Developmental consequences of prenatal and early life exposure to air pollution



Infants exposed in utero to fine particulate air pollution and ground-level ozone, the main component of smog, are more likely to have poor birth outcomes, including stillbirth, intrauterine growth restriction, preterm birth, and low birthweight. Given that development of the brain and nervous system begin in utero and early life, it follows that exposure to air pollution during these sensitive windows may also affect a child’s neurological development. However, long-term data beginning at infancy is rare, so little is known about this potential relationship.


Researchers led by IRP investigator Pauline Mendola, Ph.D., found that young children who lived close to a major roadway (within 50 to 500 meters) were twice as likely to achieve a low score on a test of communications skills than those who lived further away (more than 1,000 meters). These children were also more likely to fail to meet developmental milestones if they were exposed in utero to larger amounts of ozone or fine particulate air pollution. In addition, children who had higher levels of exposure to ozone in the first three years of life appeared to experience more consistent and profound negative effects compared with children with lower exposures, and they were more likely to miss developmental milestones during screenings at 8, 24, and 30 months of age. These analyses improved on prior work by considering residential history and mothers’ work and daycare locations.


These findings suggest that exposure to air pollution in the first three years of life may adversely affect brain development in children. Thus, it is important to minimize exposure to air pollution, such as that caused by traffic exhaust, especially during pregnancy, infancy, and early childhood.


Ha S, Yeung E, Bell E, Insaf T, Ghassabian A, Bell G, Muscatiello N, Mendola P. (2019). Prenatal and early life exposures to ambient air pollution and development. Environ. Res. 174:170-175.

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This page was last updated on Friday, June 9, 2023