| Workplace* | Workplace/5 | Environmental | |
|---|---|---|---|
| *These standards are time weighted averages over 8 hours, and assume a 40 hour working week. | |||
| †These limits apply to the ISO convention for respirable dust; the limits that applied using the BMRC convention were 5000 μg/m3for respirable dust and 400 μg/m3for silica. | |||
| ‡Department for the Environment, Transport and the Regions Expert Panel on Air Quality Standards. | |||
| Respirable dust | |||
| HSE† | 4000 μg/m3 | 800 μg/m3 | 50 μg/m3 |
| EPAQS‡(PM10) | |||
| Crystalline silica | |||
| HSE† | 300 μg/m3 | 80 μg/m3 | 80 μg/m3 |
| ACGIH cristobalite | 50 μg/m3 | 10 μg/m3 | 10 μg/m3 |
| ACGIH quartz | 100 μg/m3 | ||