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Air Pollution

The health effects of China’s serious air pollution are an issue of enormous public concern and the government has been rolling out a series of policies to grapple with it. But the complexity of the problem and the difficult tradeoffs associated with various policy options are not often fully understood. This wiki draws on information from across the natural, medical and social sciences to provide information on the nature and causes of air pollution in China and current policies to address it. It also provides links to further resources. The wiki will evolve as we add contributions from experts in the FORHEAD network If you would like to be notified of updates, please sign up here. If you have suggestions for other topics, please contact us at forhead@forhead.org

Air Pollution

People often use the term “air pollution” as if it describes a single environmental hazard, one with an obvious solution: controlling the pollution at the source. One observes that the air outside the window is hazy, for instance...Read more

Pollutants are concerned for air pollution

To broaden understanding of air quality challenges, a sensible starting point is to emphasize first that air pollution is made up of a number of distinct pollutants, focusing on those of greatest concern:particles (also called particulate matter, TSP/PM2.5/PM10,Sulfur dioxide (SO2),nitrogen oxides (NOx),ground-level ozone (O3),Monoxide (CO), Lead (Pb),and Ammonia.

Health effects of PM 2.5/PM10

Particles under 10 micrometers in diameter can pass through the nose and throat to enter the lungs, with the smallest ones-PM2.5 and even smaller size fractions-penetrating most deeply and even entering the especially PM2.5 exposures to sever health impacts, including premature death (particularly in those with heart or lung disease), cardiovascular disease such as heart attacks and irregular heart beat, respiratory diseases, and lung cancer. It is important to note that PM is different from air pollutants in that it is defined only by physical characteristics – its size. Other pollutants are defined by their chemistry (as reflected in their molecular notation, such as SO2). But PM2.5 or PM10 can have any chemical composition at all, as long as it takes solid and/or liquid form, is suspended in the air, and meets the given size threshold. This fact hints at how far scientific understanding still has to go in understanding PM2.5 formations, its health effects, and the difficulty of its control.

What is air pollution?

People often use the term “air pollution” as if it describes a single environmental hazard, one with an obvious solution: controlling the pollution at the source. One observes that the air outside the window is hazy, for instance, or sees on a Smartphone that an Air Quality Index is high, and wonders why this noxious problem was not prevented, at the source, before it could develop. Unfortunately, the nature of air pollution is many times more complex than this casual perception recognizes… Many factors influence air quality problems also change: the size and structure of the economy, the energy mix, technologies of both combustion and control, settlement patterns, lifestyle choices, and much more… Air pollution is a chemical and physical phenomenon that takes place in the atmosphere of one of the most complex systems humanity has ever sought to understand (the Earth). The sources of pollution are numerous and environmental engineers have to continually test and improve inventories of emissions across highly complex and changing economies and natural systems…

What is air pollution?

People often use the term “air pollution” as if it describes a single environmental hazard, one with an obvious solution: controlling the pollution at the source. One observes that the air outside the window is hazy, for instance, or sees on a Smartphone that an Air Quality Index is high, and wonders why this noxious problem was not prevented, at the source, before it could develop. Unfortunately, the nature of air pollution is many times more complex than this casual perception recognizes… Many factors influence air quality problems also change: the size and structure of the economy, the energy mix, technologies of both combustion and control, settlement patterns, lifestyle choices, and much more… Air pollution is a chemical and physical phenomenon that takes place in the atmosphere of one of the most complex systems humanity has ever sought to understand (the Earth). The sources of pollution are numerous and environmental engineers have to continually test and improve inventories of emissions across highly complex and changing economies and natural systems…

Health effects of SO2

Exposure SO2 has been shown to cause respiratory illnesses aggravation of cardiovascular and respiratory disease in people who already have it. The largest overall health risk of SO2, however, is almost certainly as a precursor gas that reacts with other gases to form sulfate particles, a major form of the secondary PM2.5.

EHealth effects of Ground level ozone

Exposure of Ozone cause a variety of adverse effects in the respiratory system, particularly in children, the elderly, and people with lung disease, and an association with [premature death has now been shown. Ozone also diminishes the productivity of many vegetation types during the growing season…..

Health effects of NOx

Exposure to gaseous NO2 irritates the respiratory system and can increase or induce asthma symptoms, but like so2 the total health impacts of NOx are likely dominated by its roles as precursor to other, secondary air pollutants. These importantly include another type of PM2.5, nitrates, as well as ground-level ozone. Also like SO2, NOx is a source of the acidic compounds that cause acid rain through secondary chemistry.

Health effects of carbon monoxide

When inhaled CO is absorbed by hemoglobin in the blood, limiting oxygen delivery to the organs and tissues of the body, and can cause shortness of breath, dizziness, and at extremely high levels, death. Ambient levels of CO are rarely high enough to cause adverse health effects, except in particular circumstances such as confined areas where combustion is taking place.

Health effects of Lead

Lead is a heavy metal that, when inhaled or otherwise ingested, becomes distributed throughout the body by the bloodstream. It can affect many critical bodily systems including the nervous system, and is especially associated with severe neurological effects in children.

