PM stands for Particulate Matter and the number for the size. The particle size is measured in µm.
Particulate Matter is almost invisible. Particulate Matter comes in both large and fine sizes.
The particles are divided into three classes:
- Particles with a diameter of 10 micrometers, i.e. ten millionths of a meter or less (PM10).
- Particles that are four times smaller, i.e. PM2.5 with a diameter of less than 2.5 micrometers.
- Particles that are one micrometer and smaller: so-called ultra-fine dust PM1.
Most data are available for PM2.5 and PM10
You can measure PM2.5 and PM10 yourself with our airRohr Sensor Kit
Sources of air pollution
Human activity is a major cause of air pollution, much of which results from industrial processes, fossil fuels burning, agriculture and landfills. Naturally causes can be such as wildfires, dust storms, animal digestion and volcanic eruptions.
- Particulate matter: Road dust, Wear and tear of brakes and tires on vehicles, construction activities, forest fires, pollen, etc.
- Carbon monoxide: Incomplete combustion of any fuel like natural gas or coal.
- Ozone: Created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOCs). Emissions from industrial facilities, motor vehicle exhaust and chemical solvents are some of the major sources of NOx and VOCs.
- Nitrogen dioxide: Combustion of fossil fuels.
- Sulphur dioxide: Combustion of fossil fuels.