De Minimis Emission Levels
40 CFR 93 ยง 153 defines de minimis levels, that is, the minimum threshold for which a conformity determination must be performed, for various criteria pollutants in various areas. The information is summarized here:
| Pollutant | Area Type | Tons/Year |
|---|---|---|
| Ozone (VOC or NOx) | Serious nonattainment |
50
|
| Severe nonattainment |
25
|
|
| Extreme nonattainment |
10
|
|
| Other areas outside an ozone transport region |
100
|
|
| Ozone (NOx) | Marginal and moderate nonattainment inside an ozone transport region |
100
|
| Maintenance |
100
|
|
| Ozone (VOC) | Marginal and moderate nonattainment inside an ozone transport region |
50
|
| Maintenance within an ozone transport region |
50
|
|
| Maintenance outside an ozone transport region |
100
|
|
| Carbon monoxide, SO2 and NO2 | All nonattainment & maintenance |
100
|
| PM-10 | Serious nonattainment |
70
|
| Moderate nonattainment and maintenance |
100
|
|
| PM2.5 Direct emissions, SO2, NOx (unless determined not to be a significant precursor), VOC or ammonia (if determined to be significant precursors) |
All nonattainment & maintenance |
100
|
| Lead (Pb) | All nonattainment & maintenance |
25
|