Health effects of VOC

The VOCs can contribute to ozone. And they are also a precursor to one of the largest categories of secondary PM2.5, called secondary organic aerosols. And it their primary, gaseous form, VOCs can cause diverse health effects, though this occurs especially through exposure to high concentrations in confined spaces, particularly indoors.

Ammonia

Ammonia is another important precursor to PM2.5 in China, which reacts with SO2 or NOx to produce ammonium sulfate or ammonium nitrate fine particles. Ammonia is rarely even recognized as an air pollutant, perhaps because its leading sources are agricultural-livestock farming and fertilizer use-and therefore unlike the industrial and/or combustion processes that most associate with air pollution.

Industries:


Coal-fired power plants
Steel and Iron
Cement
Other industrial boilers

Cement Industry

China produced 58% of the world’s cement in 2013, making it the world’s largest market. As the primary material used to make concrete for buildings and roads, cement use has increased in tandem with China’s economic growth...Read more

Emissions Standards Emissions standards indicate the maximum amount of criteria pollutants that are permitted per unit of production and are set on an industry basis. Most standards are national but in some instances, regionally specific standards may be set by the national government. Localities may also set standards that are tighter than the national ones. Emissions standards are set by industry for the power, cement, etc. sectors .
GHGs
Gases that trap heat in the atmosphere are called greenhouse gases. This section provides information on emissions and removals of the main greenhouse gases to and from the atmosphere.
• Carbon dioxide (CO2) : Carbon dioxide enters the atmosphere through burning fossil fuels (coal, natural gas and oil), solid waste, trees and wood products, and also as a result of certain chemical reactions (e.g., manufacture of cement). Carbon dioxide is removed from the atmosphere (or "sequestered") when it is absorbed by plants as part of the biological carbon cycle.
• Methane (CH4) : Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from livestock and other agricultural practices and by the decay of organic waste in municipal solid waste landfills.
• Nitrous oxide (N2O) : Nitrous oxide is emitted during agricultural and industrial activities, as well as during combustion of fossil fuels and solid waste.
• Fluorinated gases : Hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride, and nitrogen trifluoride are synthetic, powerful greenhouse gases that are emitted from a variety of industrial processes. Fluorinated gases are sometimes used as substitutes for stratospheric ozone-depleting substances (e.g., chlorofluorocarbons, hydrochlorofluorocarbons, and halons). These gases are typically emitted in smaller quantities, but because they are potent greenhouse gases, they are sometimes referred to as High Global Warming Potential gases ("High GWP gases"). The primary sources of greenhouse gas emissions in the United States are:
• Electricity production (30% of 2014 greenhouse gas emissions) - Electricity production generates the largest share of greenhouse gas emissions. Approximately 67% of our electricity comes from burning fossil fuels, mostly coal and natural gas.[2]
• Transportation (26% of 2014 greenhouse gas emissions) - Greenhouse gas emissions from transportation primarily come from burning fossil fuel for our cars, trucks, ships, trains, and planes. Over 90% of the fuel used for transportation is petroleum based, which includes gasoline and diesel.[3]
• Industry (21% of 2014 greenhouse gas emissions) - Greenhouse gas emissions from industry primarily come from burning fossil fuels for energy as well as greenhouse gas emissions from certain chemical reactions necessary to produce goods from raw materials.
• Commercial and Residential (12% of 2014 greenhouse gas emissions) - Greenhouse gas emissions from businesses and homes arise primarily from fossil fuels burned for heat, the use of certain products that contain greenhouse gases, and the handling of waste.
• Agriculture (9% of 2014 greenhouse gas emissions) - Greenhouse gas emissions from agriculture come from livestock such as cows, agricultural soils, and rice production
• Land Use and Forestry (offset of 11% of 2014 greenhouse gas emissions) - Land areas can act as a sink (absorbing CO2 from the atmosphere) or a source of greenhouse gas emissions. In the United States, since 1990, managed forests and other lands have absorbed more CO2 from the atmosphere than they emit.
How are emissions levels calculated?
Ideally, actual emissions from every individual pollution source would be monitored. But in practice this is impossible when there are multiple different sources which may be increasing or decreasing in number, or changing their location. Emissions from activities that are illegal (for example burning of agricultural stubble or household waste in rural areas, or from small, unregistered industries and businesses in urban areas) can be extremely hard to monitor. As a result, only emissions from a limited number of sources, usually large industrial and power plants “above a certain scale” (规模以上)are actually monitored, sometimes with automatic online reporting to the Ministry of Environmental Protection. Emissions from other sources are estimated in one of two ways: either by using inventories, or by testing air quality and tracing pollutants to their sources. The second method only works well for pollutants that are produced by a limited number of sources. GIVE EXAMPLE. Statistical methods are used to factor in the different levels of uncertainty associated with estimating Activity Levels for different industries. Note Provincial level data on energy use does not match national data, which usually gives lower figures. This may be because provincial data captures smaller plants and mines or because national is revised downward (NBS privately acknowledges this). Provincial data is probably more reliable.
Inventories of pollution sources
Pollution Inventories are compiled based on Activity Levels, which are either the amount of energy consumed or the amount of a particular product that is produced.
The Emissions Factor is the amount of a criteria pollutant emitted per unit of energy consumed or unit of production.
Four main sectors are included in pollution inventories:
• Coal-fired power plants (CPP)
• Industry (IND)
