Gaseous Air pollutants

Carbon monoxide is both odorless and colorless and it's produced through combustion. Most carbon monoxide emissions come from vehicles, about 62%, but they also come from forest fires, lawn equipment and the burning of industrial waste. This pollutant is dangerous to human health because, even in very small concentrations, it can prevent oxygen from being delivered through your body to major organs. At higher levels, it can cause death.

Sulfur dioxide is also a colorless gas, and it's highly reactive. About 70% of sulfur dioxide emissions come from combustion at industrial power plants, like those that generate electricity from coal. Sulfur in the coal reacts with atmospheric oxygen in the air and forms the compound sulfur dioxide. Once in the air it may react further to create sulfur acid, which can fall back to Earth as acid rain. Sulfur dioxide can also cause respiratory illnesses when it's breathed in.

Solid air pollutants

Particulates:

Atmospheric particulate matter – also known as particulate matter (PM) or particulates – is microscopic solid or liquid matter suspended in the Earth's atmosphere. The term aerosol commonly refers to the particulate/air mixture, as opposed to the particulate matter alone.[3] Sources of particulate matter can be man-made or natural. They have impacts on climate and precipitation that adversely affect human health. Subtypes of atmospheric particle matter include suspended particulate matter (SPM), respirable suspended