User:Vunife/Particulate Pollution

Atmospheric particulate matter
Atmospheric particulate matter, also known as particulate matter, or PM, describes solids and/or liquid particles suspended in a gas, most commonly the Earth's atmosphere. Particles in the atmosphere can be divided into two types, depending on the way they are emitted. Primary particles, such as mineral dust, are emitted into the atmosphere. Secondary particles, such as ammonium nitrate, are formed in the atmosphere through gas-to-particle conversion.