The impact of improved air quality on low birth weight and health inequalities in Spain from 2010 to 2018

Why clinicians should know about it

• Picked for Public Health, Environmental and Occupational Health (paper of the day, 19 July 2026).

Abstract

BACKGROUND: We aimed to estimate the association of air pollution and term low birth weight (LBW) by maternal education and assess the distributional impact of meeting European Union and World Health Organization air pollution targets and universal tertiary maternal education on LBW cases. METHODS: We analyzed administrative data on 1 409 084 term births in Spain (2010-18) and high spatial resolution estimates of maternal particulate matter with a diameter of 2.5 micrometers or less (PM2.5) and nitrogen dioxide (NO2) exposure. Single-exposure distributed lag non-linear models were used to estimate exposure-response functions (ERF) for LBW (<2500 g) overall and by maternal education. We then applied G-computation to estimate changes in LBW cases under counterfactual scenarios: target levels of PM2.5 (10 and 5 µg/m³) and NO2 (20 and 10 µg/m³), and universal tertiary maternal education. RESULTS: A 10 µg/m³ increase in PM2.5 and NO2 was associated with 6% [95% confidence interval (CI): 0%-11%] and 1% (95% CI: 0%-3%) higher odds of LBW. Relative to tertiary education, secondary and primary education were associated with increased LBW odds [1.32 (95% CI: 1.30-1.35); 1.76 (95% CI: 1.71-1.82)]. Meeting the 10 and 5 µg/m³ PM2.5 limits would have prevented 662 (95% CI: -4 to 1271) and 2032 (95% CI: -74 to 3900) LBW cases in 2010-18. Meeting the 20 and 10 µg/m³ NO2 limits would have prevented 432 (95% CI: -16 to 848) and 938 (95% CI: -50 to 1860) LBW cases in 2010-18. Universal attainment of tertiary education would have prevented over 9200 LBW cases. The primary maternal education group showed the highest shares of LBW cases, but they also experienced the largest relative reductions under air pollution intervention scenarios. CONCLUSIONS: Expanding access to higher education may yield large reductions in the burden of LBW. Reducing air pollution exposure could also meaningfully reduce LBW burden, particularly among infants from lower educated mothers, and contribute to narrowing related health inequalities.

Abstract as published, via PubMed.