Road Dust Research Project

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Research suggests that re-entrained road dust may be a major source of atmospheric particulate matter (PM), particularly in the western United States where arid conditions are more prevalent. As engines become cleaner and electric vehicles more common, road dust emissions are likely to become a dominant factor in near-road air quality. Being able to quantify these road dust emissions accurately will become more important in the foreseeable future. However, current methodologies to estimate road dust emissions are outdated, based on numerous assumptions, and lack the ability to fully quantify temporal and spatial variability. This research report summarizes the state-of-the-science for calculating road dust emission factors and provides recommendations for ways to update and improve those methods. Future research is needed to account for seasonal effects, changes to average driving speeds, geographic differences, and to update PM2.5-to-PM10 ratios (and investigate if those ratios are temporally and/or spatially dependent). Future research could also leverage more novel measurement techniques, such as mobile monitoring, utilize more advanced and accurate measurement equipment, and measure PM2.5 from road dust emissions directly.