Table 1.
Summary statistics of 24-hour average concentrations of PM2.5, four PM2.5 chemical components, meteorological conditions, and daily counts of hospital admissions for 2003–2007 by time-series data of complete and every third sampling days in the five-county Denver metropolitan area
| Category | Variable | N | Mean (SD) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| C1) | E12) | E23) | E34) | E4:STN5) | C | E1 | E2 | E3 | E4:STN | ||
| Pollutant (ug/m3) | PM2.5 | 1808 | 602 | 603 | 603 | 490 | 8.0 (5.1) | 7.9 (4.8) | 7.9 (5.1) | 8.1 (5.3) | 8.3 (5.7) |
| EC | 1809 | 603 | 603 | 603 | 490 | 0.5 (0.3) | 0.5 (0.4) | 0.5 (0.3) | 0.5 (0.3) | 0.5 (0.3) | |
| OC | 1809 | 603 | 603 | 603 | 490 | 3.1 (1.4) | 3.1 (1.4) | 3.1 (1.4) | 3.1 (1.3) | 3.1 (1.4) | |
| Sulfate | 1808 | 603 | 603 | 602 | 489 | 1.1 (1.0) | 1.0 (0.8) | 1.1 (1.0) | 1.1 (1.0) | 1.2 (1.2) | |
| Nitrate | 1808 | 602 | 603 | 603 | 490 | 1.0 (2.0) | 1.0 (1.9) | 1.1 (2.0) | 1.0 (2.0) | 1.1 (2.2) | |
|
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| Meteorological condition | Temperature (°C) | 1813 | 605 | 605 | 603 | 491 | 10.6 (−8.1) | 10.6 (−8.0) | 10.7 (−8.2) | 10.5 (−8.0) | 10.8 (−8.0) |
| Humidity (%) | 1813 | 605 | 605 | 603 | 491 | 54.6 (20.8) | 54.8 (20.8) | 54.3 (20.8) | 54.8 (20.7) | 54.7 (20.8) | |
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| Hospital admission (N) | Cardiovascular disease | 1826 | 609 | 609 | 608 | 494 | 44.8 (9.3) | 44.9 (9.4) | 44.9 (9.4) | 44.6 (8.9) | 44.1 (8.9) |
| Congestive heart failure | 1826 | 609 | 609 | 608 | 494 | 7.8 (3.2) | 7.8 (3.2) | 7.7 (3.2) | 7.8 (3.2) | 7.7 (3.2) | |
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| Respiratory disease | 1826 | 609 | 609 | 608 | 494 | 37.1 (14.6) | 36.9 (14.8) | 37.2 (14.3) | 37.3 (14.6) | 36.8 (14.4) | |
| Asthma | 1826 | 609 | 609 | 608 | 494 | 5.8 (3.0) | 5.7 (3.1) | 5.8 (3.0) | 5.8 (3.0) | 5.7 (3.0) | |
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| Weekday /Weekend | Weekday (N) | 1304 | 435 | 435 | 434 | 331 | |||||
| Weekend (N) | 522 | 174 | 174 | 174 | 163 | ||||||
| Weekday/Weekend (%) | 2.5 | 2.5 | 2.5 | 2.5 | 2.0 | ||||||
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| Total | 1826 | 609 | 609 | 608 | 494 | ||||||
1)
C: complete daily schedule
2)
E1: regular every third day schedule staring on January 1, 2003
3)
E2: regular every third day schedule staring on January 2, 2003
4)
E3: regular every third day schedule staring on January 3, 2003
5)
E4:STN: irregular every third day schedule equivalent to the sampling schedule (E3 except for six mismatched and 120 additional missing days) at an existing STN site 13 kilometers away from the DASH monitoring site