation in exhaust gases and different formulations of gasoline.
Environmental education and citizen participation
Inclusion of environmental issues in the compulsory school textbooks.
Production of video material, a book and pamphlets on the causes and means of control of air pollution, emphasizing the actions that each citizen can make.
Ecological neighborhood committees created to promote citizen participation in local environmental work.
The institutionalization of the Metropolitan Environmental Commission
The interagency group became, after 1992, the Metropolitan Commission for the Prevention and Control of Pollution in the Valley of Mexico, now known as the Metropolitan Environmental Commission (CAM). It was originally thought to create a centralized metropolitan environmental authority solely and directly. However, this authority would have had to absorb a significant number of legal powers, budgets, human and technical resources from other units. This would have required significant legal changes at the level of the Constitution of the country and profound organizational transformation over all participating institutions.So it chose the figure of a committee, each institution participates and contributes according to their legal powers to discharge its responsibilities and implement their own resources. The representatives of each institution in the Project Groups established to prepare the diagnosis, action measures and monitor their implementation, became coordinator of the contributions corresponding to each department within their institutions. Additionally, the Project Groups joined those public and private institutions whose participation was required for comprehensive and efficient implementation of the measures.
A substantial advance was the creation of the Advisory Board of the committee. This Council joined representatives of the private sector and labor, non-governmental organizations, local and federal Representatives and Senators, as well as leading scientists and academic institutions. The Council's mission is to propose actions, analyze the government's proposals, make recommendations and promote consultation and citizen participation.
PROAIRE: The second comprehensive plan of reorganization air.
In 1995, based on scientific information that had been generating and building on the achievements of its predecessor (IPCC), the preparation of the Program to Improve Air Quality in the Valley of Mexico 1995-2000 (PROAIRE). This program was basically the strategic lines of the former by strengthening and expanding prevention and control measures implemented to improve the quality of fuels, reducing emissions from transport and industry, and protect natural resources of the basin. PROAIRE were grouped in 94 actions that would require an estimated investment of 13.4 billion. Your objectives are the year 2000 almost 50% decrease in pollutants emitted to the atmosphere and reduce the environmental contingency days (up to 2.5 times the ozone standard). It was felt that this program would help reduce by 300 thousand cases a year the emergence of acute respiratory diseases.
But it also added a new element to perform actions on the relationship between urban development and air quality. The PROAIRE specified that "... urban environmental degradation due to overexploitation or environmental resource burden of the city" (resources and its air basin, where industrial users, transportation, services and even the unloaded their homes at no cost and emissions usually without penalty). Indicated that these resources needed to be handled without violating their critical thresholds, and establish and internalize the costs of use. He pointed out that accountability for private and public of these costs, environmental information must nurture a process that would advance knowledge and understanding to change behavior harmful to the environment.
Consequently PROAIRE proposed the incorporation of measures:
· Ecological land to protect natural resources,
· Actions to densify the urban area and thus accommodate population growth without encroaching on the green areas surrounding the city,
· Conditions creating new housing to urban impact statements and environmental
· Streamlining the construction of new intra-urban roads and promote private investment in public transport
· Integrate metropolitan policies to link transportation system development to urban development plans, with an environmental vision.
· Construction of transfer stations private to public transport,
· Application of economic instruments to promote environmental policy (parking meters, parking rates differentials, mandatory auto insurance, higher public transport subsidies, etc.)..
During nine years of progressive incorporation of prevention and control, rates of concentration of pollutants have been declining. Three of the six criteria pollutants are now permanently in the air quality standards that protect health: CO, SO2 and Pb. NOx and occasionally slightly beyond the norm. Peak levels of ozone concentration have been reduced to levels that exceeded three times the norm, less than two and a half. Yet even these concentrations are very high and the rule violations recorded approximately 320 days a year. Finally particles smaller than 10 microns (PM-10) which penetrate to the inside of the lungs causing severe damage to health, keep reaching maximum concentration levels equivalent to twice the norm, although the days of violation show declining trends.
The third comprehensive program of air quality
The Metropolitan Environmental Commission (CAM) has begun work to prepare a program on air quality for the metropolitan area of Mexico City. For its development, has begun an evaluation / audit of the achievements and failures PROAIRE. It will identify the factors that allowed or prevented the achievement of results and barriers to be overcome to achieve the objectives that remained outstanding. Additionally, supported by the World Bank, the MAC conducted in June 1999 an International Workshop on Clean Air, which included the participation of leading international experts and national institutions CAM members, experiences of other cities around the globe, NGOs, researchers related scientific and ecology. His contributions and participations included answers to key questions: What has been achieved in our metropolitan area? What are the challenges ahead? What are the experiences of other cities and environmental agencies in the world? What remains to be done in Mexico City? With all this wealth, the MAC will be launching a participatory and socially analytical process for preparing the third air quality program that will guide actions to continue the atmospheric reorganization over the next ten years.

Air pollutants
The atmosphere is composed of several layers of air. The most relevant for studying the control of air pollution are called troposphere and stratosphere. The troposphere is the thin layer of relatively dense air closer to the surface of the earth. The troposphere contains the air that all living things need to breathe. The stratosphere is the protective layer of air that helps absorb and disperse solar energy.
Composition is unknown unpolluted air. Humans have lived on Earth for thousands of years and its many activities have influenced the composition of the air before it was possible to measure its components. The air is a complex mixture of many substances. The main constituents of air are nitrogen, oxygen and water vapor. Approximately 78 percent of air is 21 percent nitrogen and oxygen. The remaining one percent contains small amounts of substances such as carbon dioxide, methane, hydrogen, argon and helium.
In theory, the air has always been some degree of contamination. Natural phenomena such as volcano eruptions, windstorms, decomposition of plants and animals and even aerosols emitted by the oceans 'contaminate' the air. However, when talking about air pollution, contaminants are those generated by human activity (anthropogenic). It can be considered as a contaminant to the substance that produces a detrimental effect on the environment. These effects can alter both the health and welfare of people.
