Prenatal exposure to ultrafine PM has adverse effects on the health and development of children

Particulate matter (PM) is a major component of air pollution that is increasingly associated with long-term consequences for the health and development of children. In a study recently published in Nature’s Environmental Health and Preventive Medicine, Natalie Johnson, PhD, associate professor at Texas A&M University School of Public Health, and her co-authors synthesized findings from previous studies, reviews, and meta-analyses on the adverse health effects of the two smallest types of particles (PM ): fine (particles with an aerodynamic diameter less than 2.5 μm) and ultrafine (particles with an aerodynamic diameter less than 1 μm). Both types of PM can be inhaled deep into the lungs. Ultrafine particles have recently been shown to pass through the circulation and even cross the placental barrier, directly reaching the developing fetus.

A range of adverse health effects associated with fine particulate exposure have been reported in studies and reviews of human data, including low birth weight, asthma and other chronic respiratory conditions, cognitive and behavioral problems, obesity and diabetes. Research on the effects of prenatal exposure to ultrafine PM has not been as extensive, but a growing body of evidence shows similarities to effects associated with exposure to fine PM. Studies and reviews of data obtained from animal models have supported the results of human studies.

Additionally, some of the studies looked at possible ways that PM could cause the observed adverse health effects. The two major mechanisms documented in the literature are direct (ultrafine PM crosses the placenta and enters the fetal circulation) and indirect (PM causes interactions that result in oxidative stress, inflammation, epigenetic changes, and endocrine disruption).

The researchers also examined possible treatments and policies that could minimize or even negate the harms associated with prenatal PM exposure. Green spaces such as parks and other treed and leafy areas provide a range of benefits to the communities that have them, including less exposure to particulates. Nutritional interventions, including maternal dietary changes and antioxidant and vitamin supplementation, may have protective effects that are also associated with better health outcomes for children exposed to air pollution during pregnancy.

It is important to review all of the literature on such a large and common environmental exposure. This contributes to the development of policies and intervention strategies. The timing of exposure, such as during pregnancy, is increasingly recognized as an important window of susceptibility. So protecting the most vulnerable can have a huge impact on public health. »

Natalie Johnson, PhD, Associate Professor, Texas A&M University School of Public Health