Air pollution

Air pollution

Air pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or damages the natural environment, into the atmosphere.

The atmosphere is a complex, dynamic natural gaseous system that is essential to support life on planet Earth. Stratospheric ozone depletion due to air pollution has long been recognized as a threat to human health as well as to the Earth's ecosystems


Pollutants


/wiki/File:Los_Angeles_Pollution.jpgLooking down from the Hollywood Hills, with Griffith Observatory on the hill in the foreground, air pollution is visible in downtown Los Angeles on a late afternoon.

In the 1960s, 70s, and 90s, the United States Congress enacted a series of Clean Air Acts which significantly strengthened regulation of air pollution. Individual U.S. states, some European nations and eventually the European Union followed these initiatives. The Clean Air Act sets numerical limits on the concentrations of a basic group of air pollutants and provide reporting and enforcement mechanisms.


In 1999, the United States EPA replaced the Pollution Standards Index (PSI) with the Air Quality Index (AQI) to incorporate new PM2.5 and Ozone standards.


The effects of these laws have been very positive. In the United States between 1970 and 2006, citizens enjoyed the following reductions in annual pollution emissions:


·carbon monoxide emissions fell from 197 million tons to 89 million tons

·nitrogen oxide emissions fell from 27 million tons to 19 million tons

·sulfur dioxide emissions fell from 31 million tons to 15 million tons

·particulate emissions fell by 80%

·lead emissions fell by more than 98%

In an October 2006 letter to EPA, the agency's independent scientific advisors warned that the ozone smog standard “needs to be substantially reduced” and that there is “no scientific justification” for retaining the current, weaker standard. The scientists unanimously recommended a smog threshold of 60 to 70 ppb after they conducted an extensive review of the evidence.

The EPA has proposed, in June 2007, a new threshold of 75 ppb. This is less strict than the scientific recommendation, but is more strict than the current standard.

Some industries are lobbying to keep the current standards in place. Environmentalists and public health advocates are mobilizing to support the scientific recommendations.[citation needed]

The National Ambient Air Quality Standards are pollution thresholds which trigger mandatory remediation plans by state and local governments, subject to enforcement by the EPA.

An outpouring of dust layered with man-made sulfates, smog, industrial fumes, carbon grit, and nitrates is crossing the Pacific Ocean on prevailing winds from booming Asian economies in plumes so vast they alter the climate. Almost a third of the air over Los Angeles and San Francisco can be traced directly to Asia. With it comes up to three-quarters of the black carbon particulate pollution that reaches the West Coast. Libertarians typically suggest propertarian methods of stopping pollution. They advocate strict liability which would hold accountable anyone who causes polluted air to emanate into someone else's airspace. This offense would be considered aggression, and damages could be sought in court under the common law, possibly through class action suits.Since in a libertarian society, highways would be privatized under a system of free market roads, the highway owners would also be held liable for pollution emanating from vehicles traveling along their property. This would give them a financial incentive to keep the worst polluters off of their roads.

Most polluted cities

Air pollution is usually concentrated in densely populated metropolitan areas, especially in developing countries where environmental regulations are relatively lax or nonexistent. However, even populated areas in developed countries attain unhealthy levels of pollution.


Carbon dioxide emissions
Most Polluted World Cities by PM
Particulatematter,μg/m³ (2004) City
169 Cairo, Egypt
150 Delhi, India
128 Kolkata, India (Calcutta)
125 Tianjin, China
123 Chongqing, China
109 Kanpur, India
109 Lucknow, India
104 Jakarta, Indonesia
101 Shenyang, China
Total CO2 emissions

Main article: List of countries by carbon dioxide emissions
Countries with the highest CO2 emissions
Country Carbon dioxide emissions peryear (106 Tons) (2006) Percentage of global total
China 6,103 21.5%
United States 5,752 20.2%
Russia 1,564 5.5%
India 1,510 5.3%
Japan 1293 4.6%
Germany 805 2.8%
United Kingdom 568 2.0%
Canada 544 1.9%
South Korea 475 1.7%
Italy 474 1.7%
Per capita CO2 emissions

