Particulate Matter (PM) refers to a complex mixture of extremely small particles and liquid droplets suspended in the air. These particles come in various sizes and can be made up of a variety of substances including organic chemicals, metals, soil, and dust particles. Particulate matter is generally categorized into two types: PM10 (particles with diameters of 10 micrometers or less) and PM2.5 (particles with diameters of 2.5 micrometers or less).
