From roads to the air: The role of asphalt pavements on urban air quality

ABSTRACTUrban air pollution remains a persistent global health challenge, and recent studies show that asphalt pavements are far more dynamic atmospheric actors than previously assumed. Beyond serving as passive surfaces, they emit complex mixtures of volatile organic compounds (VOCs) whose oxidation in the atmosphere can efficiently trigger new particle formation (NPF) and contribute to secondary pollution in cities. Within a multi-year research effort led by IMT Nord Europe’s Department of Energy and Environment and collaborators, we combine controlled-chamber measurements with atmospheric modeling to unravel the emission profiles of different asphalt materials and quantify their oxidation-driven particle formation potential. Laboratory experiments performed under realistic temperature and relative-humidity conditions reveal clear dependencies in emission intensity and chemical composition, which translate into distinct NPF responses when introduced into oxidant-rich urban atmospheres. These experimental findings are then integrated into modeling frameworks to simulate how asphalt-derived precursors influence particle loadings and urban air quality on local to neighborhood scales. This unified experimental–modeling approach provides a comprehensive picture of the atmospheric implications of asphalt pavements and offers a pathway for evaluating future pavement formulations or mitigation strategies. By linking detailed laboratory chemistry with predictive tools, the work supports the development of informed, evidence-based road materials capable of limiting emissions and reducing the secondary pollutant burden in urban environments.