1. 16.4 Control of Air Pollution
In the U.S., implementation of the requirements of the Clean Air Act has been the primary means of controlling air pollution.
Under the Clean Air Act, a variety of pollution control mechanisms have been employed and the quality of air has improved significantly in the last 27 years.
The EPA is responsible for developing and meeting air quality standards.
Industry must meet a series of detailed control requirements with the goal of improving air quality.

2. 16.4 Control of Air Pollution
Motor vehicles are the primary source of several important air pollutants: carbon monoxide, VOCs, and nitrogen oxides.
Catalytic converters reduce these emissions.
Lead-free fuel has reduced the amount of lead in the atmosphere.
Ozone levels depend on VOC and NO2 levels, and have fallen somewhat but still need improvement in some areas of the country, particularly California and the northeast U.S.

3. 16.4 Control of Air Pollution
Mining, farming, transfer of grain or coal, and road dust are sources of particulate emissions.
Forest fires, grass fires, leaf burning, fireplaces, and woodstoves are a significant source of particulate matter.
Some municipalities ban wood burning stoves and fireplaces, while high-efficiency wood stoves significantly reduce particulate emissions.
Burning of fossil fuels is another source of particulate matter.
Diesel engines are a source of particulate matter.

4. 16.4 Control of Air Pollution
Improvement in air quality

5. 16.4 Control of Air Pollution
Power plant emissions
Particulates and sulfur dioxide are associated with electric power plants.
Filters and mechanical means control particulates.
The control of sulfur dioxide requires changes to the way electricity is produced. The EPA has set limits and allow the electric utility to decide which options are best for them.

6. 16.4 Control of Air Pollution
Low-sulfur coal reduces sulfur emissions by 66%.
Switching to oil, natural gas, or nuclear fuels further reduces sulfur emissions.
40% of sulfur can be removed before the fuel is used.
Smokestack gases can be scrubbed before they are emitted.
The technology is available, but costly to install, maintain, and operate.