Particulate Matter

Particulate Matter (PM) is made up of a combination of both solids and liquid droplets. PM levels can be high even indoors when the outdoor concentrations are incredibly high. They come in a range of sizes but are broken up into two specific designations: coarse and fine.

Coarse particles are between 2.5 and 10 micrometers and usually the result of the crushing and grinding of ore, pollen and mold spores, and dust/sand blown by the wind.

Fine particles (PM_2.5) are pollutants less than 2.5 micrometers in diameter, small enough to enter our lungs and pass into the bloodstream. These particles are created through combustion processes: such as the burning of fossil fuels, forest fires, energy production, and some industrial activities. Black carbon is a significant component of PM_2.5.

Source: EPA.gov