Mobile sources of air pollution:

• Mobile source air pollution includes any air pollution emitted by motor vehicles, airplanes, locomotives, and other engines and equipment that can be moved from one location to another.
• Many of these pollutants contribute to environmental degradation and have negative effects on human health.
• Due to the large number of mobile sources of air pollution, and their ability to move from one location to another, mobile sources are regulated differently from stationary sources, such as power plants.
• Mobile source air pollutants are carbon monoxide, carbon dioxide, nitrous oxides, hydrocarbons, particulate matter, air toxics etc.

Stationary sources of air pollution:

• A stationary source in air quality terminology is any fixed emitter of air pollutants, such as fossil fuel burning power plants, petroleum refineries, petrochemical plants, food processing plants and other heavy industrial sources.
• The primary origin of local air pollution has been emissions from stationary sources. These sites include power generating plants, oil refineries, chemical plants, steel factories, cement and glass manufacturing companies, space heating, and many other industries.
• Pollutants are emitted into the air from these plants through fossil fuel combustion, chemical processes, and the grinding or pulverizing of metals for cement, fertilizers, etc.
• These processes emit a number of harmful contaminants into the air. The most damaging being sulfur dioxide, nitrogen oxides, carbon dioxide, synthetic compounds, and particulate matter.