• Transportation (TRA), including on-road and non-road sources)
• Residential & commercial activities (RES), including fossil fuel use, biofuel use, and open burning of crop residue biomass).
These categories are further subdivided. For example, Industry is subdivided into
• Cement plants (CEM),
• Iron & steel plants (ISP)
• Other industrial boilers (OIB, including oil power plants as well),
• Other processes (PRO)
To avoid double counting, only direct emissions from each sector are estimated. For example, emissions from electricity generation used in steel making are included in the Emissions Factor for Coal-fired Power Plants but not for Iron and Steel Plants..
Calculating emissions from each of these sectors involves multiple stages and is very complex. Some examples of data sources and methods of estimating Activity Levels and related emissions are given below.
Official monitored data: Emissions have resulted in high level of pollution measured by the government in the major cities of China. Most policy-oriented analysis of China’s air pollution rely on data from the government’s extensive network of urban monitoring stations, chiefly operated by municipal Environmental Protection Bureaus (EPBs) with data compiled and reported by the Chinese National Environmental Monitoring Center. Such data are collected, analyzed, and reported chiefly for regulatory purposes, as indicators of the progress of pollution control efforts, for guiding air pollution management, and for public communication. (Clear skies over China, 1.4.3, page 19) In recent years, the concentrations of three pollutants have been monitored and reported as daily averages on websites, and as annual averages in published sources: SO2, particulate matter (TSP until 2000, switching to PM10 thereafter), nitrogen oxides (NOx until 1999, NO2 thereafter). Ozone and carbon monoxide (CO) were added to China’s national urban air measurement standards, in 20011, and PM2.5 was added for major cities and key regions in 2012. (Clear skies over China, 1.4.3, page 21) Official monitoring data are almost always reported in aggregated terms, both temporally (such as daily means) and spatially (such as the average of all stations in a city). The nature of the instrumentation and the methods of measurement are rarely specified, limiting the interpretation. (Clear skies over China, 1.5.2, page 28-29) Independent scientific observations: There are three main sources of independent scientific observations of air pollution or GHG levels in China. They are by instruments that are deployed 1. at the surface, at permanent stations or in short-term field campaigns; 2. In the air, on aircraft or balloons; 3. In space, onboard satellites. (Clear skies over China, 1.5.2, page 29)
How are emissions levels calculated?
Ideally, actual emissions from every individual pollution source would be monitored. But in practice this is impossible when there are multiple different sources which may be increasing or decreasing in number, or changing their location. Emissions from activities that are illegal (for example burning of agricultural stubble or household waste in rural areas, or from small, unregistered industries and businesses in urban areas) can be extremely hard to monitor. As a result, only emissions from a limited number of sources, usually large industrial and power plants “above a certain scale” (规模以上)are actually monitored, sometimes with automatic online reporting to the Ministry of Environmental Protection. Emissions from other sources are estimated in one of two ways: either by using inventories, or by testing air quality and tracing pollutants to their sources. The second method only works well for pollutants that are produced by a limited number of sources. GIVE EXAMPLE. Statistical methods are used to factor in the different levels of uncertainty associated with estimating Activity Levels for different industries. Note Provincial level data on energy use does not match national data, which usually gives lower figures. This may be because provincial data captures smaller plants and mines or because national is revised downward (NBS privately acknowledges this). Provincial data is probably more reliable.
GHGs
Gases that trap heat in the atmosphere are called greenhouse gases. This section provides information on emissions and removals of the main greenhouse gases to and from the atmosphere.
• Carbon dioxide (CO2) : Carbon dioxide enters the atmosphere through burning fossil fuels (coal, natural gas and oil), solid waste, trees and wood products, and also as a result of certain chemical reactions (e.g., manufacture of cement). Carbon dioxide is removed from the atmosphere (or "sequestered") when it is absorbed by plants as part of the biological carbon cycle.
• Methane (CH4) : Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from livestock and other agricultural practices and by the decay of organic waste in municipal solid waste landfills.
• Nitrous oxide (N2O) : Nitrous oxide is emitted during agricultural and industrial activities, as well as during combustion of fossil fuels and solid waste.
• Fluorinated gases : Hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride, and nitrogen trifluoride are synthetic, powerful greenhouse gases that are emitted from a variety of industrial processes. Fluorinated gases are sometimes used as substitutes for stratospheric ozone-depleting substances (e.g., chlorofluorocarbons, hydrochlorofluorocarbons, and halons). These gases are typically emitted in smaller quantities, but because they are potent greenhouse gases, they are sometimes referred to as High Global Warming Potential gases ("High GWP gases").
The primary sources of greenhouse gas emissions in the United States are:
• Electricity production (30% of 2014 greenhouse gas emissions) - Electricity production generates the largest share of greenhouse gas emissions. Approximately 67% of our electricity comes from burning fossil fuels, mostly coal and natural gas.[2]
• Transportation (26% of 2014 greenhouse gas emissions) - Greenhouse gas emissions from transportation primarily come from burning fossil fuel for our cars, trucks, ships, trains, and planes. Over 90% of the fuel used for transportation is petroleum based, which includes gasoline and diesel.[3]
• Industry (21% of 2014 greenhouse gas emissions) - Greenhouse gas emissions from industry primarily come from burning fossil fuels for energy as well as greenhouse gas emissions from certain chemical reactions necessary to produce goods from raw materials.
