Hazard Assessment of Chemical Air Contaminants Measured in Residences

Identifying air pollutants that pose a potential hazard indoors can facilitate exposure mitigation. In this study, we compiled summary results from 77 published studies reporting measurements of chemical pollutants were representative of concentrations in residences in the United States. These data were used to calculate representative mid-range and upper bound concentrations relevant to chronic exposures for 267 pollutants and representative peak concentrations relevant to acute exposures for 5 activity-associated pollutants. Representative concentrations are compared to available chronic and acute health standards for 97 pollutants. Fifteen pollutants are identified as contaminants of concern for chronic health effects in a large fraction of homes. Nine pollutants are identified as potential chronic health hazards in a substantial minority of homes and an additional nine are identified as potential hazards in a very small percentage of homes. Nine pollutants are identified as priority hazards based on robustness of reported concentration data and fraction of residences that appear to be impacted: acetaldehyde; acrolein; benzene; 1,3- butadiene; 1,4-dichlorobenzene; formaldehyde; naphthalene; nitrogen dioxide; and PM_2.5. Activity-based emissions are shown to pose potential acute health hazards for PM_2.5, formaldehyde, CO, chloroform, and NO₂.