Table 2.
Distributions of vegetation measures (250-m buffer) among controls, by child and census tract sociodemographic characteristics
| Vegetation measure percentiles | ||||
|---|---|---|---|---|
| 25th | 50th | 75th | 90th | |
| Overall greenness (NDVI) | ||||
| Black, non-Hispanic | 0.17 | 0.25 | 0.32 | 0.41 |
| White, non-Hispanic | 0.10 | 0.18 | 0.35 | 0.52 |
| Hispanic | 0.11 | 0.19 | 0.28 | 0.37 |
| Public payment source—no | 0.17 | 0.26 | 0.36 | 0.47 |
| Public payment source—yes | 0.16 | 0.24 | 0.31 | 0.39 |
| Census tract population density—lowa | 0.22 | 0.31 | 0.42 | 0.52 |
| Census tract population density—higha | 0.08 | 0.13 | 0.18 | 0.23 |
| Census tract SES index—lowa | 0.18 | 0.26 | 0.32 | 0.38 |
| Census tract SES index—higha | 0.15 | 0.25 | 0.41 | 0.53 |
| Tree canopy cover (%) | ||||
| Black, non-Hispanic | 9.1 | 13.2 | 18.8 | 27.9 |
| White, non-Hispanic | 5.6 | 11.7 | 29.4 | 48.2 |
| Hispanic | 5.1 | 9.6 | 15.2 | 24.4 |
| Public payment source—no | 9.6 | 15.2 | 24.4 | 37.6 |
| Public payment source—yes | 8.1 | 12.2 | 17.8 | 26.4 |
| Census tract population density—lowa | 12.2 | 18.8 | 30.5 | 44.2 |
| Census tract population density—higha | 3.0 | 5.1 | 8.1 | 11.2 |
| Census tract SES index—lowa | 9.6 | 12.7 | 17.3 | 22.8 |
| Census tract SES index—higha | 9.6 | 22.3 | 37.1 | 49.7 |
| Grass/shrub cover (%) | ||||
| Black, non-Hispanic | 8.6 | 11.2 | 14.7 | 19.3 |
| White, non-Hispanic | 2.5 | 7.1 | 13.7 | 21.3 |
| Hispanic | 3.6 | 8.1 | 12.7 | 17.3 |
| Public payment source—no | 8.1 | 11.2 | 15.7 | 20.8 |
| Public payment source—yes | 7.6 | 10.7 | 13.7 | 18.3 |
| Census tract population density—lowa | 9.6 | 13.2 | 18.3 | 24.4 |
| Census tract population density—higha | 3.0 | 4.1 | 6.6 | 8.1 |
| Census tract SES index—lowa | 9.1 | 11.7 | 14.7 | 18.3 |
| Census tract SES index—higha | 6.1 | 9.6 | 14.7 | 20.3 |
| Impervious surface (%) | ||||
| Black, non-Hispanic | 64.5 | 72.5 | 78.6 | 82.8 |
| White, non-Hispanic | 48.3 | 77.7 | 85.5 | 91.1 |
| Hispanic | 70.0 | 78.3 | 84.0 | 89.2 |
| Public payment source—no | 55.5 | 70.0 | 78.3 | 83.8 |
| Public payment source—yes | 66.6 | 73.6 | 79.8 | 84.0 |
| Census tract population density—lowa | 47.8 | 62.6 | 72.7 | 80.6 |
| Census tract population density—higha | 80.0 | 84.2 | 88.2 | 90.9 |
| Census tract SES index—lowa | 68.0 | 72.5 | 77.2 | 82.9 |
| Census tract SES index—higha | 41.8 | 68.9 | 82.0 | 87.2 |
NDVI, normalized difference vegetation index; SES, socioeconomic status
a “low” indicates variable values ≤ 25th percentile; “high” indicates variable values > 90th percentile