Main article: List of countries by carbon dioxide emissions per capita
Countries with the highest per capita CO2 emissions
Country Carbon dioxide emissions per year(Tons per person) (2006)
Qatar 56.2
United Arab Emirates 32.8
Kuwait 31.2
Bahrain 28.8
Trinidad and Tobago 25.3
Luxembourg 24.5
Netherlands Antilles 22.8
Aruba 22.3
United States 19
Australia 18.1

Atmospheric dispersion

Main article: Atmospheric dispersion modeling
The basic technology for analyzing air pollution is through the use of a variety of mathematical models for predicting the transport of air pollutants in the lower atmosphere. The principal methodologies are:

·Point source dispersion, used for industrial source
.
·Line source dispersion, used for airport and roadway air dispersion modeling

·Area source dispersion, used for forest fires or duststorms

·Photochemical models, used to analyze reactive pollutants that form smog

/wiki/File:Gaussian_Plume.png

/wiki/File:Gaussian_Plume.pngVisualization of a buoyant Gaussian air pollution dispersion plume as used in many atmospheric dispersion models

The point source problem is the best understood, since it involves simpler mathematics and has been studied for a long period of time, dating back to about the year 1900. It uses a Gaussian dispersion model for buoyant pollution plumes to forecast the air pollution isopleths, with consideration given to wind velocity, stack height, emission rate and stability class (a measure of atmospheric turbulence).[50][51] This model has been extensively validated and calibrated with experimental data for all sorts of atmospheric conditions.

The roadway air dispersion model was developed starting in the late 1950s and early 1960s in response to requirements of the National Environmental Policy Act and the U.S. Department of Transportation (then known as the Federal Highway Administration) to understand impacts of proposed new highways upon air quality, especially in urban areas. Several research groups were active in this model development, among which were: the Environmental Research and Technology (ERT) group in Lexington, Massachusetts, the ESL Inc. group in Sunnyvale, California and the California Air Resources Board group in Sacramento, California. The research of the ESL group received a boost with a contract award from the United States Environmental Protection Agency to validate a line source model using sulfur hexafluoride as a tracer gas. This program was successful in validating the line source model developed by ESL inc. Some of the earliest uses of the model were in court cases involving highway air pollution, the Arlington, Virginia portion of Interstate 66 and the New Jersey Turnpike widening project through East Brunswick, New Jersey.

Area source models were developed in 1971 through 1974 by the ERT and ESL groups, but addressed a smaller fraction of total air pollution emissions, so that their use and need was not as widespread as the line source model, which enjoyed hundreds of different applications as early as the 1970s. Similarly photochemical models were developed primarily in the 1960s and 1970s, but their use was more specialized and for regional needs, such as understanding smog formation in Los Angeles, California.


Environmental impacts of greenhouse gas pollutants

Main articles: Ocean acidification and Greenhouse effect
The greenhouse effect is a phenomenon whereby greenhouse gases create a condition in the upper atmosphere causing a trapping of heat and leading to increased surface and lower tropospheric temperatures. Carbon dioxide from combustion of fossil fuels is the major problem. Other greenhouse gases include methane, hydrofluorocarbons, perfluorocarbons, chlorofluorocarbons, nitrogen oxides, and ozone.

This effect has been understood by scientists for about a century, and technological advancements during this period have helped increase the breadth and depth of data relating to the phenomenon. Currently, scientists are studying the role of changes in composition of greenhouse gases from natural and anthropogenic sources for the effect on climate change.

A number of studies have also investigated the potential for long-term rising levels of atmospheric carbon dioxide to cause increases in the acidity of ocean waters and the possible effects of this on marine ecosystems.


Most polluted cities
Air pollution is usually concentrated in densely populated metropolitan areas, especially in developing countries where environmental regulations are relatively lax or nonexistent. However, even populated areas in developed countries attain unhealthy levels of pollution.