There are hundreds of air pollutants that are in the form of particles and gases. Particulate matter consists of small liquid or solid particles of dust, smoke, fog, and fly ash. Gases include substances such as carbon monoxide, sulfur dioxide and volatile organic compounds. You can also classify as primary or secondary pollutants. A primary pollutant is one that is emitted into the atmosphere directly from the source and has the same chemical form, such as ash from the burning of solid waste. A secondary pollutant is one that undergoes a chemical change when it reaches the atmosphere. One example is the ozone that comes from organic vapors and nitrogen oxides emitted by a gas station or car exhaust. Organic vapors react with nitrogen oxides in the presence of sunlight and produce ozone, a primary component of photochemical smog.
Air pollutants are also classified as criteria pollutants and contaminants do not approach. The criteria pollutants have been identified as common and detrimental to the health and welfare of human beings. They were called criteria pollutants because they were objects of evaluation studies published in papers air quality criteria. At the international level criteria pollutants are:
· Carbon monoxide (CO)
· Sulfur oxides (SOx)
· Nitrogen oxides (NOx)
· Ozone (O3)
· Lead (Pb)
· Particulate matter
The amendments to the Clean Air Act 1990 of the United States established a new category of pollutants called hazardous air pollutants (CPA). The Act listed 189 compounds as hazardous air pollutants. Criteria pollutants and hazardous air pollutants listed below.
The criteria pollutants
As indicated in the previous section, the criteria pollutants are carbon monoxide, sulfur oxides, nitrogen oxides, ozone, particulate matter and lead. In the last ten years, several countries in defining the total suspended particles specified the particles 10 microns or less in diameter and particles of 2.5 micrometers or less in aerodynamic diameter. These particles are commonly referred to as PM10 and PM2, 5 respectively. The rationale for this specification is that smaller particles are more dangerous to the health of humans because they are able to reach the bottom of the lungs.
Initially, the list of criteria pollutants are included hydrocarbons. Hydrocarbons, also called volatile organic compounds (VOC) are precursors to ozone formation. Although there are usually regulations that control VOC, no specific monitoring for VOCs in the air. The proper control of VOCs is reflected in the reduction of ozone concentration in the air.
For each criteria pollutant are established guidelines and standards. The guidelines are recommendations for levels of exposure to air pollutants in order to reduce the risks or protect from harmful effects. The standards set the maximum allowable concentrations of air pollutants during a defined period. Limit values are designed with a margin of protection against risks. The purpose of the rules is to protect human health (primary standards) and protecting the welfare of humans and ecosystems (secondary rules). WHO has issued guidelines on air quality and several Latin American countries have established their own rules. Table 4-1 shows the average time limits and sampling of national standards for air quality ozone, sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), total dust matter (TSP), PM10 and lead that have been established in several countries of America and the WHO guidelines.
ImageTable 4-1 National Standards for air quality in different countries of America and WHO guidelines
Below is each pollutant approach.
ImageCarbon monoxide (CO) ImageOzone (O3) ImageSulfur oxides (SOx) ImageParticulate matter ImageNitrogen oxides (NOx) ImageLead (Pb)
Progress in the control of criteria pollutants
Efforts to control criteria pollutants in developed countries have shown some positive results, although much remains to be done. Since 1970, levels of sulfur oxides, carbon monoxide and particulate matter in air are reduced, while lead has been eliminated almost completely. However, the nitrogen oxide emissions have increased slightly and the smog problem remains difficult to resolve. Although there have controlled many of the sources that produce smog, the large number of vehicles and additional sources has unbalanced the achievements under the reduction.
Hazardous Air Pollutants (CPA)
Hazardous pollutants are carcinogenic and non carcinogenic compounds that can cause serious and irreversible effects on health. As indicated above, the amendments to the Clean Air Act of 1990 U.S. 189 compounds listed as hazardous air pollutants (CPA), including carbon tetrachloride, chlorine, ethylene oxide, cadmium and manganese. Most CPA's are volatile organic compounds.
The rules for controlling the emission of these hazardous pollutants are based on health. In other words, establishing numerical limits that protect human health from any adverse effects.
However, the establishment of emission standards based on health is a difficult process due to uncertainty in the evaluation of health effects. As a result, America has set emission standards based on health alone for eight pollutants: asbestos, vinyl chloride, benzene, arsenic, beryllium, mercury, radon and radon radionuclides different.
The eight pollutants are:
· Asbestos
· Vinyl chloride
· Benzene
· Arsenic
· Beryllium
· Mercury
· Radon
· Radionuclides other than radon.
Asbestos is known to cause cancer in humans. Unfortunately, fire resistance favored its use in many materials such as insulation, paints, coating automotive brake and even clothing.
Vinyl chloride
Vinyl chloride is used in the production of plastics and polyvinyl chloride (PVC). Exposure to vinyl chloride can damage the liver and other organs.
Benzene is a carcinogenic compound used in degreasing agents, gasoline and solvents. It has promulgated several regulations to control the emission of benzene, including rules for the escape of benzene in equipment, for containers of benzene and transport operations and waste disposal of benzene, and plant by-product recovery coke.
Arsenic is also a carcinogen. It is used in the manufacture of glass and metal smelting. The emission standards were set to control the release of arsenic from glass manufacturing plants, smelters and facilities for the production of arsenic.
Beryllium can cause lung disease and also has adverse effects on the liver, spleen, kidneys and lymph glands. Beryllium sources include metal foundries, ceramic plants and incinerators that burn waste with beryllium.
Mercury can have adverse effects on the brain and kidneys. The sources of mercury include burning of fossil fuels, battery manufacturing plants and mercury mining processes that use mercury.
Radon is a naturally occurring radioactive element. Also found in building materials that contain substances that give off radon, such as gypsum. Radon is known to cause various forms of cancer and is a major pollutant of indoor air. So far, they have established rules to control the emission of radon in underground uranium mines, quarries and phosphogypsum tailings from mines and processes uranium.
