Standards
The standards are listed in Title 40 of the Code of Federal Regulations Part 50.
| Pollutant | Type | Standard | Averaging Timea | Regulatory Citation |
|---|---|---|---|---|
| SO2 | Primary | 0.14 ppm (365 μg/m3) | 24-hour | 40 CFR 50.4(b) |
| SO2 | Primary | 0.030 ppm (80 μg/m³) | annual | 40 CFR 50.4(a) |
| SO2 | Secondary | 0.5 ppm (1,300 μg/m³) | 3-hour | 40 CFR 50.5(a) |
| PM10 | Primary and Secondary | 150 μg/m³ | 24-hour | 40 CFR 50.6(a) |
| PM2.5 | Primary and Secondary | 35 μg/m³ | 24-hour | 40 CFR 50.7(a) |
| PM2.5 | Primary and Secondary | 15 μg/m³ | annual | 40 CFR 50.7(a) |
| CO | Primary | 35 ppm (40 mg/m³) | 1-hour | 40 CFR 50.8(a)(2) |
| CO | Primary | 9 ppm (10 mg/m³) | 8-hour | 40 CFR 50.8(a)(1) |
| O3 | Primary and Secondary | 0.12 ppm (235 μg/m³) | 1-hourb | 40 CFR 50.9(a) |
| O3 | Primary and Secondary | 0.075 ppm (150 μg/m³) | 8-hour | 40 CFR 50.10(a) |
| NO2 | Primary and Secondary | 0.053 ppm (100 μg/m³) | annual | 40 CFR 50.11(a) and (b) |
| Pb | Primary and Secondary | 0.15 μg/m³ | Rolling 3 months | 40 CFR 50.12 |
- ^a Each standard has its own criteria for how many times it may be exceeded, in some cases using a three year average.
- ^b As of June 15, 2005, the 1-hour ozone standard no longer applies to areas designated with respect to the 8-hour ozone standard (which includes most of the United States, except for portions of 10 states).
- Source: USEPA
Read more about this topic: National Ambient Air Quality Standards
Famous quotes containing the word standards:
“The things a man has to have are hope and confidence in himself against odds, and sometimes he needs somebody, his pal or his mother or his wife or God, to give him that confidence. He’s got to have some inner standards worth fighting for or there won’t be any way to bring him into conflict. And he must be ready to choose death before dishonor without making too much song and dance about it. That’s all there is to it.”
—Clark Gable (1901–1960)
“Chief among our gains must be reckoned this possibility of choice, the recognition of many possible ways of life, where other civilizations have recognized only one. Where other civilizations give a satisfactory outlet to only one temperamental type, be he mystic or soldier, business man or artist, a civilization in which there are many standards offers a possibility of satisfactory adjustment to individuals of many different temperamental types, of diverse gifts and varying interests.”
—Margaret Mead (1901–1978)
“In this nation I see tens of millions of its citizens, a substantial part of its whole population, who at this very moment are denied the greater part of what the very lowest standards of today call the necessities of life. I see one third of a nation ill-housed, ill-clad, ill-nourished. The test of our progress is not whether we add more to the abundance of those who have much, it is whether we provide enough for those who have too little.”
—Franklin D. Roosevelt (1882–1945)