All potential sources of air pollution (mobile, point and area sources) must comply with the provisions of the law. All emissions must be within the air quality standards.
Mobile sources refer to vehicles like cars, trucks, buses, jeepneys, tricycles, motorcycles, and vans.
Point sources refer to stationary sources such as industrial firms and the smokestacks of power plants, hotels, and other establishments.
Area sources refer to sources of emissions other than the above. These include smoking, burning of garbage, and dust from construction, unpaved grounds, etc.
Department of Environment and Natural Resources. (2003, August). Primer on the Clean Air Act. Diliman: DENR-Public Affairs Office.