What is particulate matter air pollution?
Particulate matter (PM), or particle pollution, refers to very small particles in the air that we breathe. Particulate matter air pollution can cause a variety of health problems. Particle pollution is made up of different substances, including carbon, sulphur and nitrogen compounds metals, and soil or dust particles. These particles come in different shapes and sizes and can be either solid or liquid particles. Particle size is usually measured in units of one millionth of a metre – a micron. PM10 refers to particles that are 10 micrometers or smaller in diameter. This is about one-eighth the diameter of a human hair. PM10 includes coarse particles that range in size from 2.5-10 micrometers in diameter. Fine particles, which have diameters less than 2.5 micrometers (PM2.5) are most closely linked to serious health effects. Fine particles can be inhaled more deeply into the lungs, where they are slow to clear.