Radionuclides are a category of radioactive materials other than radon. A radionuclide is any nuclide that emits radiation. Just as radon, these materials can cause cancer in humans.


The quality of everyday life depends on many modern facilities. People are free to drive cars and travel on airplanes for business and pleasure. They hope that their homes have electricity and hot water for bathing and cooking. They use a wide variety of products, clothes, medicines and furniture, made of synthetic materials. At times, rely on services that use chemical solvents, such as laundry and printing. However, the availability of these everyday conveniences will cost about environmental pollution. This lesson will address the various sources of air pollution, many of which are essential to maintain an industrialized society.
When discussing the sources of air pollution, commonly used four terms: mobile, stationary point and area. Mobile sources include various forms of transport such as cars, trucks and planes.The stationary sources are not mobile facilities such as power plants and industrial facilities. A point source refers to a source at a fixed point, such as a fireplace or storage tank that emits pollutants. A source area refers to a series of small sources that collectively may affect air quality in a region. An example would be a community using wood for heating.
Mobile sources of air pollution
Mobile sources of air pollution are well known and include cars, buses, locomotives, trucks and planes. These sources emit criteria pollutants and other hazardous pollutants.
The primary mobile source of air pollution is the automobile, because it produces large amounts of carbon monoxide, and smaller amounts of nitrogen oxides and volatile organic compounds (VOCs). Emissions from automobiles also contain lead and trace amounts of some hazardous pollutants. The requirements for automobile emission control have greatly reduced the amount of air pollutants.
The primary mobile source of air pollution is the automobile, because it produces large amounts of carbon monoxide, and smaller amounts of nitrogen oxides and volatile organic compounds (VOCs). Emissions from automobiles also contain lead and trace amounts of some hazardous pollutants. The requirements for automobile emission control have greatly reduced the amount of air pollutants. In addition, regulations that control the quality of fuel from cars have also contributed to greater efficiency and lower emissions. For example, the transition from leaded to unleaded petrol has dramatically reduced the amount of lead in ambient air. However, due to the increasing number of vehicles, cars remain the main mobile source of air pollution.
Trucks, buses and diesel locomotives are generally using a different fuel for most cars. The burning fuel for diesel engines produce more nitrogen oxides. For example, in California an estimated 850,000 trucks and diesel buses produce as much nitrogen oxides than 8 million cars a year.
The jet fuel burned also different from most cars. The primary pollutant produced by burning jet fuel is nitrogen oxide. The jets also produce amounts of carbon monoxide and hydrocarbons.
A modern transport system is essential for the country's economic growth. Air pollution generated by cars and other forms of transportation is an award accepted by most people. Fortunately, advances in the technology of pollution control, alternative fuels and changes in lifestyle, such as sharing and mass transport can minimize the harmful effects of these needs in an industrialized society.
Stationary sources
There are hundreds of thousands of stationary sources of air pollution, including power plants, chemical plants, oil refineries, factories, print shops, laundries and residential use wood fireplaces. Stationary sources produce a wide variety of air pollutants. According to the industry or process specific stationary sources can emit one or more criteria pollutants besides many hazardous pollutants.
Stationary source pollutants come mainly from two activities: combustion of coal and oil in power generation plants and the loss of contaminants in industrial processes. Industrial processes include refineries, chemical plants and foundries. The chemical industries are responsible for many harmful pollutants and large amounts of volatile organic compounds.
There are many specific points of issue within a stationary source that pollutes the air. For example, in the chemical industry, air pollutants can be emitted from vents, storage tanks, wastewater management and treatment areas, loading and unloading facilities, and equipment leaks. A vent is basically a passage through which the substances (mainly in gaseous form) is "vented" to the atmosphere. Typical ventilation ducts in a chemical plant is the distillation columns and ducts of oxidation.
Generally, the storage tanks are round container that stores liquid raw material and finished products. While most tanks are covered, contaminants can be delivered by drip and expansion and cooling of liquids caused by temperature changes in outdoor air. As the liquid expands and contracts, the tank "breathes" and force vapors out through openings in the tank. In addition, pollutants can be emitted during filling and emptying routine storage tanks.
The sewage within a stationary source can also cause air pollution. If wastewater contains substances "volatile", they will be released from the wastewater comes into contact with air. Volatile means that the chemicals can evaporate or move from one liquid gas. There are many places within a stationary source where the wastewater comes into contact with the outside air.
Emissions also come from leaks in the equipment and loading and unloading of chemicals in trucks, trains and boats. Leaks in the kit are a primary source of emissions, in particular in chemical industries and refineries. The term "equipment leak" refers to a large source of emission points, including valves, joints, pumps and valves. There may be thousands of these components in a particular installation.
The EPA classifies the sources of hazardous pollutants into two groups: major sources and area sources. The major sources are stationary sources that emit 10 tons per year or more in a single hazardous air pollutant or 25 tons per year or more of any combination of hazardous pollutants. The area source is any source of dangerous pollutants that is not a primary source. This definition excludes automobiles.

Definitions · Main source: stationary source that emits 10 tons per year or more of a hazardous air pollutant or 25 tons per year or more of any combination of hazardous air pollutants. · Area Source: Any source of hazardous air pollutants not a primary source. This definition excludes automobiles. As mentioned above, there are hundreds of thousands of air pollution sources. Many of these sources generate useful consumer products, create millions of jobs and provide services and amenities. While not practical to remove all sources of air pollution, ways to minimize them are discussed in the following lessons. The control and abatement can be achieved through the installation of devices, changes in production processes and implementation techniques of pollution prevention.


Principles of transport and dispersion
The transport and dispersion of air pollutants are influenced by complex environmental factors. Global and regional variations of climate and local topographic conditions affecting transport and dispersion of pollutants. This lesson discusses the basic factors that influence the movement of pollutants in the ambient air.
