There are two main categories of air pollution. These are primary pollutants and secondary pollutants. Some primary pollutants include suspended particulate matter, volatile organic compounds, carbon monoxide, and nitrogen oxide. The other primary pollutants are sulfur dioxide, lead, air toxics, and radon. There are two secondary pollutants which are ozone and peroxyacetyl nitrates. Secondary pollutants are caused when the primary pollutants continue to go through reactions. The majority of these pollutants are caused by combustion of one thing or another. For example, nitrogen oxide is caused by the high combustion temperatures of burning fuel.
Effects of air pollution on humans
Two of these pollutants affect the cardiovascular system of the human body. These are particulates and carbon monoxide. Radon can build up in homes and is one of the leading causes of cancer. Some major sources of acid rain include nitrogen oxides and sulfur dioxide. In addition there are 187 known toxins and most of them are carcinogens. While these may all have different effects, no specific one is worse than the other. Some of these occur naturally and there is nothing that can be done about them. The others, however, should be dealt with as soon as possible.
Pollutants have three general effects on human health: chronic, acute, and carcinogenic. The main chronic effects are chronic obstructive pulmonary disease (COPD), asthma, and lead poisoning. The acute effects usually only take place when the person has an underlying condition. It normally must be in high concentration, and it comes on quick and can be lethal. One example of an acute effect without underlying causes would be carbon monoxide poisoning. If a pollutant has a carcinogenic effect, then it can cause cancer. The number one source of this effect is diesel exhaust.
Environmental impacts of Air Pollution
Environmental impacts can be more severe than human impacts and are usually caused by ozone. When the ozone levels get high enough they destroy crops and cause countries to lose several billion dollars per year in lost crops. The impact on forests is substantially worse than on crops. Studies have shown that the ozone from Central Valley and San Francisco initially caused the damage to the ponderosa and pines along the Sierra Nevada. The ozone weakened the trees so that it could become overcome by western pine beetles. Forests that have been affected by ozone have a much higher risk of being attacked by insects and other dangers. Exposed surfaces, paints and fabrics, and metals are also affected negatively by pollution. Exposed surfaces become dingy due to particulates. Paints and fabrics deteriorate; and metals are corroded causing people to spend hundreds of millions more dollars to repair them each year. One other effect on the environment is that pollution reduces visibility, which can have a psychological effect on people.
Tracking and controlling air pollution
The Environmental Protection Agency, EPA, has a section called the Clearinghouse for Inventories and Emissions Factors. They are responsible for tracking trends in the emissions of all of the primary pollutants. In 2008, carbon monoxide ranked high with 80 million metric tons. Organic compounds followed behind that with a national emission of 16.7 metric tons. Next in line came nitrogen oxides, sulfur dioxide, and particulate matter with 15.4 million, 11.7 million, and 4.9 million metric tons, respectively. Transportation was a major source for three of these pollutants followed by electric utilities, dust, tires, etc.
The first air pollution control measure was enacted by Congress in 1970. The measure, called the Clean Air Act of 1970 (CAA), is carried out by the EPA and contains two amendments from 1977 and 1990. This acts identifies wide spread pollution, sets standards, and establishes control methods. Under the CAA the National Ambient Air Quality Standards (NAAQS) and the National Emission Standards for Hazardous Air Pollutants (NESHAPs) were established. The first is responsible for setting primary standards for the criteria pollutants while the second tracks and regulates these pollutants.
One control strategy called the command and control regulates emissions so that the ambient criteria pollutants stay below the primary standard levels. Another way to reduce pollution is to put a catalytic converter on all cars which converts the dangerous emissions to nitrogen gas and carbon dioxide. Also, the EPA has required industries to use cleaner burning fuels and has set emission standards for stationary-source categories such as paper mills. The CAA has required all facilities built after 1970 to use the best pollution control technology when building and operating. An example of these pollution control technologies is modern scrubbers. The CAA allowed that all older buildings need not comply with this policy unless they were to upgrade their facilities.
Wright, R. & Boorse D. (2005). Environmental science: Toward a sustainable future. San Fransisco, CA: Pearson Education Inc.