Table 2.
Distribution of pollutants and meteorological variables in the Boston Metropolitan area.a
| Variable | N | Mean | SD | IQR | Correlation with PM2.5 |
| PM2.5 (μg/m3) | 345 | 10.9 | 8.4 | 8.1 | -- |
| Carbon Monoxide (ppm) | 352 | 0.44 | 0.19 | 0.20 | 0.35 |
| Sulfur Dioxide (ppb) | 352 | 4.8 | 3.5 | 3.4 | 0.18 |
| Nitrogen Dioxide (ppb) | 352 | 20.7 | 5.9 | 7.8 | 0.31 |
| Ozone (ppb) | 352 | 25.1 | 12.9 | 15.2 | 0.35 |
| Black Carbon (μg/m3) | 352 | 0.73 | 0.45 | 0.49 | 0.68 |
| Temperature (°C) | 352 | 11.0 | 10.2 | 16.3 | 0.37 |
| Dew Point (°C) | 352 | 4.2 | 10.7 | 16.1 | 0.38 |
| Barometric Pressure (mm Hg) | 352 | 761.4 | 5.9 | 7.4 | 0.05 |
aDistribution is over the entire study period (February 28, 2002 – February 14, 2003). PM2.5: particulate matter with aerodynamic diameter ≤2.5 μm; IQR: interquartile range.