Children’s environmental health, environmental justice and PM2.5 regulation in the US, 1997–2024

Children are uniquely susceptible to air pollution. US EPA is required to set National Ambient Air Quality standards that protect susceptible populations from air pollution within an “adequate margin.” Additionally, environmental justice communities are often disproportionately exposed to air pollution, therefore children living in these communities may experience increased vulnerability. PM2.5 contributes significantly to air pollution attributable morbidity and mortality. This research analyzes each PM2.5 rulemaking starting with the first in 1997 to determine for how children and children living in environmental justice communities were considered at each stage of the rulemaking process. We used content analysis to analyze all EPA PM 2.5 rulemakings. Publicly available rulemaking documents were searched to determine how EPA assessed the weight of evidence for Children’s Environmental Health (CEH) endpoints and how this evidence was used in later stages of rulemaking. We also analyzed EPA’s consideration of children in environmental justice analyses related to rulemaking. We used word count analysis to examine the relative emphasis on CEH and environmental justice in rulemaking over time. Finally, we examined if CEH evidenced was prioritized in EPA’s rulemaking rationales. The evidence base for CEH and PM 2.5 has expanded since 1997 but there are a limited number of CEH health endpoints designated as causal or likely causal in EPA’s weight of evidence assessments. CEH health effects in PM 2.5 benefits assessments have primarily been limited to respiratory effects and infant mortality. Consideration of environmental justice was limited until 2012 but expanded in 2024, however children have not been included in environmental justice health effects analyses. When CEH evidence was prioritized in rulemaking rationales, standards were strengthened. We find conflicting treatment of CEH in PM 2.5 standard setting. In some rulemakings CEH was prioritized while in others it was not. There has been limited consideration of environmental justice in PM 2.5 rulemaking and no rulemaking has accounted for the potential risk of adverse health effects for children living in environmental justice communities. EPA’s strict adherence to causal criteria for CEH endpoints, which can be difficult to study, may slow the adoption of protective standards. Further, policymakers should have access to more comprehensive data and information on PM2.5’s impact on CEH. Finally, due to its importance for lifelong health, we advocate for a consistent precautionary approach to CEH in NAAQs standard setting.