Development of a Multidimensional Housing and Environmental Quality Index (HEQI): Application to the American Housing Survey

Abstract Background: Substandard housing conditions and hazardous environmental exposures indoors contribute to significant morbidity and mortality worldwide. Housing indices that capture the multiple dimensions of healthy housing are important for tracking conditions over time and identifying vulnerable households. However, most indices focus on physical deficiencies and repair costs and omit indoor environmental exposures, as few data sources routinely collect this data at the national level. Methods: We developed a national, multidimensional Housing and Environmental Quality Index (HEQI) based on the World Health Organization’s Housing and Health Guidelines and applied it to the national American Housing Survey (AHS) 2019 data. The HEQI consisted of ten domains associated with poor health: indoor combustion sources, dampness and mold, pests and allergens, lead paint risk, high indoor temperatures, low indoor temperatures, household crowding, injury hazards, inadequate water and sanitation, and ventilation. We evaluated the validity and performance of the HEQI against three housing characteristics (i.e., year built, monthly rent costs, unit satisfaction rating) and two established indices (i.e., Adequacy index, Poor Quality Index). Results: Approximately 79% (92 million) of U.S. households reported at least one HEQI risk factor (mean per household: 1.5; range: 0,19). Common risk factors included indoor combustion sources (e.g. gas stoves, fireplaces) (62.0%), dampness and mold (15.4%), inadequate water and sanitation (11.7%), and injury hazards (11.6%). Prevalence of pest and allergens, low indoor temperature, and injury hazards were associated with older housing, lower rent costs, and worse unit satisfaction. Compared to established housing indices, the HEQI captured four new environmental domains and at least 62% (57.7 million) more households with environmental risk factors like mold, cockroaches, crowding, indoor combustion sources, and higher building leakage. Conclusions: Indoor environmental exposures are prevalent in U.S. households and not well-captured by established housing indices. The HEQI is a national, multidimensional tool that can be used to monitor indoor environmental exposures and housing quality trends in the U.S. The mounting evidence linking residential environmental exposures with adverse health outcomes underscore the need for this data in the AHS and other national surveys.