• Commercial and Residential (12% of 2014 greenhouse gas emissions) - Greenhouse gas emissions from businesses and homes arise primarily from fossil fuels burned for heat, the use of certain products that contain greenhouse gases, and the handling of waste.
• Agriculture (9% of 2014 greenhouse gas emissions) - Greenhouse gas emissions from agriculture come from livestock such as cows, agricultural soils, and rice production
• Land Use and Forestry (offset of 11% of 2014 greenhouse gas emissions) - Land areas can act as a sink (absorbing CO2 from the atmosphere) or a source of greenhouse gas emissions. In the United States, since 1990, managed forests and other lands have absorbed more CO2 from the atmosphere than they emit.
Health effects of PM 2.5/PM10
Particles under 10 micrometers in diameter can pass through the nose and throat to enter the lungs, with the smallest ones-PM2.5 and even smaller size fractions-penetrating most deeply and even entering the especially PM2.5 exposures to sever health impacts, including premature death (particularly in those with heart or lung disease), cardiovascular disease such as heart attacks and irregular heart beat, respiratory diseases, and lung cancer. It is important to note that PM is different from air pollutants in that it is defined only by physical characteristics – its size. Other pollutants are defined by their chemistry (as reflected in their molecular notation, such as SO2). But PM2.5 or PM10 can have any chemical composition at all, as long as it takes solid and/or liquid form, is suspended in the air, and meets the given size threshold. This fact hints at how far scientific understanding still has to go in understanding PM2.5 formations, its health effects, and the difficulty of its control.
Health effects of NOx
Exposure to gaseous NO2 irritates the respiratory system and can increase or induce asthma symptoms, but like SO2 the total health impacts of NOx are likely dominated by its roles as precursor to other, secondary air pollutants. These importantly include another type of PM2.5, nitrates, as well as ground-level ozone. Also like SO2, NOx is a source of the acidic compounds that cause acid rain through secondary chemistry.
Health effects of SO2
Exposure SO2 has been shown to cause respiratory illnesses aggravation of cardiovascular and respiratory disease in people who already have it. The largest overall health risk of SO2, however, is almost certainly as a precursor gas that reacts with other gases to form sulfate particles, a major form of the secondary PM2.5.
Health effects of Ground level ozone
Exposure of Ozone cause a variety of adverse effects in the respiratory system, particularly in children, the elderly, and people with lung disease, and an association with [premature death has now been shown. Ozone also diminishes the productivity of many vegetation types during the growing season…..
Health effects of carbon monoxide
When inhaled CO is absorbed by hemoglobin in the blood, limiting oxygen delivery to the organs and tissues of the body, and can cause shortness of breath, dizziness, and at extremely high levels, death. Ambient levels of CO are rarely high enough to cause adverse health effects, except in particular circumstances such as confined areas where combustion is taking place.
Health effects of Lead
Lead is a heavy metal that, when inhaled or otherwise ingested, becomes distributed throughout the body by the bloodstream. It can affect many critical bodily systems including the nervous system, and is especially associated with severe neurological effects in children.
Health effects of VOC
The VOCs can contribute to ozone. And they are also a precursor to one of the largest categories of secondary PM2.5, called secondary organic aerosols. And it their primary, gaseous form, VOCs can cause diverse health effects, though this occurs especially through exposure to high concentrations in confined spaces, particularly indoors.
Official monitored data: Emissions have resulted in high level of pollution measured by the government in the major cities of China. Most policy-oriented analysis of China’s air pollution rely on data from the government’s extensive network of urban monitoring stations, chiefly operated by municipal Environmental Protection Bureaus (EPBs) with data compiled and reported by the Chinese National Environmental Monitoring Center. Such data are collected, analyzed, and reported chiefly for regulatory purposes, as indicators of the progress of pollution control efforts, for guiding air pollution management, and for public communication. (Clear skies over China, 1.4.3, page 19) In recent years, the concentrations of three pollutants have been monitored and reported as daily averages on websites, and as annual averages in published sources: SO2, particulate matter (TSP until 2000, switching to PM10 thereafter), nitrogen oxides (NOx until 1999, NO2 thereafter). Ozone and carbon monoxide (CO) were added to China’s national urban air measurement standards, in 20011, and PM2.5 was added for major cities and key regions in 2012. (Clear skies over China, 1.4.3, page 21) Official monitoring data are almost always reported in aggregated terms, both temporally (such as daily means) and spatially (such as the average of all stations in a city). The nature of the instrumentation and the methods of measurement are rarely specified, limiting the interpretation. (Clear skies over China, 1.5.2, page 28-29) Independent scientific observations: There are three main sources of independent scientific observations of air pollution or GHG levels in China. They are by instruments that are deployed 1. at the surface, at permanent stations or in short-term field campaigns; 2. In the air, on aircraft or balloons; 3. In space, onboard satellites. (Clear skies over China, 1.5.2, page 29)
GHGs
