A peer-reviewed study led by researchers at the University of California, Riverside, found that emissions from in-place asphalt pavements are minimal, localized and more than 250 times lower than previously reported estimates.
Published in ACS ES&T Air, the study combined laboratory testing with measurements from existing pavements exposed to real-world conditions. Researchers evaluated asphalt samples under realistic temperatures and sunlight, as well as the formation of secondary organic aerosols (SOAs), which can form when emitted chemicals react in the atmosphere.
The findings indicate that emissions primarily originate at the pavement surface rather than from the bulk asphalt material. Researchers also noted that earlier studies often relied on small, uncompacted asphalt samples rather than pavement in service.
The study was led by David Cocker, professor and chair of UCR's Department of Chemical and Environmental Engineering, and conducted through the university's Center for Environmental Research and Technology.
Commissioned by the Asphalt Institute, National Asphalt Pavement Association, Eurobitume and State Asphalt Pavement Associations Inc., the research provides additional data for evaluating asphalt pavement emissions and their potential effects on air quality.
Researchers concluded that, under the conditions evaluated, in-place asphalt pavement is not a significant source of urban smog-forming or other chemical atmospheric emissions.
