Sulfur dioxide can cause nose and throat irritation and lung problems such as bronchitis. Nitrogen Oxides react with organic compounds to form smog, and are also major components of acid rain. U.S. health standards for air quality are based on the concentration of particles small enough to be inhaled deep into the lungs. These are particles with a diameter of less than 10 microns. Particulates are produced by many sources, including burning of diesel fuels, incineration of garbage, mixing and application of fertilizers and pesticides, road construction, industrial processes such as steelmaking, mining operations, agricultural burning and the operation of fireplaces and woodstoves.
Particulate pollution can cause eye, nose and throat irritation and other health problems.
Fine-particle pollution typically contains soot, acid condensates, and sulfate and nitrate particles. This type of pollution is thought to pose greater health risks not only because the particles can be breathed more deeply into the lungs, but also because they are more likely to be toxic than larger particles. This legislation set the stage for federal as opposed to regional air quality standards and statutory deadlines for compliance. Pollutants covered under the act are known as criteria pollutants. The law sets emissions standards for stationary sources such as power plants as well as mobile sources such as automobiles and trucks.