Environmental concentrations of respirable dust and cristobalite (μg/m3)
| Plymouth | Cork Hill | Salem | North | |
|---|---|---|---|---|
| Results shown as mean (range) of values measured using cyclone samplers between September 1996 and June 1997. The results of measurements made with co-located samplers suggest that there is an uncertainty of about 20% associated with individual determinations of concentration. | ||||
| September 1996 | ||||
| Respirable dust | 153 (30–310) | 183 (10–360) | 76 (20–270) | |
| Cristobalite | 11 (<10–19) | 11 (<10–31) | 6 (<10–19) | |
| No. samples | 12 | 12 | 7 | |
| October 1996 to May 1997 | ||||
| Respirable dust | 116 (9–544) | 75 (9–956) | 23 (<5–59) | 21 (<5–40) |
| Cristobalite | 9 (<5–57) | 3 (<5–16) | 3 (<5–10) | <5 |
| No. samples | 53 | 29 | 6 | 4 |
| June 1997 | ||||
| Respirable dust | 183 (107–292) | 236 (55–395) | 78 (16–480) | 45 (25–56) |
| Cristobalite | 16 (11–25) | 11 (<5–23) | <5 (<5–58) | <5 |
| No. samples | 3 | 8 | 26 | 12 |