The second type is sulfur oxides which come from the burning of coal and industrial processes. Damage to materials, to vegetation, and to the human respiratory system are caused by the acid nature of oxides. The third type of pollutant is carbon monoxide. Carbon monoxide is a colorless, odorless, tasteless gas against which humans have no protection. Hemoglobin, which is in the blood, combines with carbon monoxide and carries less oxygen to body tissues causing health and heart effects.
Some health problems come from the exhaust fumes leaking into the interior of the automobile.
Several hundred Americans die from CO poisoning each year. Sodium oxide levels below .25 ppm have been associated with increased morbidity in New York as measured by hospital admissions. The fourth type is hydrocarbons which are chemical compounds containing only carbon and hydrogen. Hydrocarbons also arise from gasoline-powered vehicles and from industrial processes. The last type is nitrogen oxides that come from high-temperature combustion, such as that occurring in motor vehicle engines, electric power plants and other fuel usage.