Gases that trap heat in the atmosphere are called greenhouse gases. This section provides information on emissions and removals of the main greenhouse gases to and from the atmosphere. • Carbon dioxide (CO2) : Carbon dioxide enters the atmosphere through burning fossil fuels (coal, natural gas and oil), solid waste, trees and wood products, and also as a result of certain chemical reactions (e.g., manufacture of cement). Carbon dioxide is removed from the atmosphere (or "sequestered") when it is absorbed by plants as part of the biological carbon cycle. • Methane (CH4) : Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from livestock and other agricultural practices and by the decay of organic waste in municipal solid waste landfills. • Nitrous oxide (N2O) : Nitrous oxide is emitted during agricultural and industrial activities, as well as during combustion of fossil fuels and solid waste. • Fluorinated gases : Hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride, and nitrogen trifluoride are synthetic, powerful greenhouse gases that are emitted from a variety of industrial processes. Fluorinated gases are sometimes used as substitutes for stratospheric ozone-depleting substances (e.g., chlorofluorocarbons, hydrochlorofluorocarbons, and halons). These gases are typically emitted in smaller quantities, but because they are potent greenhouse gases, they are sometimes referred to as High Global Warming Potential gases ("High GWP gases"). The primary sources of greenhouse gas emissions in the United States are: • Electricity production (30% of 2014 greenhouse gas emissions) - Electricity production generates the largest share of greenhouse gas emissions. Approximately 67% of our electricity comes from burning fossil fuels, mostly coal and natural gas.[2] • Transportation (26% of 2014 greenhouse gas emissions) - Greenhouse gas emissions from transportation primarily come from burning fossil fuel for our cars, trucks, ships, trains, and planes. Over 90% of the fuel used for transportation is petroleum based, which includes gasoline and diesel.[3] • Industry (21% of 2014 greenhouse gas emissions) - Greenhouse gas emissions from industry primarily come from burning fossil fuels for energy as well as greenhouse gas emissions from certain chemical reactions necessary to produce goods from raw materials. • Commercial and Residential (12% of 2014 greenhouse gas emissions) - Greenhouse gas emissions from businesses and homes arise primarily from fossil fuels burned for heat, the use of certain products that contain greenhouse gases, and the handling of waste. • Agriculture (9% of 2014 greenhouse gas emissions) - Greenhouse gas emissions from agriculture come from livestock such as cows, agricultural soils, and rice production • Land Use and Forestry (offset of 11% of 2014 greenhouse gas emissions) - Land areas can act as a sink (absorbing CO2 from the atmosphere) or a source of greenhouse gas emissions. In the United States, since 1990, managed forests and other lands have absorbed more CO2 from the atmosphere than they emit.
Health effects of PM 2.5/PM10
Particles under 10 micrometers in diameter can pass through the nose and throat to enter the lungs, with the smallest ones-PM2.5 and even smaller size fractions-penetrating most deeply and even entering the especially PM2.5 exposures to sever health impacts, including premature death (particularly in those with heart or lung disease), cardiovascular disease such as heart attacks and irregular heart beat, respiratory diseases, and lung cancer. It is important to note that PM is different from air pollutants in that it is defined only by physical characteristics – its size. Other pollutants are defined by their chemistry (as reflected in their molecular notation, such as SO2). But PM2.5 or PM10 can have any chemical composition at all, as long as it takes solid and/or liquid form, is suspended in the air, and meets the given size threshold. This fact hints at how far scientific understanding still has to go in understanding PM2.5 formations, its health effects, and the difficulty of its control.
Health effects of SO2
Exposure SO2 has been shown to cause respiratory illnesses aggravation of cardiovascular and respiratory disease in people who already have it. The largest overall health risk of SO2, however, is almost certainly as a precursor gas that reacts with other gases to form sulfate particles, a major form of the secondary PM2.5.
Health effects of NOx
Exposure to gaseous NO2 irritates the respiratory system and can increase or induce asthma symptoms, but like SO2 the total health impacts of NOx are likely dominated by its roles as precursor to other, secondary air pollutants. These importantly include another type of PM2.5, nitrates, as well as ground-level ozone. Also like SO2, NOx is a source of the acidic compounds that cause acid rain through secondary chemistry.
Health effects of Ground level ozone
Exposure of Ozone cause a variety of adverse effects in the respiratory system, particularly in children, the elderly, and people with lung disease, and an association with [premature death has now been shown. Ozone also diminishes the productivity of many vegetation types during the growing season…..
Health effects of carbon monoxide
When inhaled CO is absorbed by hemoglobin in the blood, limiting oxygen delivery to the organs and tissues of the body, and can cause shortness of breath, dizziness, and at extremely high levels, death. Ambient levels of CO are rarely high enough to cause adverse health effects, except in particular circumstances such as confined areas where combustion is taking place.
Health effects of Lead
Lead is a heavy metal that, when inhaled or otherwise ingested, becomes distributed throughout the body by the bloodstream. It can affect many critical bodily systems including the nervous system, and is especially associated with severe neurological effects in children.
Ammonia
Ammonia is another important precursor to PM2.5 in China, which reacts with SO2 or NOx to produce ammonium sulfate or ammonium nitrate fine particles. Ammonia is rarely even recognized as an air pollutant, perhaps because its leading sources are agricultural-livestock farming and fertilizer use-and therefore unlike the industrial and/or combustion processes that most associate with air pollution.
Health effects of PM 2.5/PM10
Particles under 10 micrometers in diameter can pass through the nose and throat to enter the lungs, with the smallest ones-PM2.5 and even smaller size fractions-penetrating most deeply and even entering the especially PM2.5 exposures to sever health impacts, including premature death (particularly in those with heart or lung disease), cardiovascular disease such as heart attacks and irregular heart beat, respiratory diseases, and lung cancer. It is important to note that PM is different from air pollutants in that it is defined only by physical characteristics – its size. Other pollutants are defined by their chemistry (as reflected in their molecular notation, such as SO2). But PM2.5 or PM10 can have any chemical composition at all, as long as it takes solid and/or liquid form, is suspended in the air, and meets the given size threshold. This fact hints at how far scientific understanding still has to go in understanding PM2.5 formations, its health effects, and the difficulty of its control.
