Table 2.
Summary of intersite partial Pearson correlations between St. Louis-Midwest Supersite/Tudor Ave. AQS data and data from other monitoring locations for each pollutant, 1 June 2001–30 April 2003.a
| Pollutants | No. of other sites | Median correlation (range) |
|---|---|---|
| Fine particles and components | ||
| 24-hr avg PM2.5 | 12b | 0.88 (0.46–0.95) |
| 24-hr avg PM2.5 | 3c | 0.88 (0.76–0.95) |
| Major ions | ||
| 24-hr avg SO42– | 3 | 0.90 (0.76–0.94) |
| 24-hr avg NO3– | 3 | 0.88 (0.75–0.90) |
| Carbon | ||
| 24-hr avg OC | 3 | 0.43 (0.38–0.69) |
| 24-hr avg EC | 3 | 0.47 (0.37–0.52) |
| Metals and metalloids | ||
| 24-hr avg Si | 3 | 0.96 (0.68–0.96) |
| 24-hr avg K | 3 | 0.71 (0.60–0.74) |
| 24-hr avg Ca | 3 | 0.35 (0.30–0.37) |
| 24-hr avg Fe | 3 | 0.54 (0.39–0.74) |
| 24-hr avg Cu | 3 | 0.03 (–0.09–0.05) |
| 24-hr avg Zn | 3 | 0.03 (–0.02–0.11) |
| 24-hr avg Pb | 3 | 0.08 (0.04–0.22) |
| Criteria gases | ||
| 8-hr max O3 | 13d | 0.85 (0.72–0.94) |
| 1-hr max CO | 3 | 0.62 (0.17–0.71) |
| 1-hr max NO2 | 8 | 0.64 (0.27–0.70) |
| 1-hr max SO2 | 10 | –0.03 (–0.10–0.12) |
| Abbreviations: avg, average; max, maximum. aThese are partial correlations, computed as the correlations between residuals from linear models for each of the pollutants that included all of the covariates in our epidemiologic models; all correlations exclude data from 4 July 2001, 4 July 2002, and 5 July 2002. bIncludes data from all sites at which PM2.5 was measured. cIncludes data from a subset of PM2.5 sites at which PM2.5 components were also measured (every 3 or 6 days). dOnly two sites other than Tudor Ave. provided year-round O3 data; restricting the analysis to these sites produced similar results: median, 0.84 (range, 0.82–0.87). | ||