Urban Oxidation Flow Reactor Measurements Reveal Significant Secondary Organic Aerosol Contributions from Volatile Emissions of Emerging Importance
Urban Oxidation Flow Reactor Measurements Reveal Significant Secondary Organic Aerosol Contributions from Volatile Emissions of Emerging Importance
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DOI：
10.1021/acs.est.9b06531
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发表时间：
2020-01-21
影响因子：
11.4
通讯作者：
Presto, Albert A.
中科院分区：
文献类型：
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作者：
Shah, Rishabh U.;Coggon, Matthew M.;Presto, