While agriculture can contribute to air pollution through activities such as livestock farming and the use of fertilizers, it is not typically considered a major source of air pollution in urban areas.

Volatile organic compounds (VOCs) react with nitrogen oxides in the presence of sunlight to form smog, which is characterized by a hazy brown or orange color.

Motor vehicles, particularly diesel-powered vehicles, are a major source of nitrogen oxides (NOx) emissions due to the high temperatures and pressures in their engines.

Coal-fired power plants are the primary source of sulfur dioxide (SO2) emissions in the United States due to the high sulfur content of coal.

Sulfur dioxide (SO2) is a major contributor to acid rain, as it reacts with water vapor in the atmosphere to form sulfuric acid.

Emission control refers to the technologies and strategies used to reduce the release of pollutants from vehicles, such as catalytic converters and particulate filters.

Nitrogen oxides (NOx) are not greenhouse gases, although they can contribute to the formation of ground-level ozone, which is a greenhouse gas.

Air purification refers to the process of removing pollutants from the air, typically through the use of filters, scrubbers, or other technologies.

While forest fires can contribute to particulate matter (PM) emissions, they are not typically considered a major source of PM emissions in urban areas.

Industrial emission control refers to the technologies and strategies used to reduce the release of pollutants from industrial sources, such as scrubbers, filters, and process modifications.

While transportation can contribute to air pollution in rural areas, it is not typically considered a major source of air pollution in rural areas compared to agricultural and industrial activities.

Residential emission control refers to the technologies and strategies used to reduce the release of pollutants from residential sources, such as cleaner heating systems and improved insulation.

While deforestation can contribute to air pollution through the release of greenhouse gases, it is not typically considered a major source of air pollution in developing countries compared to industrial activities, motor vehicles, and residential cooking.

Agricultural emission control refers to the technologies and strategies used to reduce the release of pollutants from agricultural sources, such as improved manure management and reduced fertilizer use.

While residential heating can contribute to air pollution in coastal areas, it is not typically considered a major source of air pollution in coastal areas compared to industrial activities, motor vehicles, and shipping activities.