Carbon dioxide emissions
Most Polluted World Cities by PM[48]
Particulatematter,μg/m³ (2004) City
169 Cairo, Egypt
150 Delhi, India
128 Kolkata, India (Calcutta)
125 Tianjin, China
123 Chongqing, China
109 Kanpur, India
109 Lucknow, India
104 Jakarta, Indonesia
101 Shenyang, China
Total CO2 emissions

Main article: List of countries by carbon dioxide emissions
Countries with the highest CO2 emissions
Country Carbon dioxide emissions peryear (106 Tons) (2006) Percentage of global total
China 6,103 21.5%
United States 5,752 20.2%
Russia 1,564 5.5%
India 1,510 5.3%
Japan 1293 4.6%
Germany 805 2.8%
United Kingdom 568 2.0%
Canada 544 1.9%
South Korea 475 1.7%
Italy 474 1.7%
Per capita CO2 emissions

Main article: List of countries by carbon dioxide emissions per capita
Countries with the highest per capita CO2 emissions
Country Carbon dioxide emissions per year(Tons per person) (2006)
Qatar 56.2
United Arab Emirates 32.8
Kuwait 31.2
Bahrain 28.8
Trinidad and Tobago 25.3
Luxembourg 24.5
Netherlands Antilles 22.8
Aruba 22.3
United States 19
Australia 18.1

Atmospheric dispersion

Main article: Atmospheric dispersion modeling


The basic technology for analyzing air pollution is through the use of a variety of mathematical models for predicting the transport of air pollutants in the lower atmosphere. The principal methodologies are:

·Point source dispersion, used for industrial sources.
·Line source dispersion, used for airport and roadway air dispersion modeling
·Area source dispersion, used for forest fires or duststorms

·Photochemical models, used to analyze reactive pollutants that form smog

/wiki/File:Gaussian_Plume.png

/wiki/File:Gaussian_Plume.pngVisualization of a buoyant Gaussian air pollution dispersion plume as used in many atmospheric dispersion models

The point source problem is the best understood, since it involves simpler mathematics and has been studied for a long period of time, dating back to about the year 1900. It uses a Gaussian dispersion model for buoyant pollution plumes to forecast the air pollution isopleths, with consideration given to wind velocity, stack height, emission rate and stability class (a measure of atmospheric turbulence).[50][51] This model has been extensively validated and calibrated with experimental data for all sorts of atmospheric conditions.

The roadway air dispersion model was developed starting in the late 1950s and early 1960s in response to requirements of the National Environmental Policy Act and the U.S. Department of Transportation (then known as the Federal Highway Administration) to understand impacts of proposed new highways upon air quality, especially in urban areas. Several research groups were active in this model development, among which were: the Environmental Research and Technology (ERT) group in Lexington, Massachusetts, the ESL Inc. group in Sunnyvale, California and the California Air Resources Board group in Sacramento, California. The research of the ESL group received a boost with a contract award from the United States Environmental Protection Agency to validate a line source model using sulfur hexafluoride as a tracer gas. This program was successful in validating the line source model developed by ESL inc. Some of the earliest uses of the model were in court cases involving highway air pollution, the Arlington, Virginia portion of Interstate 66 and the New Jersey Turnpike widening project through East Brunswick, New Jersey.

Area source models were developed in 1971 through 1974 by the ERT and ESL groups, but addressed a smaller fraction of total air pollution emissions, so that their use and need was not as widespread as the line source model, which enjoyed hundreds of different applications as early as the 1970s. Similarly photochemical models were developed primarily in the 1960s and 1970s, but their use was more specialized and for regional needs, such as understanding smog formation in Los Angeles, California.


Environmental impacts of greenhouse gas pollutants
Main articles: Ocean acidification and Greenhouse effect

The greenhouse effect is a phenomenon whereby greenhouse gases create a condition in the upper atmosphere causing a trapping of heat and leading to increased surface and lower tropospheric temperatures. Carbon dioxide from combustion of fossil fuels is the major problem. Other greenhouse gases include methane, hydrofluorocarbons, perfluorocarbons, chlorofluorocarbons, nitrogen oxides, and ozone.

This effect has been understood by scientists for about a century, and technological advancements during this period have helped increase the breadth and depth of data relating to the phenomenon. Currently, scientists are studying the role of changes in composition of greenhouse gases from natural and anthropogenic sources for the effect on climate change.

A number of studies have also investigated the potential for long-term rising levels of atmospheric carbon dioxide to cause increases in the acidity of ocean waters and the possible effects of this on marine ecosystems.



