Breathing in the future: prenatal exposure to air pollution and infants' health outcomes in the USA

Objectives: This study aimed to investigate the impact of air pollution on birth outcomes in the USA over several decades.Study design: Approximately 70 million birth records were assessed for the years 1980-2020. This study focussed on seven measures of birth outcomes, including birth weight, low birth weight, very low birth weight, full-term birth weight, foetal growth, gestational age and very premature birth.Methods: An instrumental variable identification strategy was used that exploited within county month and within month-year of birth variations in exposure to precipitation-induced changes in air pollution.Results: Air pollution was found to have negative and large effects on a wide range of birth outcomes. The study findings suggest that a one-standard-deviation increase in ozone was associated with a 6.4% and 12.8% increase (from the mean) in the proportion of low birth weight and very preterm birth infants, respectively. Further analyses suggest that these effects were heterogeneous across trimesters of pregnancy and reveal larger impacts during the second and third trimesters.Conclusions: The results suggest that the ordinary least square estimates of previous studies considerably underestimate the true effects of pollution on birth outcomes. Policies that aim to improve the health capital of future generations should allocate more resources and initiatives to improving environmental air quality.(c) 2023 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study investigated the impact of air pollution on birth outcomes in the USA over several decades. The findings suggest that air pollution has negative effects on various birth outcomes, particularly increasing the proportion of low birth weight and very preterm infants. The study also reveals heterogeneity in the sensitivity to air pollution across trimesters of pregnancy.