Prenatal exposure to ultrafine particles adversely affects children’s health and development

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 coauthors synthesized the results of previous studies, reviews and meta-analyzes on the adverse health effects of the two little ones 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 enter the circulation and even cross the placental barrier, directly reaching the developing fetus.

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

Additionally, some of the studies have looked at ways in which the particles might cause the observed harmful health effects. The two main mechanisms documented in the literature are direct (ultrafine particles cross the placenta and enter the fetal circulation) and indirect (particles cause interactions that lead to oxidative stress, inflammation, epigenetic changes and endocrine disruption).

The researchers also looked at possible treatments and policies that might minimize or even reverse the harm associated with prenatal PM exposure. Green spaces such as parks and other areas with trees and foliage offer a range of benefits for the communities that own them, including less exposure to particles. Nutritional interventions, including maternal dietary changes and antioxidant and vitamin supplementation, may provide protective effects that are also associated with better health outcomes in children exposed to prenatal air pollution.

It is important to review all of the literature on such a large and common environmental exposure. This helps in the development of policies and intervention strategies. The timing of exposure, such as during pregnancy, is increasingly recognized as an important window of sensitivity. 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