In a global climate changes influence the movement of pollutants. For example, the prevailing winds in Central America and northern South America is from east to west in North America and southern South America is from west to east. On a more local level, major transport and dispersion factors are wind and stability.
The prevailing direction of winds in Central and northern South America is from east to west in North America and southern South America is from west to east. The dispersion of pollutants from a source depends on the amount of turbulence in the atmosphere close. Turbulence can be created by the horizontal and vertical movement of the atmosphere. The horizontal movement is what is commonly called wind. Wind speed can greatly affect the concentration of pollutants in an area. The higher the wind speed, the lower the concentration of pollutants. The wind quickly dilutes and disperses pollutants in the surrounding area.
The higher the wind speed, the lower the concentration of pollutants. The wind is caused by differences in atmospheric pressure. Pressure is the weight of the atmosphere at a given point. The height and temperature of an air column determines the atmospheric weight. Because cold air is heavier than hot, high pressure mass of cold air is made heavy. By contrast, a mass of low air pressure is formed by warmer air and light. The pressure differences cause air to move from areas of high pressure to low pressure, which results in the wind.
The vertical movement of the atmosphere also affects the transport and dispersion of air pollutants. When meteorologists talk about the "atmospheric stability" refers to the vertical movement. Unstable atmospheric conditions produce vertical mixing. Generally, during the day the air near the surface of the earth is warmer and lighter than air in the upper atmosphere due to absorption of solar energy. The hot air and light from the surface rises and mixes with cold air and heavy in the upper atmosphere that tends to fall. This constant movement of air creates unstable conditions and disperse contaminated air.
Generally, when the warmer air is above the cold air stable atmospheric conditions occur, thereby inhibits vertical mixing. This condition is called thermal inversion. When there is a slight vertical mixing or no mixing, the contaminants remain in the lower and tend to occur at higher concentrations.
The stable atmospheric conditions occur when warmer air is above the fresh air, thereby inhibiting vertical mixing. This condition is called thermal inversion.Other basic meteorological factors affecting pollutant concentrations in ambient air are:
· Solar radiation
· Precipitation
• Moisture.
Solar radiation contributes to the formation of ozone and secondary pollutants in the air. The humidity and precipitation may also promote the emergence of hazardous secondary pollutants, such as the substances responsible for acid rain. Precipitation can have a beneficial effect because it washes the air pollutant particles and help minimize the particles from activities such as construction and some industrial processes.
Because the factors that determine the transport and dispersion of pollutants, air pollution produced in one region can have adverse effects on lakes and forests in another region. The large cities surrounded by complex topography, such as valleys or mountain ranges, often experience high levels of air pollutants. Although little can be done to control natural forces that create these problems, there are techniques that help to disperse pollutants. The most common way to disperse air pollutants is through a chimney.
The most common way to disperse air pollutants is through a chimney. The fireplace is often used as a symbol of air pollution. It is a structure commonly seen in most industries. A fireplace disperses pollutants before they reach populations. Generally designed taking into account the surrounding community. The higher the chimney, the greater the likelihood that pollutants are dispersed and diluted before affecting neighboring populations.
The higher the chimney, the greater the likelihood that pollutants are dispersed and diluted before affecting neighboring populations. A visible emanation of a chimney is called a pen. The boom height is determined by the speed and pressure of the gases leaving the chimney. Often, heat energy is added to gas to increase the height of the boom. Natural forces cause the pen has vertical speed, like smoke from residential chimneys.
The following figure shows the effects of the height of the chimney and the immediate surroundings on the shape of the pen. The shorter the chimney, the greater the likelihood that the pen is affected by the "cavity" formed by the building next to the fireplace. As you increase the height of the chimney, the pen moves away from the building. The shape and direction of the pen also depend on the vertical and horizontal forces of the atmosphere. As mentioned above, the pen is affected by atmospheric conditions. The unstable conditions in the atmosphere will produce a pen "wavy", while the stable will make the pen is "upright.
Image Distribution of pollutants injected into the cavity and outside pollutants emitted by smokestacks can be transported over long distances. In general, the pollutant concentration decreases as they move away from the discharge point and are dispersed by wind and other natural forces. Climatic variations influence the general direction and dispersion of pollutants. For example, in the United States pollutants released in the Midwest affecting people and the natural habitat of the eastern region. The weather patterns also cause pollution problems like acid rain, which are issues of regional and international concern.
The pollutants emitted by smokestacks can be transported over long distances. In general, the pollutant concentration decreases as they move away from the discharge point and are dispersed by wind and other natural forces. The dispersion and transport of pollutants may be affected by climatic and geographical factors. An example is the thermal inversion. As mentioned above, the inversion is an atmospheric condition caused by a disruption of the normal profile of the temperature of the atmosphere. The inversion can keep the rise and dispersion of pollutants in the lower layers of the atmosphere and cause a localized problem of air pollution. The episodes that took place in London, England, and Donora, Pennsylvania, were the result of inversions.
ImageA temperature inversion is an atmospheric condition caused by a disruption of the normal profile of the temperature of the atmosphere. The inversion can keep the rise and dispersion of pollutants in the lower layers of the atmosphere and cause a localized problem of air pollution. The proximity of a large metropolitan area to a mountain may also have a negative effect on transport and dispersion of pollutants. Los Angeles, Denver and Mexico City are located in basins surrounded by mountains. These cities are experiencing high levels of air pollution influenced by the topography of the surrounding area. While the causes of their pollution problems are complex, these cases show how natural factors conducive to higher concentrations of pollutants.
While little can be done to minimize the effects of natural forces on the transport and dispersion of pollutants, the best available strategy is to prevent the production of air pollutants at the source.
Dispersion models
The dispersion models are a method to calculate the concentration of pollutants at ground level and at various distances from the source. In developing mathematical models used representations of the factors affecting the dispersion of pollutants. The computers, using models facilitate the representation of the complex systems that determine the transport and dispersion of air pollutants.
