Made to measure: hook-and-loop or roll
What is particulate matter (PM)?
Particulate matter is the general name for small solid and liquid particles suspended in the air. Dust, pollen, soot, smoke, sea salt and industrial particles all belong to this group. In air quality measurements, these particles are classified by size.
The difference between PM10 and PM2.5
- PM10: Particles 10 micrometres in diameter or smaller. Much of the road dust, construction dust, soil and pollen falls into this group.
- PM2.5: Finer particles 2.5 micrometres in diameter or smaller. Most particles from exhaust, chimney smoke, industry and combustion fall into this group.
To give you an idea: a human hair is tens of micrometres thick. PM2.5 particles cannot be seen one by one; only when they are concentrated do they show up as haze in the air.
Why does it matter?
The smaller the particles, the deeper they can reach into the airways. That is why health authorities draw particular attention to fine particles, and PM2.5 and PM10 values are prominent in air quality indexes.
