ENVIRONMENTAL HEALTH HAZARD INDEXSummary The environmental health hazard exposure index summarizes potential exposure to harmful toxins at a neighborhood level. Potential health hazards exposure is a linear combination of standardized EPA estimates of air quality carcinogenic (c), respiratory (r) and neurological (n) hazards with i indexing census tracts. Where means  and standard errors  are estimated over the national distribution.  Interpretation Values are inverted and then percentile ranked nationally. Values range from 0 to 100. The higher the index value, the less exposure to toxins harmful to human health. Therefore, the higher the value, the better the environmental quality of a neighborhood, where a neighborhood is a census block-group. Data Source: National Air Toxics Assessment (NATA) data, 2011. Related AFFH-T Local Government, PHA and State Tables/Maps: Table 12; Map 13. References: https://www.epa.gov/ttn/atw/natamain/ To learn more about the Environmental Health Hazard Index visit: https://www.hudexchange.info/resource/4868/affh-raw-data/Date of Coverage: 02/2018The Environmental Health Hazard Exposure Index summarizes potential exposure to harmful toxins at a neighborhood level. Shapefilehttps://purl.stanford.edu/yq267dc3411engUnited States. Department of Housing and Urban DevelopmentPublicAir quality managementEnvironmental healthHousing and healthBoundariesEconomyLocationSocietyEnvironmental Health Hazard Index, July 2020DatasetsUnited States2020Stanford