The dispersion models are a method to calculate the concentration of pollutants at ground level and at various distances from the source. When you make a model of the transport and dispersion of air pollutants collected information specific to a release point. This information includes the location of the emission point (longitude and latitude), the amount and type of pollutants emitted, the conditions of the gas fireplace, chimney height and meteorological factors such as wind speed, temperature profile and atmospheric pressure. Scientists use these data as input into the computer model and predict how contaminants are dispersed in the atmosphere. The concentration levels can be calculated for various distances and direction of the fireplace.
Dispersion models have many applications in controlling air pollution because they are tools that help scientists to assess the dispersion of air pollution. The accuracy of the models is limited by the problems inherent in trying to simplify the complex and interrelated factors affecting transport and dispersion of air pollutants.
The dispersion models are tools to help scientists to assess the dispersion of air pollution.


Principles of air sampling and analysis
The components of a system for monitoring air pollution include the collection or sampling of ambient air pollutants and specific sources, analysis and measurement of the concentration of pollutants, and the report and use the information collected. Sampling and analysis of ambient air and emission of point sources are important for several reasons.
We can measure the ambient air and source emission. Data on concentrations of air pollutants are used to determine compliance with air quality standards. They are also used to diagnose the conditions of an area before building a new source of pollution, to develop models of dispersion of pollutants, to conduct scientific studies to assess human exposure to pollutants and environmental damage.
Air Monitoring: Sample Collection Sample Analysis Reporting and use of information collected emissions data from point sources are used to determine compliance with air pollution regulations, effective control of air pollution, efficiency production and to support scientific research.
The institutions responsible for monitoring air quality generally designated reference methods for sampling and analysis of pollutants and emission sources. The methods specify precise procedures to be followed for any activity relating to compliance monitoring regulation.
The institutions responsible for monitoring air quality generally designated reference methods for sampling and analysis of pollutants and emission sources. These procedures guide the sampling, analysis, instrument calibration and calculation of emissions. The choice of specific method of analysis depends on a number of factors, the most important chemical characteristics of the pollutant and its physical state-solid, liquid or gaseous. The reference methods are designed to determine the concentration of a contaminant in a sample. The concentration is expressed in terms of mass per unit volume, usually in micrograms per cubic meter.
There are some basic principles and terminology associated with the sampling and analysis of the contaminant. The sample collection can be done by manual or automatic. The analysis and measurement of pollutants can be done through various means such as chemical and physical characteristics of the contaminant. One method for measuring particulate matter is to use gravimetric principles. Gravimetry refers to the measurement of weight. The particles are trapped or collected on filters and weighed. The weight of the filter with contaminant collecting less the weight of a clean filter gives the amount of particulate matter in a given volume of air.
The measurement of particulate matter using gravimetric principles. Gravimetry refers to the measurement of weight.
Weight of the filter with the collected pollutant clean filter + Weight = quantity of particulate material in a given volume of air atomic absorption is used to measure lead. Following the lead particles collected by gravimetric methods, lead is extracted from the sample by acid. In the process of atomic absorption, lead absorbs small amounts of radiation. The radiation emitted by the sample allows to know the amount of lead atoms in the sample.
The atomic absorption is used to measure lead. Gaseous pollutants can be measured with different methods. The most common techniques include spectrophotometry, gas-phase chemiluminescence and flame ionization.
Spectrophotometry is based on colorimetric principles and commonly used to measure the concentration of sulfur dioxide. In this process, dyes and chemicals are combined with a solution containing sulfur dioxide. The color of the solution leads to different amounts of light absorbed. The amount of light absorbed, measured with a spectrophotometer, this indicates the amount of sulfur dioxide.
Spectrophotometry is based on colorimetric principles and commonly used to measure the concentration of sulfur dioxide. The gas-phase chemiluminescence is a method to measure ozone. In this method, by chemical reaction with ethylene, ozone emits light and that light is measured with a photomultiplier tube. The amount of light indicates the amount of ozone present.
ImageThe gas-phase chemiluminescence is a method to measure ozone. The burning flame ionization air sample with a small flame gaseous hydrogen. The number of ions or electrons formed is proportional to the number of carbon atoms found in the sample and account electronically. This technique can be used to measure volatile organic compounds (hydrocarbons). Because this method also detects carbon in methane, a relatively harmless gas that occurs naturally in the atmosphere, corrections must be made to justify their presence.
The table presents the various methods used for measuring and analyzing air pollutants and basic principles for the measurement.
Examples of methods of measurement and analysis of air pollutants
MétodoPrincipioContaminante Ionization of llamaResponde in proportion to the number of carbon atoms in the sample gasCOVAbsorción infrarrojaLa sample absorbs radiation in the infrared spectrum, measured the difference in absorption. Using other regions of the spectrum, for example, UVMonóxido of carbonoAbsorción atómicaLa sample absorbs the radiation, the radiation depends on the excited sample atoms can presentes.PlomoEspectroscopía defluorescenciaLa reissue excitadaOzono excess energy, NO2Recolección of partículasGravimetría; the mass of particulate matter is determined by weight PM10EspectrofotometríaSe form colored solutions by mixing the reagents with the final result contaminantesSO2El Sampling and analysis are the quantitative data. The validity of the data depends on the accuracy and precision of the methods used to generate data. To ensure the validity, used various measures of quality control for each of the reference methods. The main measure of quality control is the calibration. Calibrationverifies the accuracy of a measurement to establish the relationship between the result of a measurement process and a standard of known concentration. Each of the reference methods is precise calibration procedures to be followed to ensure accurate results.
The calibration checks the accuracy of a measurement to establish the relationship between the result of a measurement process and a known input. We have also developed extensive programs for quality assurance to ensure the validity of the data. An essential component of the program of quality assurance audits are data. In an audit, one or more laboratories analyze a known standard sample of a pollutant. If laboratories obtain the desired result can be sure that their methods and procedures are accurate.
