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Summary statistics of mean air pollutant concentrations in Boston, Massachusetts.
| Air Pollutant | Visit 1 | Visit 2 | ||||||
|---|---|---|---|---|---|---|---|---|
| n | Mean (SD) | min | max | n | Mean (SD) | min | max | |
| PNC (number/cm3) * | 209 | 17,000 (5800) | 4700 | 29,000 | 126 * | 8300 (5100) | 3900 | 27,000 |
| PM2.5 (µg/m3) | 270 | 7.30 (4.3) | 0.78 | 20.4 | 222 | 7.80 (3.7) | 2.38 | 20.9 |
| BC (µg/m3) | 261 | 0.68 (0.4) | 0.25 | 1.62 | 203 | 0.62 (0.3) | 0.18 | 1.59 |
Notes: * PNC values missing due to the CPC malfunctioning for part of clinic 2 (March 2011–August 2011).
