Pollutant | Maximum allowable increase |
(micrograms per cubic meter) | |
PM-2.5 | |
annual arithmetic mean.......................................................................................... | 4 |
24-hr maximum........................................................................................................ | 9 |
Particulate matter: | |
PM-10, annual arithmetic mean........................................................................... | 17 |
PM-10, 24-hr maximum......................................................................................... | 30 |
Sulfur dioxide (SO2): | |
annual arithmetic mean......................................................................................... | 20 |
24-hr maximum...................................................................................................... | 91 |
3-hr maximum...................................................................................................... | 325 |
Nitrogen dioxide (NO2): | |
annual arithmetic mean......................................................................................... | 25 |
MAXIMUM ALLOWABLE INCREASE
[Micrograms per cubic meter]
Terrain Areas | ||
PERIODS OF EXPOSURE | Low | High |
24-hr maximum................................................................................................................ | 36 | 62 |
3-hr maximum.................................................................................................................. | 130 | 221 |
Mont. Admin. r. 17.8.825
75-2-111, 75-2-203, MCA; IMP, 75-2-202, 75-2-203, 75-2-204, MCA;