Health effects of NOx
Exposure to gaseous NO2 irritates the respiratory system and can increase or induce asthma symptoms, but like SO2 the total health impacts of NOx are likely dominated by its roles as precursor to other, secondary air pollutants. These importantly include another type of PM2.5, nitrates, as well as ground-level ozone. Also like SO2, NOx is a source of the acidic compounds that cause acid rain through secondary chemistry.
Health effects of SO2
Exposure SO2 has been shown to cause respiratory illnesses aggravation of cardiovascular and respiratory disease in people who already have it. The largest overall health risk of SO2, however, is almost certainly as a precursor gas that reacts with other gases to form sulfate particles, a major form of the secondary PM2.5.
Health effects of Ground level ozone
Exposure of Ozone cause a variety of adverse effects in the respiratory system, particularly in children, the elderly, and people with lung disease, and an association with [premature death has now been shown. Ozone also diminishes the productivity of many vegetation types during the growing season…..
Health effects of carbon monoxide
When inhaled CO is absorbed by hemoglobin in the blood, limiting oxygen delivery to the organs and tissues of the body, and can cause shortness of breath, dizziness, and at extremely high levels, death. Ambient levels of CO are rarely high enough to cause adverse health effects, except in particular circumstances such as confined areas where combustion is taking place.
Health effects of Lead
Lead is a heavy metal that, when inhaled or otherwise ingested, becomes distributed throughout the body by the bloodstream. It can affect many critical bodily systems including the nervous system, and is especially associated with severe neurological effects in children.
Health effects of VOC
The VOCs can contribute to ozone. And they are also a precursor to one of the largest categories of secondary PM2.5, called secondary organic aerosols. And it their primary, gaseous form, VOCs can cause diverse health effects, though this occurs especially through exposure to high concentrations in confined spaces, particularly indoors.
GHGs
Gases that trap heat in the atmosphere are called greenhouse gases. This section provides information on emissions and removals of the main greenhouse gases to and from the atmosphere.
• Carbon dioxide (CO2) : Carbon dioxide enters the atmosphere through burning fossil fuels (coal, natural gas and oil), solid waste, trees and wood products, and also as a result of certain chemical reactions (e.g., manufacture of cement). Carbon dioxide is removed from the atmosphere (or "sequestered") when it is absorbed by plants as part of the biological carbon cycle.
• Methane (CH4) : Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from livestock and other agricultural practices and by the decay of organic waste in municipal solid waste landfills.
• Nitrous oxide (N2O) : Nitrous oxide is emitted during agricultural and industrial activities, as well as during combustion of fossil fuels and solid waste.
• Fluorinated gases : Hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride, and nitrogen trifluoride are synthetic, powerful greenhouse gases that are emitted from a variety of industrial processes. Fluorinated gases are sometimes used as substitutes for stratospheric ozone-depleting substances (e.g., chlorofluorocarbons, hydrochlorofluorocarbons, and halons). These gases are typically emitted in smaller quantities, but because they are potent greenhouse gases, they are sometimes referred to as High Global Warming Potential gases ("High GWP gases").
The primary sources of greenhouse gas emissions in the United States are:
• Electricity production (30% of 2014 greenhouse gas emissions) - Electricity production generates the largest share of greenhouse gas emissions. Approximately 67% of our electricity comes from burning fossil fuels, mostly coal and natural gas.[2]
• Transportation (26% of 2014 greenhouse gas emissions) - Greenhouse gas emissions from transportation primarily come from burning fossil fuel for our cars, trucks, ships, trains, and planes. Over 90% of the fuel used for transportation is petroleum based, which includes gasoline and diesel.[3]
• Industry (21% of 2014 greenhouse gas emissions) - Greenhouse gas emissions from industry primarily come from burning fossil fuels for energy as well as greenhouse gas emissions from certain chemical reactions necessary to produce goods from raw materials.
• Commercial and Residential (12% of 2014 greenhouse gas emissions) - Greenhouse gas emissions from businesses and homes arise primarily from fossil fuels burned for heat, the use of certain products that contain greenhouse gases, and the handling of waste.
• Agriculture (9% of 2014 greenhouse gas emissions) - Greenhouse gas emissions from agriculture come from livestock such as cows, agricultural soils, and rice production
• Land Use and Forestry (offset of 11% of 2014 greenhouse gas emissions) - Land areas can act as a sink (absorbing CO2 from the atmosphere) or a source of greenhouse gas emissions. In the United States, since 1990, managed forests and other lands have absorbed more CO2 from the atmosphere than they emit.
Health effects of PM 2.5/PM10
Particles under 10 micrometers in diameter can pass through the nose and throat to enter the lungs, with the smallest ones-PM2.5 and even smaller size fractions-penetrating most deeply and even entering the especially PM2.5 exposures to sever health impacts, including premature death (particularly in those with heart or lung disease), cardiovascular disease such as heart attacks and irregular heart beat, respiratory diseases, and lung cancer. It is important to note that PM is different from air pollutants in that it is defined only by physical characteristics – its size. Other pollutants are defined by their chemistry (as reflected in their molecular notation, such as SO2). But PM2.5 or PM10 can have any chemical composition at all, as long as it takes solid and/or liquid form, is suspended in the air, and meets the given size threshold. This fact hints at how far scientific understanding still has to go in understanding PM2.5 formations, its health effects, and the difficulty of its control.

