Background An emerging body of evidence suggests that ambient levels of air pollution
during pregnancy are associated with fetal growth. Objectives We examined relationships
between birth weight and temporal variation in ambient levels of carbon monoxide, nitrogen
dioxide (NO2), sulfur dioxide (SO2), ozone, particulate matter≤ 10 μm in diameter
(PM10),≤ 2.5 μm (PM2. 5), 2.5 to 10 μm (PM2. 5–10), and PM2. 5 chemical component
measurements for 406,627 full-term births occurring between 1994 and 2004 in five central …

Methods: We used vital records data to construct a retrospective cohort of 406,627 full-term
births occurring between 1994 and 2004 in five central counties of metropolitan Atlanta,
USA. We examined the relationship between birth weight and temporal variation in ambient
levels of carbon monoxide (CO), nitrogen dioxide (NO 2), sulfur dioxide (SO 2), ozone (O 3),
PM 10 (particulate matter< 10 μm in diameter), PM 2.5 (particulate matter< 2.5 μm in
diameter) and speciated PM 2.5 measurements. Daily pollutant levels in five-county Atlanta …