What is the Difference Between Aerosol and Particulate Matter?

The difference between aerosol and particulate matter lies in their composition and size. Here are the key differences:

Aerosol: An aerosol is a suspension of solid or liquid particles in the air, along with the surrounding gases. It can refer to both particulate matter and the gas phase, depending on the context. When particulate matter is suspended in a gas, it is called an aerosol. Aerosols can come from both natural and anthropogenic sources and can have various health and environmental impacts.
Particulate Matter: Particulate matter, also known as particulate pollution, refers only to the suspended solid or liquid matter in the air. Unlike aerosols, it does not account for the surrounding gases. Particulate matter can be emitted directly from sources such as construction sites, smokestacks, or fires, or it can form in the atmosphere as a result of complex reactions of chemicals emitted from power plants, industries, and automobiles.

Particulate matter comes in various sizes, with fine particles (PM2.5) being less than 2.5 micrometers in diameter and coarse particles (PM10) being between 2.5 and 10 micrometers in diameter. The smaller the particles, the greater their potential to cause health problems, as they can penetrate deeper into the lungs and even enter the bloodstream.

In summary, while both aerosols and particulate matter refer to the suspended particles in the air, aerosols also include the surrounding gases, whereas particulate matter only refers to the suspended particles themselves.