Table 2. Summary statistics of population-weighted annual average concentrations across 215,491 Census Block Groups for the contiguous U.S., by pollutant and decadal year, based on predictions at Census Block centroids by using the “best” Integrated Empirical Geographic (IEG) models mostly using 3–30 geographic variables.
| Pollutant | Year | Percentile | Mean | SD | ||||
|---|---|---|---|---|---|---|---|---|
| 10 | 25 | 50 | 75 | 90 | ||||
| NO2 | 1980 | 7.4 | 12.1 | 19.9 | 27.9 | 36.8 | 21.3 | 11.7 |
| (ppb) | 1990 | 6.1 | 8.4 | 12.9 | 19.0 | 26.9 | 15.2 | 9.2 |
| 2000 | 5.6 | 7.8 | 11.8 | 16.7 | 23.2 | 13.3 | 7.5 | |
| 2010 | 3.3 | 4.7 | 7.2 | 10.8 | 15.8 | 8.5 | 5.1 | |
| SO2 | 1980 | 3.4 | 5.8 | 8.9 | 12.5 | 16.6 | 9.6 | 5.3 |
| (ppb) | 1990 | 2.0 | 3.0 | 4.6 | 7.0 | 9.2 | 5.3 | 3.0 |
| 2000 | 1.8 | 2.2 | 3.1 | 4.4 | 6.1 | 3.6 | 1.8 | |
| 2010 | 0.9 | 1.2 | 1.5 | 2.0 | 2.5 | 1.6 | 0.7 | |
| Ozone | 1980 | 39.0 | 45.4 | 51.3 | 57.3 | 63.6 | 51.1 | 9.6 |
| (ppb) | 1990 | 39.6 | 44.8 | 48.6 | 52.4 | 56.8 | 48.5 | 6.5 |
| 2000 | 40.2 | 43.9 | 49.0 | 53.6 | 57.1 | 48.5 | 6.7 | |
| 2010 | 37.7 | 43.1 | 46.6 | 49.6 | 52.2 | 45.6 | 6.0 | |
| CO | 1990 | 0.33 | 0.43 | 0.61 | 0.86 | 1.19 | 0.69 | 0.35 |
| (ppm) | 2000 | 0.29 | 0.35 | 0.43 | 0.55 | 0.74 | 0.48 | 0.20 |
| 2010 | 0.23 | 0.28 | 0.31 | 0.35 | 0.39 | 0.31 | 0.07 | |
| PM10 | 1990 | 19.8 | 22.7 | 25.9 | 30.2 | 36.8 | 27.5 | 7.9 |
| (μg/m3) | 2000 | 15.7 | 18.8 | 22.0 | 25.4 | 30.8 | 22.9 | 6.8 |
| 2010 | 12.8 | 15.2 | 18.3 | 21.5 | 24.1 | 18.4 | 4.6 | |
| PM2.5 | 2000 | 8.6 | 10.7 | 12.9 | 15.2 | 16.7 | 12.9 | 3.4 |
| (μg/m3) | 2010 | 6.3 | 7.9 | 9.6 | 10.8 | 12.1 | 9.4 | 2.2 |