PM10 and air pollution: what do the values mean?
PM10 means airborne particles no larger than 10 micrometres. They are small enough to be inhaled into the respiratory system, which makes particle concentration an important measure of air quality. PM2.5 is the finer fraction, no larger than 2.5 micrometres.
Where does particle pollution come from?
- Heating: wood and coal burning can be a major winter source.
- Traffic: exhaust, brake and tyre wear and resuspended road dust.
- Industry and agriculture: construction, soil cultivation and harvesting.
- Natural sources: long-range dust, including Saharan dust, can raise readings over a large area.
How to interpret a reading
| PM10 daily average | Indicative level | What to consider |
|---|---|---|
| 0–25 µg/m³ | Low | No special action is normally needed. |
| 26–50 µg/m³ | Moderate | Sensitive people may wish to monitor symptoms. |
| 51–75 µg/m³ | Elevated | Sensitive people should reduce strenuous outdoor activity. |
| 76–100 µg/m³ | High | Consider avoiding outdoor exercise and shorten ventilation. |
| 100+ µg/m³ | Very high | Limit exposure, especially if you are in a vulnerable group. |
Local authorities may use different official categories and alert thresholds; always follow local public-health advice.
What can you do?
- Move strenuous outdoor activity away from busy roads and high-pollution periods.
- Ventilate briefly and intensively when outdoor levels are lower.
- If you have asthma or cardiovascular disease, follow medical advice and keep prescribed medication available.
- A well-fitting FFP2/FFP3 respirator filters particles much better than a loose surgical mask.
Frequently asked questions
What is the difference between PM10 and PM2.5?
PM2.5 particles are smaller and can penetrate deeper into the lungs. Every PM2.5 particle is also counted within PM10, but not every PM10 particle is PM2.5.
Why can winter air be worse?
Heating adds emissions, while temperature inversions can trap polluted air near the ground.
Does a mask protect against particles?
A properly fitted FFP2 or FFP3 respirator can filter a large share of airborne particles; fit is essential.