Most polluted cities

Air pollution is usually concentrated in densely populated metropolitan areas, especially in developing countries where environmental regulations are relatively lax or nonexistent. However, even populated areas in developed countries attain unhealthy levels of pollution.



Carbon dioxide emissions
Most Polluted World Cities by PM
Particulatematter,μg/m³ (2004) City
169 Cairo, Egypt
150 Delhi, India
128 Kolkata, India (Calcutta)
125 Tianjin, China
123 Chongqing, China
109 Kanpur, India
109 Lucknow, India
104 Jakarta, Indonesia
101 Shenyang, China
Total CO2 emissions


Main article: List of countries by carbon dioxide emissions

Countries with the highest CO2 emissions
Country Carbon dioxide emissions peryear (106 Tons) (2006) Percentage of global total
China 6,103 21.5%
United States 5,752 20.2%
Russia 1,564 5.5%
India 1,510 5.3%
Japan 1293 4.6%
Germany 805 2.8%
United Kingdom 568 2.0%
Canada 544 1.9%
South Korea 475 1.7%
Italy 474 1.7%
Per capita CO2 emissions

Main article: List of countries by carbon dioxide emissions per capita

Countries with the highest per capita CO2 emissions
Country Carbon dioxide emissions per year(Tons per person) (2006)
Qatar 56.2
United Arab Emirates 32.8
Kuwait 31.2
Bahrain 28.8
Trinidad and Tobago 25.3
Luxembourg 24.5
Netherlands Antilles 22.8
Aruba 22.3
United States 19
Australia 18.1

Atmospheric dispersion

Main article: Atmospheric dispersion modeling
The basic technology for analyzing air pollution is through the use of a variety of mathematical models for predicting the transport of air pollutants in the lower atmosphere. The principal methodologies are:

·Point source dispersion, used for industrial sources.

·Line source dispersion, used for airport and roadway air dispersion modeling

·Area source dispersion, used for forest fires or duststorms

·Photochemical models, used to analyze reactive pollutants that form smog

/wiki/File:Gaussian_Plume.png
/wiki/File:Gaussian_Plume.pngVisualization of a buoyant Gaussian air pollution dispersion plume as used in many atmospheric dispersion models

The point source problem is the best understood, since it involves simpler mathematics and has been studied for a long period of time, dating back to about the year 1900. It uses a Gaussian dispersion model for buoyant pollution plumes to forecast the air pollution isopleths, with consideration given to wind velocity, stack height, emission rate and stability class (a measure of atmospheric turbulence).[50][51] This model has been extensively validated and calibrated with experimental data for all sorts of atmospheric conditions.

The roadway air dispersion model was developed starting in the late 1950s and early 1960s in response to requirements of the National Environmental Policy Act and the U.S. Department of Transportation (then known as the Federal Highway Administration) to understand impacts of proposed new highways upon air quality, especially in urban areas. Several research groups were active in this model development, among which were: the Environmental Research and Technology (ERT) group in Lexington, Massachusetts, the ESL Inc. group in Sunnyvale, California and the California Air Resources Board group in Sacramento, California. The research of the ESL group received a boost with a contract award from the United States Environmental Protection Agency to validate a line source model using sulfur hexafluoride as a tracer gas. This program was successful in validating the line source model developed by ESL inc. Some of the earliest uses of the model were in court cases involving highway air pollution, the Arlington, Virginia portion of Interstate 66 and the New Jersey Turnpike widening project through East Brunswick, New Jersey.

Area source models were developed in 1971 through 1974 by the ERT and ESL groups, but addressed a smaller fraction of total air pollution emissions, so that their use and need was not as widespread as the line source model, which enjoyed hundreds of different applications as early as the 1970s. Similarly photochemical models were developed primarily in the 1960s and 1970s, but their use was more specialized and for regional needs, such as understanding smog formation in Los Angeles, California.


Environmental impacts of greenhouse gas pollutants

Main articles: Ocean acidification and Greenhouse effect

The greenhouse effect is a phenomenon whereby greenhouse gases create a condition in the upper atmosphere causing a trapping of heat and leading to increased surface and lower tropospheric temperatures. Carbon dioxide from combustion of fossil fuels is the major problem. Other greenhouse gases include methane, hydrofluorocarbons, perfluorocarbons, chlorofluorocarbons, nitrogen oxides, and ozone.

