A Systematic Literature Review Assessing the Inequities in Air Quality Monitor Placement

Previous studies have shown that a lack of air quality monitors in the US makes it difficult to understand air pollution at local scales. Access to local air pollution information can inform actions to reduce pollution and exposure that is detrimental to human health. Recognizing where exposure is concentrated helps determine where conditions need to be improved. The US Environmental Protection Agency (EPA) sets standards on air quality required by the Clean Air Act (CAA) to protect human health. Regulatory monitoring requires nonattainment areas (places where air quality exceeds the set threshold by the EPA) to take action, but only in places where there are monitors. This systematic review assesses if existing studies on the current placement of EPA regulatory air quality monitors provides equitable monitoring of air quality in the US. Existing studies find that monitoring is not distributed equitably across social groups and is concentrated in Whiter, wealthier, and urban neighborhoods. The articles reviewed in this study also found that unmonitored communities are more racially diverse. Nonetheless, it remains uncertain whether these disparities persist over time, representing a critical limitation of existing research reviewed in this systematic review.