Schmedding Ryan, Ma Mutian, Zhang Yue, Farrell Sara, Pye Havala O T, Chen Yuzhi, Wang Chi-Tsan, Rasool Quazi Z, Budisulistiorini Sri H, Ault Andrew P, Surratt Jason D, Vizuete William
Department of Environmental Science and Engineering, Gillings School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 United States.
Aerodyne Research Inc., Billerica, Massachusetts 01821, United States.
Atmos Environ (1994). 2019;213:456-462. doi: 10.1016/j.atmosenv.2019.06.005.
Fine particulate matter (PM) is known to have an adverse impact on public health and is an important climate forcer. Secondary organic aerosol (SOA) contributes up to 80% of PM worldwide and multiphase reactions are an important pathway to form SOA. Aerosol-phase state is thought to influence the reactive uptake of gas-phase precursors to aerosol particles by altering diffusion rates within particles. Current air quality models do not include the impact of diffusion-limiting organic coatings on SOA formation. This work examines how -pinene-derived organic coatings change the predicted formation of SOA from the acid-catalyzed multiphase reactions of isoprene epoxydiols (IEPOX). A box model, with inputs provided from field measurements taken at the Look Rock (LRK) site in Great Smokey Mountains National Park during the 2013 Southern Oxidant and Aerosol Study (SOAS), was modified to incorporate the latest laboratory-based kinetic data accounting for organic coating influences. Including an organic coating influence reduced the modeled reactive uptake when relative humidity was in the 55-80% range, with predicted IEPOX-derived SOA being reduced by up to 33%. Only sensitivity cases with a large increase in Henry's Law values of an order of magnitude or more or in particle reaction rates resulted in the large statistically significant differences form base model performance. These results suggest an organic coating layer could have an impact on IEPOX-derived SOA formation and warrant consideration in regional and global scale models.
细颗粒物（PM）已知会对公众健康产生不利影响，并且是一种重要的气候作用力。二次有机气溶胶（SOA）在全球范围内对PM的贡献率高达80%，多相反应是形成SOA的重要途径。气溶胶相态被认为会通过改变颗粒内部的扩散速率来影响气相前体向气溶胶颗粒的反应性摄取。当前的空气质量模型并未考虑扩散限制有机涂层对SOA形成的影响。这项工作研究了α-蒎烯衍生的有机涂层如何改变由异戊二烯环氧二醇（IEPOX）的酸催化多相反应预测的SOA形成。在2013年南方氧化剂和气溶胶研究（SOAS）期间，利用从大烟山国家公园的Look Rock（LRK）站点进行的实地测量所提供的输入数据，对一个箱式模型进行了修改，以纳入考虑有机涂层影响的最新基于实验室的动力学数据。当相对湿度在55 - 80%范围内时，纳入有机涂层影响会降低模拟的反应性摄取，预测的源自IEPOX的SOA减少高达33%。只有亨利定律值大幅增加一个数量级或更多或者颗粒反应速率大幅增加的敏感性案例才会导致与基础模型性能有统计学上的显著差异。这些结果表明有机涂层层可能会对源自IEPOX的SOA形成产生影响，值得在区域和全球尺度模型中加以考虑。