This effect has been understood by scientists for about a century, and technological advancements during this period have helped increase the breadth and depth of data relating to the phenomenon. Currently, scientists are studying the role of changes in composition of greenhouse gases from natural and anthropogenic sources for the effect on climate change.

A number of studies have also investigated the potential for long-term rising levels of atmospheric carbon dioxide to cause increases in the acidity of ocean waters and the possible effects of this on marine ecosystems.

Most polluted cities
Air pollution is usually concentrated in densely populated metropolitan areas, especially in developing countries where environmental regulations are relatively lax or nonexistent. However, even populated areas in developed countries attain unhealthy levels of pollution.

Carbon dioxide emissions

Most Polluted World Cities by PM
Particulatematter,μg/m³ (2004) City
169 Cairo, Egypt
150 Delhi, India
128 Kolkata, India (Calcutta)
125 Tianjin, China
123 Chongqing, China
109 Kanpur, India
109 Lucknow, India
104 Jakarta, Indonesia
101 Shenyang, China
Total CO2 emissions

Main article: List of countries by carbon dioxide emissions

Countries with the highest CO2 emissions
Country Carbon dioxide emissions peryear (106 Tons) (2006) Percentage of global total
China 6,103 21.5%
United States 5,752 20.2%
Russia 1,564 5.5%
India 1,510 5.3%
Japan 1293 4.6%
Germany 805 2.8%
United Kingdom 568 2.0%
Canada 544 1.9%
South Korea 475 1.7%
Italy 474 1.7%
Per capita CO2 emissions
Main article: List of countries by carbon dioxide emissions per capita
Countries with the highest per capita CO2 emissions

Country Carbon dioxide emissions per year(Tons per person) (2006)

Qatar 56.2
United Arab Emirates32.8
Kuwait 31.2
Bahrain 28.8
Trinidad and Tobago 25.3
Luxembourg 24.5
Netherlands Antilles 22.8
Aruba 22.3
United States 19
Australia 18.1

Atmospheric dispersion


Main article: Atmospheric dispersion modeling

The basic technology for analyzing air pollution is through the use of a variety of mathematical models for predicting the transport of air pollutants in the lower atmosphere. The principal methodologies are:

·Point source dispersion, used for industrial sources.

·Line source dispersion, used for airport and roadway air dispersion modeling

·Area source dispersion, used for forest fires or duststorms

·Photochemical models, used to analyze reactive pollutants that form smog
/wiki/File:Gaussian_Plume.png

/wiki/File:Gaussian_Plume.pngVisualization of a buoyant Gaussian air pollution dispersion plume as used in many atmospheric dispersion models


The point source problem is the best understood, since it involves simpler mathematics and has been studied for a long period of time, dating back to about the year 1900. It uses a Gaussian dispersion model for buoyant pollution plumes to forecast the air pollution isopleths, with consideration given to wind velocity, stack height, emission rate and stability class (a measure of atmospheric turbulence).This model has been extensively validated and calibrated with experimental data for all sorts of atmospheric conditions.

The roadway air dispersion model was developed starting in the late 1950s and early 1960s in response to requirements of the National Environmental Policy Act and the U.S. Department of Transportation (then known as the Federal Highway Administration) to understand impacts of proposed new highways upon air quality, especially in urban areas. Several research groups were active in this model development, among which were: the Environmental Research and Technology (ERT) group in Lexington, Massachusetts, the ESL Inc. group in Sunnyvale, California and the California Air Resources Board group in Sacramento, California. The research of the ESL group received a boost with a contract award from the United States Environmental Protection Agency to validate a line source model using sulfur hexafluoride as a tracer gas. This program was successful in validating the line source model developed by ESL inc. Some of the earliest uses of the model were in court cases involving highway air pollution, the Arlington, Virginia portion of Interstate 66 and the New Jersey Turnpike widening project through East Brunswick, New Jersey.

Area source models were developed in 1971 through 1974 by the ERT and ESL groups, but addressed a smaller fraction of total air pollution emissions, so that their use and need was not as widespread as the line source model, which enjoyed hundreds of different applications as early as the 1970s. Similarly photochemical models were developed primarily in the 1960s and 1970s, but their use was more specialized and for regional needs, such as understanding smog formation in Los Angeles, California.

