Table 3. Descriptive hourly air pollutant and meteorological data (lag0) on days that out-of-hospital cardiac arrests occurred in Copenhagen (1 January 2000–31 December 2010).
| Percentiles | Difference between case days and mean control days (95% CI)b | ||||||||
| No. hoursa | No. hours missing data | Mean | SD | 25th | 50th | 75th | IQR | ||
| PM10 (µg/m3) | 4556 | 1669 | 15.73 | 12.05 | 9.65 | 13.35 | 18.60 | 8.95 | −0.03 (−0.51; 0.45) |
| PM2.5 (µg/m3) | 4556 | 1878 | 10.31 | 8.52 | 6.20 | 8.73 | 12.10 | 5.90 | −0.01 (−0.37; 0.35) |
| PM10-2.5 (µg/m3) | 4556 | 2347 | 4.84 | 9.38 | 1.45 | 3.75 | 6.55 | 5.10 | 0.05 (−0.38; 0.47) |
| PAC (µm2/m3) | 4556 | 2393 | 200.74 | 143.26 | 96.18 | 163.92 | 270.89 | 174.71 | −5.96 (−12.85; 0.93) |
| PVC (µm3/m3) | 4556 | 2393 | 8.16 | 6.82 | 3.28 | 6.08 | 11.05 | 7.77 | −0.36 (−0.69; −0.03) |
| PNC (no./cm3) | 4556 | 2393 | 6629 | 4376 | 3619 | 5557 | 8474 | 4856 | 46 (−146; 238) |
| NOx(ppb) | 4556 | 258 | 14.75 | 11.82 | 7.07 | 11.58 | 18.35 | 11.28 | −0.16 (−0.52; 0.20) |
| NO2 (ppb) | 4556 | 258 | 11.44 | 7.00 | 6.14 | 9.87 | 15.06 | 8.92 | −0.01 (−0.22; 0.20) |
| O3 (ppb) | 4556 | 1712 | 25.94 | 12.31 | 17.57 | 26.20 | 34.11 | 16.54 | 0.22 (−0.14; 0.58) |
| CO (ppm) | 4556 | 295 | 0.296 | 0.187 | 0.195 | 0.250 | 0.333 | 0.138 | −0.003 (−0.006; 0.001) |
| Temperature (°C) | 4556 | 192 | 8.84 | 7.16 | 3.23 | 8.13 | 14.42 | 11.19 | −0.04 (−0.14; 0.07) |
| Relative humidity (%) | 4556 | 192 | 72.29 | 14.55 | 62.86 | 75.05 | 83.33 | 20.47 | −0.19 (−0.56; 0.18) |
SD: Standard deviation.
IQR: Interquartile range.
a
Of the 96432 hours (on 4018 days) during the study period, 4657 OHCAs occurred on 4556 hours (on 2753 days).
b
Differences between case hours and control hours are calculated by subtracting the average of the level on the associated control hours from the case hour. The average of these differences for the 4657 OHCA cases is then calculated.