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Breakpoints and Associated Visibility for Particulate Concentrations
Health Effect Categories |
Visibility (miles)3 |
24-Hour
BAM (ug/m3) 1 |
8-Hour
BAM (ug/m3) 2 |
1-Hour BAM (ug/m3) 3 |
|
|---|---|---|---|---|---|
| Hazardous | < 1.3 | >135.4 | > 193.4 | > 338.5 | |
| Very Unhealthy | 2.1 - 1.3 | 80.5 - 135.4 | 115.0 - 193.4 | 201.1 - 338.5 | |
| Unhealthy | 5.0 - 2.2 | 35.5 - 80.4 | 50.7 - 114.9 | 88.6 - 201.0 | |
| Unhealthy for Sensitive Groups | 8.7 - 5.1 |
20.5 - 35.4 |
29.2- 50.6 |
51.1 - 88.5 |
|
| Moderate | 13.3 - 8.8 | 13.5 - 20.4 | 19.2 - 29.1 | 33.6 - 51.0 | |
| Good | > 13.4 + | 0.0 - 13.4 | 0.0 - 19.1 | 0.0 - 33.5 | |
- Washington State Department of Ecology, Washington Air Quality Advisory (2007), at https://fortress.wa.gov/ecy/enviwa.
- Applied U.S. EPA SCREEN adjustment factor for 8-hour, 0.7,
multiplied
to the 24-hour PM-2.5 Pollutant Standards Index. - John Coefield, Cyra Cain, Montana Department of Environmental Quality empirical study (July 2000) presented at Fire, Smoke and Health Workshop, Seattle, WA, June 5 - 6, 2001.