Environmental impacts of greenhouse gas pollutants

Main articles: Ocean acidification and Greenhouse effect

The greenhouse effect is a phenomenon whereby greenhouse gases create a condition in the upper atmosphere causing a trapping of heat and leading to increased surface and lower tropospheric temperatures. Carbon dioxide from combustion of fossil fuels is the major problem. Other greenhouse gases include methane, hydrofluorocarbons, perfluorocarbons, chlorofluorocarbons, nitrogen oxides, and ozone.

This effect has been understood by scientists for about a century, and technological advancements during this period have helped increase the breadth and depth of data relating to the phenomenon. Currently, scientists are studying the role of changes in composition of greenhouse gases from natural and anthropogenic sources for the effect on climate change.

A number of studies have also investigated the potential for long-term rising levels of atmospheric carbon dioxide to cause increases in the acidity of ocean waters and the possible effects of this on marine ecosystems.
Atmospheric dispersion
Main article: Atmospheric dispersion modeling

The basic technology for analyzing air pollution is through the use of a variety of mathematical models for predicting the transport of air pollutants in the lower atmosphere. The principal methodologies are:

·Point source dispersion, used for industrial sources.

·Line source dispersion, used for airport and roadway air dispersion modeling

·Area source dispersion, used for forest fires or duststorms


·Photochemical models, used to analyze reactive pollutants that form smog
/wiki/File:Gaussian_Plume.png

/wiki/File:Gaussian_Plume.pngVisualization of a buoyant Gaussian air pollution dispersion plume as used in many atmospheric dispersion models

The point source problem is the best understood, since it involves simpler mathematics and has been studied for a long period of time, dating back to about the year 1900. It uses a Gaussian dispersion model for buoyant pollution plumes to forecast the air pollution isopleths, with consideration given to wind velocity, stack height, emission rate and stability class (a measure of atmospheric turbulence).[50][51] This model has been extensively validated and calibrated with experimental data for all sorts of atmospheric conditions.

The roadway air dispersion model was developed starting in the late 1950s and early 1960s in response to requirements of the National Environmental Policy Act and the U.S. Department of Transportation (then known as the Federal Highway Administration) to understand impacts of proposed new highways upon air quality, especially in urban areas. Several research groups were active in this model development, among which were: the Environmental Research and Technology (ERT) group in Lexington, Massachusetts, the ESL Inc. group in Sunnyvale, California and the California Air Resources Board group in Sacramento, California. The research of the ESL group received a boost with a contract award from the United States Environmental Protection Agency to validate a line source model using sulfur hexafluoride as a tracer gas. This program was successful in validating the line source model developed by ESL inc. Some of the earliest uses of the model were in court cases involving highway air pollution, the Arlington, Virginia portion of Interstate 66 and the New Jersey Turnpike widening project through East Brunswick, New Jersey.

Area source models were developed in 1971 through 1974 by the ERT and ESL groups, but addressed a smaller fraction of total air pollution emissions, so that their use and need was not as widespread as the line source model, which enjoyed hundreds of different applications as early as the 1970s. Similarly photochemical models were developed primarily in the 1960s and 1970s, but their use was more specialized and for regional needs, such as understanding smog formation in Los Angeles, California.

Environmental impacts of greenhouse gas pollutants
Main articles: Ocean acidification and Greenhouse effect
The greenhouse effect is a phenomenon whereby greenhouse gases create a condition in the upper atmosphere causing a trapping of heat and leading to increased surface and lower tropospheric temperatures. Carbon dioxide from combustion of fossil fuels is the major problem. Other greenhouse gases include methane, hydrofluorocarbons, perfluorocarbons, chlorofluorocarbons, nitrogen oxides, and ozone.

This effect has been understood by scientists for about a century, and technological advancements during this period have helped increase the breadth and depth of data relating to the phenomenon. Currently, scientists are studying the role of changes in composition of greenhouse gases from natural and anthropogenic sources for the effect on climate change.

A number of studies have also investigated the potential for long-term rising levels of atmospheric carbon dioxide to cause increases in the acidity of ocean waters and the possible effects of this on marine ecosystems