Molecules to Margins: Air Pollution Chemistry, Health Impacts, and Environmental Justice

Air pollution remains a major global health problem. Fine particulate matter (PM2.5) is associated with an estimated $1.1 trillion in annual health costs. This paper explores the composition of air pollutants, the role of environmental justice and health impacts on vulnerable populations. PM2.5 is composed mainly of organic matter (26 percent), sulfate (17.7 percent), nitrate (9.8 percent), ammonium (6.6 percent), and elemental carbon (6 percent), although these proportions vary by pollution source and geographic location. Studies have shown that secondary inorganic aerosols, traffic, industry and biomass burning are the main sources of air pollution. Environmental justice research has shown that Black Americans are exposed to PM2.5 concentrations 3 to 22 percent higher than the national average, and low-income households are exposed to concentrations 15 to 30 percent higher than average. Children, older adults and those with pre-existing health conditions are particularly vulnerable to adverse effects, including increased oxidative stress and inflammation. This paper argues that effective mitigation of air pollution requires integrated solutions that address pollutant reduction, equitable exposure, and the removal of barriers to clean air access.