Ammonia

Ammonia is another important precursor to PM2.5 in China, which reacts with SO2 or NOx to produce ammonium sulfate or ammonium nitrate fine particles. Ammonia is rarely even recognized as an air pollutant, perhaps because its leading sources are agricultural-livestock farming and fertilizer use-and therefore unlike the industrial and/or combustion processes that most associate with air pollution.

Topology and climate factors affecting air quality

In addition to the level of emissions, air quality will be affected by topology and climate factors that affect whether pollutants build up in the atmosphere or are dispersed. The Beijing-Tianjin-Hebei region is a good example of this problem, having a topology and climate patterns that exacerbate the pollution problem. The region is bounded by mountains to the north, which means that when winds are from the south, pollution is trapped. Northwesterly winds can be effective in dispersing pollution rapidly, bringing clear air in their wake. But wind speeds have dropped in recent years, making the problem worse. The region is also affected by temperature inversions, or flows of warm air that can prevent normal convection and trap polluted air close to the ground This combination of factors means that emission levels that might be tolerable in another area generate build ups of pollution that quickly exceed safe levels.

Environmental carrying capacity

The idea of carrying capacity originated in biology, and was used to determine the number of a species that could survive indefinitely in a given environment. It has since been widely used in attempts to determine the maximum sustainable population that the earth can support. However, estimating carrying capacity is much more difficult, and controversial, for humans than for other species, because their production and consumption activities vary widely. They determine the level of use of resources and can also degrade or destroy them. Technology can also affect the human-resources relationship in both positive and negative ways, as can trade. The concept of environmental carrying capacity has been used in the context of regional development and pollution control by researchers trying to assess how regional capacity to sustain human populations of different sizes and tolerate different levels of pollution. While usually applied to natural resources or “eco-systems” services, the idea of carrying capacity can also be extended to the social environment. http://www.sustainable-environment.org.uk/Principles/Carrying_Capacity.php For a discussion of the current situation regarding the analysis of environmental carrying capacity in China, see http://english.caixin.com/2015-01-14/100774146.html Estimating carrying capacity for air, water and soil pollution has different challenges Estimating regional levels of carrying capacity for air pollution is difficult because they are affected not only by levels of emissions but also by topological considerations and climate factors, including wind speed and direction, and temperature inversions that affect the extent to which pollution is dispersed. This report contains a discussion of air pollution and carrying capacity in China’s major cities. http://environmental-partnership.org/wp-content/uploads/2015/09/China_Air_Quality_Management_Assessment_Report.pdf

Temperature inversions

Usually, the warmer air and emissions generated by activities close to the ground in cities will naturally flow upward into the cooler upper levels of the atmosphere and be dispersed through convection. When an inversion occurs, a narrow belt of warmer air forms at an intermediate level, interrupting the usual gradation from warm to cold and forming a cap which traps the air below. This can cause a build-up of smog. Inversions are caused by climate patterns but are also affected by topology (the lie of the land) and they are more common in cities in mountain basins or on plains with mountains behind. This applies to Beijing and other cities in the JJJ region. Temperature inversions are often part of the explanation for extreme pollution events, for example the London smog of 1952, and many of severe pollution episodes in Beijing. The important point to note is that in cities that are prone to inversions, emissions can quickly build to form more dangerous levels of pollution than they otherwise would. Policy therefore needs to take account of this.

