APES - Pollutants

Primary Air Pollutants

Harmful substances directly released into the air from a source without undergoing chemical transformation.

Carbon Monoxide (CO)

A primary pollutant produced by incomplete combustion of fossil fuels, such as vehicle engines.

Nitrogen Oxides (NOx)

Primary pollutants emitted from vehicles and power plants due to burning fossil fuels.

Sulfur Dioxide (SO₂)

Released from burning coal and oil, and industrial processes like metal smelting.

Particulate Matter (PM)

Tiny particles released from vehicles, factories, and natural sources like wildfires.

Volatile Organic Compounds (VOCs)

Emitted from vehicle exhaust and industrial processes, often from solvents or paints.

Ammonia (NH₃)

A primary pollutant released from agricultural activities like livestock waste and fertilizers.

Lead (Pb)

Historically released from vehicle exhaust due to leaded gasoline, also from industrial activities.

Smog

A mixture of pollutants, including ozone and particulate matter, that results from reactions involving primary pollutants.

Methane (CH₄)

A primary pollutant produced by livestock digestion and rice paddies.

Ground-Level Ozone (O₃)

A secondary pollutant formed when nitrogen oxides and VOCs react in sunlight.

Peroxyacetyl Nitrates (PANs)

Secondary pollutants formed when VOCs react with nitrogen oxides in the atmosphere.

Sulfuric Acid (H₂SO₄)

A secondary pollutant formed from the reaction of sulfur dioxide with oxygen and water vapor.

Nitric Acid (HNO₃)

Created when nitrogen oxides react with water vapor and oxygen, contributing to acid rain.

Fine Particulate Matter (PM2.5)

Can be a secondary pollutant formed from reactions involving gases like sulfur dioxide and nitrogen oxides.

Acid Rain

Precipitation that contains sulfuric and nitric acids, resulting from the transformation of primary pollutants.

Transportation Emissions

Sources of primary pollutants including aircraft, trucks, ships, and rail systems.

Natural Sources of Pollution

Includes wildfires, volcanic eruptions, and dust storms that release primary pollutants into the atmosphere.

Temperature Effect on Pollutants

Higher temperatures can accelerate chemical reactions, leading to the formation of more secondary pollutants.

Decomposition in Landfills

Creates methane, a potent greenhouse gas and primary pollutant, from organic waste.