What does "PM" stand for in the context of air quality?

In the context of air quality, "PM" stands for Particulate Matter. This term refers to microscopic solid or liquid matter suspended in the Earth's atmosphere, which can include dust, dirt, soot, and smoke. Particulate Matter is typically classified into two categories based on size: PM10, which includes particles with a diameter of 10 micrometers or smaller, and PM2.5, which refers to particles with a diameter of 2.5 micrometers or smaller. These particles pose significant health risks as they can be inhaled and cause respiratory issues, cardiovascular problems, and other health complications. Monitoring and controlling levels of Particulate Matter is crucial for maintaining air quality and protecting public health.