Biogenic and anthropogenic contributions to urban terpenoid fluxes

作者：Erin F. Katz, Caleb M. Arata, Eva Y. Pfannerstill, Robert J. Weber, Darian Ng, Michael J. Milazzo, Heather Byrne, Hui Wang, Alex Guenther, Camilo Rey‐Sánchez, Joshua S. Apte, Dennis Baldocchi, Allen H. Goldstein · 发表于：Atmospheric chemistry and physics · 年份：2025 · DOI：10.5194/acp-25-15281-2025 · 被引用次数：5 · 研究领域：Atmospheric chemistry and aerosols、Indoor Air Quality and Microbial Exposure、Plant responses to elevated CO2

Abstract. Terpenoids influence atmospheric chemistry through rapid oxidation reactions which form secondary products including ozone and secondary organic aerosols (SOA). Source apportionment of terpenoids is complicated in urban environments because there are biogenic and anthropogenic sources. This study utilizes measured fluxes of isoprene, monoterpenes, and sesquiterpenes with MEGAN, a biogenic emissions model, and FIVE-VCP, an anthropogenic emissions inventory, to characterize urban terpenoid emissions. Volatile organic compound (VOC) mixing ratios were measured using a Vocus proton-transfer reaction mass spectrometer (PTR-MS) during the URBAN-EC (Urban Research on Biogenic and ANthropogenic Emissions of Carbon) study in Berkeley, California from May to November 2022. Fluxes were calculated using the eddy covariance technique. Median fluxes of isoprene, monoterpenes, and sesquiterpenes were 0.269, 0.182, and 0.013 nmol m−2 s−1 respectively. Terpenoids were 2 % of the measured molar flux, 26 % of OH reactivity flux, and 21 % of SOA formation potential. The MEGAN isoprene emission factor was 4.56 nmol (m2 leaf area)−1 s−1. MEGAN isoprene fluxes matched URBAN-EC distributions seasonally and diurnally, while MEGAN monoterpene and sesquiterpene fluxes had more pronounced seasonal trends and lower morning emissions relative to URBAN-EC. Weekday/weekend differences were used to determine if terpenoids had anthropogenic sources. Monoterpene and sesquiterpene fluxes were signific...