Ambient Air Pollution, Housing Context, and Birth Outcomes Among Wisconsin Mothers.

Objectives: To assess the association between air pollution exposure and housing context during pregnancy and adverse birth outcomes.

Methods: We linked air pollution data from the Environmental Protection Agency and housing data from the American Community Survey with birth records from Wisconsin counties over a 9-year period. We calculated average daily pregnancy exposure to fine particulate matter and ozone and modeled its relationship to preterm birth, low birthweight and NICU admission, adjusting for individual characteristics and housing context.

Results: Ozone exposure and housing cost-burden had substantive and statistically significant negative associations with birthweight and gestational age, and positive associations with NICU admission, while a poor-quality housing environment had a significant negative effect on weeks of gestation. Fine particulate matter exposure had a negligible correlation with these outcomes.

Conclusions for practice: An additional tenth of one part-per-million daily average exposure to ozone is associated with a 33 g decrease in birthweight. This decrease in birthweight is about the same size as the association of gestational diabetes (32 g), larger than the association of chronic hypertension (22 g), and about 40% the size of the effect of smoking during pregnancy on birthweight (84 g). Given the magnitudes of the associations with atmospheric ozone and adverse birth outcomes, reducing atmospheric ozone should be a public health priority. Inclusion of controls for housing cost-burden and poor-quality housing reduces the magnitude of the association with mothers who identify as Black, suggesting the importance of these structural factors in understanding adverse birth outcomes by race.