Introduction
More Than Greenhouse Gases

On a national level, most of the discussion over the last decade about air pollution has centered around mankind's emissions of greenhouse gases. The reason for this is connection between global warming and greenhouse gases. Most of the discussions about other forms of air pollution have been more localized to major cities, where the density of polluting machinery is great enough to have a serious impact. Cities like Houston, Atlanta, Denver, and Los Angeles have air quality that is so bad that the public is warned to limit the amount of time that is spent outdoors on certain days of the year. However, outside of these areas, there is little discussion of what might be released in the air that could cause the air to be toxic.

This was not the case during the 1970's, when air pollution, as well as water pollution, was a national topic. Threats such as acid rain were non-localized, and did not allow rural folks to pay not attention. It was in this societal that a piece of legislation like the Clean Air Act could be passed. This act put strict limits on the amounts and types of pollution that could be emitted from machinery, and led to a general increase in the overall air quality of the nation.

Clean Air Act

The Clean Air Act caused some major changes in the way that machinery operates. One good example of this is the use of catalytic converters in today's automobiles. These devices cause many of the pollutants that are produced in internal combustion engines to undergo further reactions to break them down before they leave the tailpipe. Because of the nature of the catalytic converts, engines and fuels had to undergo a radical shift in the late 1970's. Before this time, lead was added to gasoline as a way of preventing "knocking" that occurred when valves did not seat properly and allowed fuel vapors to leak from the combustion chamber. After combustion in the engine, the lead was put out as a pollutant in the exhaust. However, no acceptable method of removing the lead from the exhaust could be found. In fact, the use of lead caused the catalytic converters that were put on the cars to stop functioning, thus allowing all of the pollutants to be put into the air. Because of this, cars with catalytic converters were prohibited from using leaded gasolines. As more and more cars came onto the market that could not use leaded gasoline, the demand for this gas disappeared in the early 1980's, causing it to disappear from the landscape. The fact that you can still find gasoline station pumps that say "Unleaded" is a testament to the fact that we once used leaded gas.

While the Clean Air Act has done a great job of cleaning up the air, some people have begun to question it, arguing that it is too stringent and hampers industry. This argument has been getting a great boost lately as America looks toward trying to achieve energy independence from foreign countries. One way that some people see us being able to do this is to begin to have a higher reliance on coal, in which the U.S. is richly endowed. Besides the fact that it releases greenhouse gases, one of the problems with coal is that it burns dirty. Bituminous coal, in particular, has a great deal of sulfur, which creates sulfur dioxide when it is burned and leads to increases in acid rain. There are methods for reducing these emissions of sulfur dioxide; however, these methods all require a greater cost to use this coal. Some people would like to reduce the ability of the Clean Air Act to require cleaner burning of coal so that we could increase its use.

The sites below provide data on the types and amounts of air pollutants that are released in the U.S., as well as information on the Clean Air Act and recent attempts to weaken it.

Air Pollution

Data for Emissions of CO, NOx, VOC, Particulates, SO2, and Lead
Air Pollution Trends in Selected Cities (BTS)

Clean Air Act

Clean Air Act (EPA)

Pro-Clean Air Act Organizations

Clean Air Trust
SaveTheCleanAirAct.org

Anti-Clean Air Act Organizations

Edison Electric Institute
Coalition for Affordable and Reliable Energy

After reading through these and any other sites that you might find, answer the following questions

• The Air Pollution Trends website seems to indicate that the air quality of cities in California has gotten better since 1989. The number of AQI days over 100 has decreased in almost every one of the cities there. What do you think is the reason for this decrease in the amount of air pollution in California?
• Many companies would like to replace the stringent requirements of the Clean Air Act with a "cap-and-trade" scheme that would allow air-polluting industries to continue to pollute as long as they could find another company from which they could buy pollution credits. Do you think that this program is going to increase or decrease the air quality in the U.S.? Why or why not?
• Many companies that produce air pollutants tout their environmental records in both advertisements and on their website. Do you believe that these claims are the result of a sincere concern for the environment that would drive the company to clean the air on their own, or are these claims the result of the company being forced to comply with federal and state mandated guidelines? What evidence leads to this conclusion?

Many of us do not know where our local power plant is. Since a great deal of the air pollution in the U.S. is generated by power plants, this is an excellent time to find out just where it is located. The Department of Energy's EIA website can assist you in finding your nearest facility and the type of fuel that it uses. Take a ride out to this facility.