In an audit, one or more laboratories analyze a known standard sample of a pollutant. Monitoring the concentration of pollutants in the air
In the Valley of Mexico, Santiago, Sao Paulo and other cities of Latin America have established monitoring systems to measure the concentration of criteria pollutants and progress in meeting the goals established by law.
For example, in São Paulo, the Society of Environmental Sanitation Technology (CETESB) is in charge of the administration and operation of air monitoring stations located in the State of São Paulo, Brazil. Since 1981, the CETESB operates more than 25 automatic stations and 15 manual stations.
In general, all monitoring stations in a network to standardize the criteria for the identification, implementation and quality assurance monitoring. There are specific procedures to be followed in conducting the sampling criterion for each pollutant. These detailed procedures are the reference methods, which are reviewed and updated according to the advance of technology.
All monitoring stations in a network to standardize the criteria for the identification, implementation and quality assurance monitoring. The reference methods can be manual or automated. The manuals are specific techniques to follow when collecting and analyzing the sample of an air pollutant. An automated reference method generally refers to an instrument approved that meets the technical requirements for accurate data collection and analysis of a pollutant. Automated methods are used primarily for collecting and analyzing air permanently.

The reference methods can be manual or automated. The following figure presents a high volume sampler is used as a manual method to measure total suspended particles (TSP) and airborne lead. In this process gravimetric sampler pump in high-volume air creates a vacuum that carries air to a house deck. Air passes through a filter that traps particulate matter. To determine the amount of particulate material in an air sample, the filter is weighed before and after sampling. The weight difference is the amount of particulate matter trapped in the filter. Lead concentration is determined by additional extraction techniques and atomic absorption.

ImageTo determine the amount of particulate material in an air sample, the filter is weighed before and after sampling.It is developing more sophisticated equipment to measure the concentration of particulate material in the environment because as criteria pollutants under consideration to the PTS with less than 10 microns in aerodynamic diameter (PM10) and particulate matter less than 2.5 micrometers in diameter ( PM2, 5). The air sampler of high volume contains devices that separate the large particles of small and placed in the sampling device so that air passes through the device before passing through the filter. This will remove particles that exceed the specified diameter.
There are numerous automated methods for sampling and measurement of environmental contaminants. The process of gas-phase chemiluminescence, discussed above, is used to measure ozone. In a chamber, the air sample is combined with ethylene and the chemical reaction between ozone and ethylene creates pulses of light that are detected and counted by a photomultiplier tube. The ozone concentration is determined by comparing the number of pulses of the sample with the number of pulses of a sample with known concentration of ozone.
The technology to measure air pollutants is still evolving. The latest air monitoring include the use of infrared and ultraviolet rays to detect and measure criteria pollutants and toxic. Infrared spectroscopy Fourier transform (EITF) can be measured directly over 120 gaseous pollutants in the air as carbon monoxide, sulfur dioxide and ozone. The EITF also can measure toxic pollutants such as toluene, benzene and methanol. The technology is based on each gas has its own "fingerprint" or absorption spectrum. EITF sensor monitors the entire infrared spectrum and read the fingerprints of different gases in the air. Specific applications are being developed for this technology.
The latest air monitoring include the use of infrared and ultraviolet rays to detect and measure criteria pollutants and toxic.
Infrared spectroscopy Fourier transform (EITF) can be measured directly over 120 gaseous pollutants in the air as carbon monoxide, sulfur dioxide and ozone. The environmental monitoring data are used for different purposes. They are used to monitor progress in meeting national goals for air quality and human exposure assessment. Also, to develop and evaluate the air dispersion models, execute plans and conduct scientific studies of air pollution.
Measurements of emissions of pollutants
The measurement of pollutants from point sources is generally made for specific purposes, for example, to assess compliance with emission standards, measure the effectiveness of control technologies and to carry out scientific research. A term used frequently in relation to the sample of a stationary source is "fire proof". This is because many of the measurements taken in industrial smokestacks. In fact, measurements can be taken elsewhere.
A common term used in reference to a sample of stationary source is "fire proof". To determine the emission of pollutants from a source uses four reference methods. These methods provide insights into the appropriate location of the sample, the speed or gas flow rate, composition of the gas flow and moisture content of the gas stream. These four methods are used along with other specific methods designed to measure the concentration of pollutants such as particulate matter and sulfur dioxide.
To determine the emission of pollutants from a source uses four reference methods. In the next figure appears sampling equipment specified by the method of reference 5 of the EPA for particulate measurement. Commonly referred to as the "method of train 5", this sampling configuration can be modified to measure various pollutants. The method consists of a train 5 sampling probe, a filter located in a heated box, a series of hammers and ancillary equipment like a pump, dry gas meter and pressure gauges to measure pressure changes. The probe collected the sample that passes through a filter where particulate matter is trapped. Then the gas passes through the hammers submerged in ice to remove moisture from the gas stream. The gas meter measures the flow rate while the pump and pressure gauges are used to maintain isokinetic conditions during the sampling period. The isokinetic defined as the ratio between the flow of gas from a fireplace with gas flow of a sample probe. It is important that these flows remain equal to gather a representative sample.
The isokinetic defined as the ratio between the flow of gas from a fireplace with gas flow of a sample probe. Image
Emission inventories
Data collected from the measurement of air pollutants and emission sources can be useful for professionals in air pollution. The development of emission inventories is a byproduct of managing such data.
Emission inventories are detailed listings of pollutants emitted by specific sources in a given area. Are valuable tools for planning and evaluation and help define the relationship between pollutant sources and the surrounding communities, contribute to the development of alternative strategies to control pollution and provide concise information on pollutant sources and emissions.
The development of an inventory is a tedious and detailed. The inventory data that are to be collected and analyzed carefully. It must follow strict guidelines for quality assurance to ensure the accuracy and validity of the inventory.


How limiting the emission of pollutants without the use of aggregate control?