Technical standards: cement

Since the 11th Five Year Plan new technical requirements have been introduced for the cement industry. Newly built clinker production installations must install NOX-removal equipment to treat emissions with no less than a 60% removal rate, as well as installing online real-time monitoring system and other highly effective pollution treatment equipment). These standards have applied to newly constructed cement plants since 1 March 2014 and to existing plants since 1 July 2015

Emissions standards: cement industry

In 2013, the Ministry of Environmental Protection, introduced new standards for emissions in the cement sector.
 Emission Standard of Air Pollutants for the Cement Industry (GB 4915-2013),  Standard For Pollution Control On Co-Processing Of Solid Wastes In Cement Kiln (GB 30485-2013) and the, supplementary Environmental Protection Technical Specification For Co-Processing Of Solid Wastes In Cement Kiln (HJ 662-2013). The new standards set the PM emission limit at 30 mg/m3 (for thermal equipment such as cement kilns) and 20 mg/m3 (for ventilation equipment such as cement grinding mill), in comparison to 50 mg/m3 and 30 mg/m3 respectively previously (MEP, 2014). The NOX emission limit is set at 400 mg/m3 in comparison to the current 800 mg/m3, in order to urge the cement producers to employ both process control (e.g., low NOX burner, graded combustion in decomposing furnace, fuel replacement) and end-of-pipe control of NOX emissions. The new standards also set tougher requirements for control of odor and heavy metal pollution. Regional emissions limits In accordance with No. 14 Announcement of MEP in 2013, special air pollution emission limits apply for companies based in three regions and ten city clusters, while local governments may extend the scope and set tougher requirements for enforcing the special emission limits.

Emissions standards: cement industry

In 2013, the Ministry of Environmental Protection, introduced new standards for emissions in the cement sector.
 Emission Standard of Air Pollutants for the Cement Industry (GB 4915-2013),  Standard For Pollution Control On Co-Processing Of Solid Wastes In Cement Kiln (GB 30485-2013) and the, supplementary Environmental Protection Technical Specification For Co-Processing Of Solid Wastes In Cement Kiln (HJ 662-2013). The new standards set the PM emission limit at 30 mg/m3 (for thermal equipment such as cement kilns) and 20 mg/m3 (for ventilation equipment such as cement grinding mill), in comparison to 50 mg/m3 and 30 mg/m3 respectively previously (MEP, 2014). The NOX emission limit is set at 400 mg/m3 in comparison to the current 800 mg/m3, in order to urge the cement producers to employ both process control (e.g., low NOX burner, graded combustion in decomposing furnace, fuel replacement) and end-of-pipe control of NOX emissions. The new standards also set tougher requirements for control of odor and heavy metal pollution.
Regional emissions limits In accordance with No. 14 Announcement of MEP in 2013, special air pollution emission limits apply for companies based in three regions and ten city clusters, while local governments may extend the scope and set tougher requirements for enforcing the special emission limits.

Cement Industry

China produced 58% of the world’s cement in 2013, making it the world’s largest market. As the primary material used to make concrete for buildings and roads, cement use has increased in tandem with China’s economic growth, housing construction and highway development. The industry is the largest contributor to pm 2.5 (15-20%) of PM2.5 emissions and the second biggest contributor to SO2 (3.4%). It also contributes 8-10% of NO2 emissions, as well as greenhouse gases and mercury.

Cement: policy

As a major contributor to pollution, the cement industry has been a target of policy for some time. Policies have pursued a number approaches under successive Five Year Plans: •More stringent emissions standards for the cement industry
•Technical requirements for the industry, including energy efficient boilers and more efficient, cleaner kilns
•Less environmentally damaging raw materials
•Phasing out of overcapacity
Sanctions agains non-compliant firms included withholding of credit and land permits, and even cutting electricity supplies.
Policy effectiveness
Under China’s 11th Five-Year Plan (2006-2010), there was a 19.1% fall in energy intensity per unit of GDP (Yuan et al, 2011). In the cement industry, the amount of energy required to produce a metric ton of cement fell by 41% (QEACBM, 2011) The MEP estimates that after new emissions standards are enforced, PM emissions from the cement industry will be cut around 770,000 t(30.8%-38.5%) from the baseline of 2-2.5 million metric tons; the NOX emission will be cut about 980,000 t (44.5%-51.6%) from the baseline of 1.9-2.2 million metric tons, effectively controlling the pollution load of HCl, HF, heavy metals, and dioxins, and meanwhile contributing to the reduction of GHG emissions (MEP China, 2014). However, problems remain in terms of energy efficiency and environmental impact. Coal is still the primary fuel and energy consumption even in new kilns is 15-25% higher than the international average. Policy challenges and tradeoffs