Table 2.
Distribution of 1-year PM2.5 concentrations over all visits by calendar year.
| Year | Visits (n) | Mean (SD) | Median (25th percentile, 75th percentile) |
|---|---|---|---|
| 2000 | 141 | 10.5 (0.8) | 10.5 (9.9, 11.0) |
| 2001 | 245 | 11.8 (0.7) | 11.7 (11.3, 12.3) |
| 2002 | 173 | 11.8 (0.6) | 11.9 (11.5, 12.2) |
| 2003 | 106 | 11.7 (0.8) | 11.7 (11.4, 12.2) |
| 2004 | 169 | 10.8 (0.9) | 10.8 (10.4, 11.3) |
| 2005 | 193 | 10.8 (1.0) | 11.0 (10.4, 11.4) |
| 2006 | 126 | 10.2 (0.9) | 10.2 (9.7, 10.8) |
| 2007 | 116 | 9.3 (0.9) | 9.3 (9.0, 9.8) |
| 2008 | 147 | 10.1 (0.9) | 10.2 (9.7, 10.7) |
| 2009 | 104 | 9.0 (0.9) | 9.0 (8.6, 9.5) |
| 2010 | 93 | 8.0 (1.0) | 8.0 (7.5, 8.5) |
| 2011 | 102 | 8.4 (0.8) | 8.5 (8.1, 9.0) |
| PM2.5, particulate matter ≤ 2.5 μm in diameter. | |||