Table 2.
Group distribution statistics for daily activity-based exposure concentration and exposure error
| Exposure concentration (μg/m3) | Exposure error (%) | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Group | Values of n | Mean | Confidence interval | Min | Max | Mean | Confidence interval | Min | Max |
| Race/ethnicitya | 1,173 | ||||||||
| Black | 115 | 20 | (19.0–21.5) | 8.5 | 43 | 1 | (−1.1–3.3) | −64 | 34 |
| Hispanic | 29 | 18 | (15.9–19.2) | 11 | 28 | 5 | (1.3–9.6) | −8.9 | 45 |
| White | 1,029 | 16 | (16.0–16.6) | 7.0 | 41 | 4 | (3.3–4.4) | −32 | 58 |
| Incomeb | 1,131 | ||||||||
| Below poverty | 137 | 18 | (17.1–19.2) | 7.4 | 43 | 1 | (−0.6–2.6) | −64 | 45 |
| Middle income | 577 | 17 | (16.8–17.6) | 7.0 | 41 | 3 | (1.9–3.5) | −52 | 53 |
| Higher income | 417 | 16 | (15.6–16.5) | 7.4 | 32 | 6 | (4.6–6.5) | −31 | 58 |
| Age | 1,224 | ||||||||
| 5–18 years | 148 | 17 | (16.1–17.9) | 8.5 | 29 | 3 | (0.6–4.6) | −64 | 53 |
| 19–65 years | 665 | 17 | (16.6–17.4) | 7.0 | 41 | 5 | (4.2–6.0) | −48 | 58 |
| Over 65 years | 411 | 16 | (15.9–16.9) | 7.4 | 43 | 1 | (1.0–1.8) | −17 | 23 |
| Urbanicity | 1,224 | ||||||||
| Urban | 267 | 22 | (21.2–22.4) | 12 | 43 | 0 | (−1.3–0.9) | −64 | 25 |
| Suburban | 387 | 17 | (16.3–17.2) | 10 | 35 | 4 | (3.3–5.2) | −31 | 42 |
| Second city | 287 | 16 | (15.5–16.2) | 8.8 | 25 | 4 | (3.1–4.9) | −31 | 38 |
| Rural | 283 | 13 | (12.6–13.6) | 7.0 | 27 | 6 | (4.3–7.1) | −17 | 58 |
| Daily travel time | 1,224 | ||||||||
| More than 60 min | 452 | 17 | (17.0–17.8) | 8.5 | 41 | 8 | (6.5–8.8) | −32 | 58 |
| Up to 60 min | 533 | 17 | (16.2–17.1) | 7.6 | 43 | 2 | (1.0–2.4) | −64 | 42 |
| No travel | 239 | 16 | (15.3–16.7) | 7.0 | 35 | 0 | (0–0) | 0 | 0 |
aRacioethnic labels used here are shortened forms of the race and origin category labels used by the US Census. Category descriptions are available at www.census.gov. Note that placement in a category is by self-selection, and individuals may be categorized in multiple or no categories
bThe below poverty, middle-income, and higher-income labels refer to households with income below the poverty threshold, above the poverty threshold but less than $75,000 and $75,000 or above