Some techniques for controlling the emission of air pollutants do not require additional equipment, while others require control "added." The added control is one that is added to the processes that generate pollution in order to destroy or capture contaminants. The technical means for controlling the emission of pollutants in a given source depends on many factors, the most important is whether the contaminant is a gas or a particle.
As seen above, there are pollutants in gaseous, liquid and solid. The gaseous pollutants include sulfur oxides, nitrogen oxides, carbon monoxide and volatile organic compounds (VOCs). Many harmful contaminants are gases. The contaminants in liquid and solid, called particulate matter, including cement dust, smoke, fly ash and metal fumes.
Techniques to limit emissions of air pollutants without the use of added control are:
· Change Process
Change fuel ·
· Good operating practices
· Lock plant
These control methods are applied to both gases and particles.
For example, a change in the conversion process can be a source of fossil fuel energy used into one that uses solar or hydropower. Solar energy generators and pollute the air less hydroelectric generators that burn fossil fuels. An example of fuel switching is the use of coal with low sulfur to replace coal with high sulfur content. This would reduce the amount of sulfur dioxide emissions. Another example of changing the fuel would replace coal with natural gas, which is less polluting.
Good operating practices include common sense measures, such as care and proper maintenance of equipment. An example of this technique is the inspection and regular maintenance to ensure no leakage of volatile organic compounds in a chemical plant. Leaks from equipment may be an important source of volatile organic compound emissions. A regular inspection program with simple devices for leak detection, along with rapid repair and maintenance system, can greatly reduce this source. Besides reducing emissions, good practices of care and also reduce maintenance costs by avoiding the loss of expensive materials.
Regular inspection of equipment for leaks can help to reduce pollutant emission sources. Finally, the closure of plants is an effective technique to reduce pollution. This may be necessary in extreme cases, for example, during an episode of air pollution. To reduce air pollution is also effective to replace old plants by modern facilities.
Devices and techniques for gaseous pollutants
The most common method of control of gaseous pollutants is the addition of control devices added to destroy or retrieve a pollutant. Control techniques are added combustion, adsorption, absorption and condensation. Combustion devices include equipment such as thermal and catalytic incinerators, burners, industrial boilers and heaters. Combustion is the rapid oxidation of a substance derived from a combination of oxygen with a combustible material l in the presence of heat. When complete combustion, the gas flow is converted into carbon dioxide and water vapor. Incomplete combustion releases some air pollutants. The smoke is an indicator of incomplete combustion. A common example of incomplete combustion is the burning of wood in the fireplace of a house.
The smoke is an indicator of incomplete combustion (eg burning wood in a fireplace) Adsorption, absorption and condensation are recovery techniques. Some devices that use these techniques are the carbon adsorber, the tower spray and surface condensers. These techniques apply simple physical principles to remove contaminants in a gas flow. These principles are discussed in more detail below, together with the description of some specific control devices.
Control devices and techniques of gaseous pollutants:
ImageThermal Incinerators ImageCatalytic Incineration ImageLlamas ImageIndustrial Boilers ImageCarbon adsorber ImageAbsorbers ImageCondensers ImageEquipment and work practices factors determining the choice of a technique to control emissions of gaseous pollutants are:
· The chemical properties of the contaminant.
• The value of the contaminant if recovered.
· Control costs.
• The impact of technology on pollution control of water or solid waste production.
Control techniques and devices for solid and liquid particles
Particulate matter includes small particles and liquid and solid is also described as smoke, dust, vapor or mist. As already mentioned, particles less than 10 and 2.5 micrometers in diameter are known as criteria pollutants. These small particles have a much greater effect on human health than larger particles. Control techniques for particulate matter focus on capturing the particles emitted from a pollution source.
Before choosing a particulate control device must consider many factors. Usually, the particles are collected and channeled through a canal or fireplace. The characteristics of the stream of particles affect the choice of control device. These characteristics include the size range of particles in the exhaust stream, the exhaust flow rate, temperature, moisture content and chemical properties of the flow of the exhaust stream as explosive capacity, acidity, alkalinity and flammability.
More control devices used to control particulate emissions are:
ImageElectrostatic precipitators ImageFilters ImageVenturi Scrubbers ImageSettling chambers ImageCyclones In many cases, using more than one of these devices in series to obtain the desired efficiency of removal. For example, you can use a settling chamber to remove large particles before they enter the contaminant flow electrostatic precipitator. The following discusses each of these control particles.
Because the devices to control particulate pollutants captured but not destroyed, you must have collected material properly. The solid particles have often collected from a landfill. The wastewater generated by the washers must be sent to a treatment plant wastewater. Where possible, the particulate matter collected is recycled and reused.


The management of air quality includes activities related to the protection and improvement of air quality and requires compliance with the following steps:
· Preparation of environmental health criteria and setting standards for air quality and emission standards for specific sources of pollutants
· Development of control strategies and implementation and operation of the same
The following rules are proposed national air quality:
· Standards for criteria pollutants
· Rules for the operation of new sources of pollutant emission
· Standards for issuance of hazardous air pollutants.
The national standards for air quality specified maximum permissible levels of a pollutant in a region. They are designed to protect public health and the environment from the adverse effects of air pollution.
The rules for the operation of new sources:
· Reflect the maximum reduction that can be obtained from the issuance by the best available technology
Require cost considerations and other factors of operation for its implementation.
National standards for the emission of hazardous air pollutants are designed to control pollutants for which standards do not exist or can lead to serious illness or irreversible or incapacitating reversible can increase mortality.
