The social distribution of neighborhood-scale air pollution and monitoring protection.

The potential for inequities between population subgroups in air pollution exposures and in regulatory protection because of small-scale intraurban differences in outdoor air pollution and air quality monitoring are studied here. The focus subgroups are blacks, Hispanics, whites, and the population living below poverty, with Tampa, FL, used as the case study area for quantitative analyses. A geographical database is developed for the surrounding county that includes population demographics, source locations, monitor locations, and air pollutant concentrations. Data included are residential population demographics at the block-group spatial scale from the year 2000 U.S. Census, U.S. Environmental Protection Agency (EPA) Toxic Releases Inventory source locations and air source release amounts, EPA Air Quality System monitoring data, and Florida major highway source locations and roadway traffic data. This database is applied for analysis of the spatial relationships between residence locations of population subgroups and outdoor air pollution surrogates. A quantitative index to evaluate the inequity between subpopulations is developed and applied. Findings include that blacks, Hispanics, and people living in poverty are disproportionately living closer to sources of air pollution and further from regulatory air quality monitoring sites compared with the overall county population. Conversely, whites are disproportionately living away from sources and near monitoring sites. Analysis of the regulatory monitoring guidelines indicates that recent changes in those guidelines may exacerbate existent inequities. The results suggest disparities in exposures to air pollution, disparities in regulatory monitoring representation, and the need for more monitoring and analyses at smaller spatial scales.