Air quality alert levels (one hour averages) for PM10 on Montserrat
| PM10 (μg/m3) | Description | Action |
|---|---|---|
| <50 | Ash levels low | None |
| 51–100 | Ash levels raised | Those who have experienced effects on health during past dusty episodes, especially asthmatics, should ensure they have masks available |
| 101–300 | Ash levels very high | Masks should be worn |
| >300 | Ash levels alert | Masks should be worn and efforts made to reduce exposure |