Early life exposure to air pollution: how bad is it?

Abstract

Increasing concentrations of air pollution have been shown to contribute to an enormity of adverse health outcomes worldwide, which have been observed in clinical, epidemiological, and animal studies as well as in vitro investigations. Recently, studies have shown that air pollution can affect the developing fetus via maternal exposure, resulting in preterm birth, low birth weight, growth restriction, and potentially adverse cardiovascular and respiratory outcomes. This review will provide a summary of the harmful effects of air pollution exposure on the developing fetus and infant, and suggest potential mechanisms to limit the exposure of pregnant mothers and infants to air pollution.

Figure 1. Sources and divisions of PM

PM represents a class of heterogeneous substances that exist as discrete particles, combining to form one component of air pollution. PM can be divided into three different categories based on size range; coarse, fine, and ultrafine. Both human and biogenic sources produce constituents of PM, and PM exposure has become a growing field for research as many adverse health consequences have been related to PM exposure.

Figure 2. Pathways and impacts of PM exposure

PM is a major constituent of air pollution that is comprised of particles exhibiting three different size ranges. A number of cardiovascular effects have been related to increased levels of PM exposure. Studies have also demonstrated that fetal PM exposure may result in a host of developmental conditions including Intrauterine Growth Retardation (IUGR), low birth weight (LBW), preterm birth, and infant mortality. The mechanisms of effect following PM exposure can be characterized by the onset of oxidative stress, which causes placental and endothelial dysfunction. This dysfunction can lead to the development of a number of cardiovascular and respiratory symptoms.