What are the seven major primary air pollutants and their sources?

Primary air pollutants are those that are emitted directly from sources. They are harmful and can cause health issues and environmental damage. Examples include carbon monoxide from car exhausts, and sulfur dioxide from factories.

The seven major primary air pollutants are Carbon Monoxide (CO), Sulfur Dioxide (SO2), Nitrogen Dioxide (NO2), Nitrogen Oxide (NO), Particulates, Volatile Organic Compounds (VOC), and Lead.

Sources of these pollutants are as follows: Carbon Monoxide (CO) primarily comes from vehicle exhaust and incomplete combustion. Sulfur Dioxide (SO2) has sources in fossil fuel combustion, especially in power plants. Nitrogen Dioxide (NO2) and Nitrogen Oxide (NO), collectively referred to as NOx, are emitted from high-temperature combustion like car engines and power plants. Volatile Organic Compounds (VOC) have diverse sources, including paints, cleaning supplies, and vehicle exhaust. Particulates are emitted by many operations involving combustion such as motor vehicles, power generation, and residential wood burning. And, finally, Lead historically came from motor vehicles but now it's predominantly from industrial processes like battery manufacturing and smelters.