Control strategies
The control strategies are the actions to be undertaken in order to reduce air pollution and include the following:
a.Operación of a system for monitoring air quality. It refers to a continuous system of monitoring air quality and emissions. It is necessary to know if the sources meet the standards and whether the strategies are adequate to maintain and improve air quality.
b.Estimación existing levels of emissions of the stationary and mobile sources, and projection of future emission levels. It is based on emission inventories and regional point sources.
c.Estimación of future conditions. The estimates were done by calculating the projection of population growth, industry, transport, economy and dispersion models.
d.Determinación the degree of improvement required to meet air quality standards. It compares the current and future level of air quality, the reduction required to meet standards is estimated by models.
e.Aplicación control measures for different types of sources. It is based on available control technology and the adoption of systems of registration, licensing, testing and inspection, among others.
f.Desarrollo contingency plans for pollution episodes. The weather can lead to situations that require emergency programs.
g.Negociación with stakeholders to implement actions in emergencies. It applies to all sources for which there are emission control standards.
h.Desarrollo of long-term plans for maintaining air quality after completing the air quality standards. It considers the population and industrial growth, the calculation of expected emissions, the development of procedures for installing emissions allowed to meet future demands and to continue compliance with air quality standards.
i.Ejecución of programs to prevent significant deterioration of air quality. This refers primarily to regions where the air is cleaner than national standards established as priority regions where population and industrial development are nonexistent or minimal.
j.Aplicación of legal and coercive measures for violations of emission standards.
Traditional approaches in the management of air quality
The licensing scheme is the most common method of monitoring compliance with laws and regulations on air pollution. The purpose of the licensing system is to collect information on pollution sources, determine the success of control programs and assess future management strategies. Through the information contained in the licenses, control agencies know the location of air pollution sources, types of sources and types and amounts of emissions.
The licensing scheme is the most common method of monitoring compliance with laws and regulations on air pollution. In this mode, the air pollution sources must obtain licenses to build and operate the source.
To facilitate compliance with air pollution standards, the requirements of an industry can get together in a comprehensive license to specify all emissions generated by that source. The licenses include limitations on the emission of pollutants, compliance schedules, monitoring requirements and related provisions.
Compliance Monitoring
The compliance monitoring is a system used by regulators to determine whether there is compliance with applicable laws and regulations. The two most common types of compliance monitoring are used self-monitoring by regulated establishments and inspections to verify compliance.
The compliance monitoring includes self-monitoring and inspections. Most air pollution regulations requires regulated facilities to carry out their own monitoring to verify compliance. A typical regulation includes detailed requirements for monitoring, reporting and recording. For example, an establishment is required to monitor the performance of a control device at specific intervals using methods provided in the regulations.
Monitoring results must be reported to the regulatory agency responsible at intervals specified in the regulations. The time that a facility must maintain the records shall be specified in the regulations. An air pollution license covers all requirements for monitoring, reporting and registration to be met by the establishment.
A typical regulation includes detailed requirements for monitoring, reporting and registration. Inspections to verify compliance are another method for determining compliance. Its basic objectives are:
· Assess the compliance status of an establishment.
· Collect evidence of any specific violation of law or regulation.
• Create a visible presence of the regulator to the regulated establishment.
This "threat" inspection, together with actual inspections can help to prevent breaches of regulations by the industry.
Inspections can be regular visits to the plant, views prompted by a specific reason or follow-up to previous inspections. Ideally, each facility will inspect regulated systematically. However, no agency has control of human resources for regular inspections of all establishments under its jurisdiction. For this reason, regulatory agencies set priorities for its inspections. Theprioritization is governed by the probability that an infringement cause a risk to human health and the environment, the possibility of an industry that does not comply with the regulations and the potential that the inspection will help to deter violations. Based on these criteria, the regulator can classify all industrial establishments in priority classes. The establishments of higher priority classes are inspected more than those of lower priority classes.
Prioritization is governed by the probability that an infringement cause a risk to human health and the environment, the possibility of an industry that does not comply with the regulations and the potential that the inspection will help to deter violations. Criminalization
The penalty is to take actions against violations of environmental laws or regulations committed by a person or industry. The actions depend mainly on the seriousness and circumstances of the violation. By choosing the most appropriate penal action, the agencies generally try to achieve several goals. These goals include:
· Correct the violation as soon as possible.
· Prevent further violations.
· Be fair to the regulated community to apply similar penalties for similar offenses.
· Punish serious offenses by criminal penalties.
· Use resources effectively to enforce the laws and thus achieve the environmental and health goals with the least amount of expenditure in terms of time and money.
The regulator can issue fines for violations during a routine inspection. Private citizens may also file suit against polluters in the trial of citizens. This behavior has the potential to increase the number of prosecutions of citizens related to air pollution regulatory agencies have different penalty mechanisms ranging from informal responses such as warning letters, formal and responses to legal orders and civil or criminal action .
Innovative approaches in the management of air quality
Pollution prevention
The main goal is to prevent or reduce pollution at source. If you can not be reduced or prevented, must be recycled in an environmentally safe. If there are no workable mechanisms for prevention or recycling, emissions of pollutants must be addressed. The disposal of contaminants must be a last resort.
An example of the new emphasis on pollution prevention programs are to promote efficient use of energy for lighting. Thus, reducing electricity use and air pollution due to their generation. In the first year of implementation of this program in the United States, it was reported that has prevented the emission of 25 million kilos of carbon dioxide, 200,000 kilos of sulfur dioxide and 90,000 kilos of nitrogen dioxide.
Market-based incentives
Using market-based incentives including various forms of emissions trading. For example, industries are "broadcasting licenses" that require lower emissions or obtain new licenses from other sources. The emissions trading system gives alternatives to companies to reduce emissions more efficiently. For example, one company already has reduced its emissions below the projected level can sell their pollution license two other companies. Thus, the two companies that buy licenses have additional time to comply with emission reduction targets established by law.
Other programs have been considered based on the market. One allows the industry earn pollution credits by purchasing older polluting vehicles, the program called "cash for junk. Another program provides pollution credits to companies that acquire models that use clean fuel.
Negotiating regulations
As mentioned above, the development of a regulation requires much time and investment. One method to reduce the time and investment is the negotiation of the rules. Under this approach, the representatives of various groups meet in order to address the regulatory options for a given source of air pollution. Through the negotiation process, develops a regulation acceptable to all parties affected by the law.
Through the negotiation process develops a regulation acceptable to all parties affected by the law.

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