Air Pollution and Epigenetics

Abstract

The health effects of ambient air pollution are well-described, but less is known about the biological mechanisms mediating these health effects. In recent years, the hypothesis that epigenetics may play a role in driving exposure-disease associations has gained traction, in part because epigenetic modifications are labile and may respond to environmental exposures in ways that directly affect gene transcription and disease risk. The purpose of this review is to provide an understanding of the latest evidence to support this hypothesis. The studies selected for this review were collected through a PubMed search for articles published between January 2010 and July 2013 using the following epigenetics keywords: epigenetics, histone, microRNA, and DNA methylation; along with air pollutant keywords: air pollution, benzo[a]pyrene, nitrogen dioxide, ozone, particulate matter 1.0 (PM1), particulate matter 2.5 (PM2.5), particulate matter 10 (PM10) and polycyclic aromatic hydrocarbon (PAH). A total of 38 original research articles were identified for our review. The scientific studies to date provide evidence that PAHs and PM2.5 may have modest effects on methylation levels of certain CpG sites within candidate genes of interest in cardiovascular and respiratory disease as well as cancer. However, the data remain too sparse to draw any meaningful conclusions with regard to histone modifications, miRNAs, or effects of other pollutants such as NO2, O3, and SO4.