Characterizing the confluence of air pollution risks in the United States

Abstract

The US National Research Council in 2004 recommended that the US Environmental Protection Agency “strive to take an integrated multipollutant approach to controlling emissions of pollutants that pose the most significant risks.” Several urban pilot studies have since explored the merits and feasibility of this technique. These studies found that such policies can achieve this policy goal but will confront both legal constraints and data limitations. The Clean Air Act prescribes certain requirements for air quality polices reducing common (or “criteria”) air pollutants including ground-level ozone and fine particles that differ from those affecting toxic air pollutants such as benzene; due in part to these requirements, policy makers have traditionally designed programs to characterize and mitigate risk on a pollutant-by-pollutant basis. Multipollutant policies are also greatly constrained by the emissions, air quality, and health data available to identify opportunities for reducing population risks across air pollutants. We introduce a novel approach to identify the confluence of particulate matter 2.5 μm and smaller (PM_2.5), ozone, and toxic air pollutant risk throughout the USA. We account for the federal statutes governing air pollution policy targeting these pollutants and address differences in the health data used to characterize the risks of these pollutants. We demonstrate a proof-of-concept technique for identifying areas of the USA where there may be a confluence of these risks. We argue that planners could use this approach as a resource as they achieve the goals identified by the National Research Council in 2004.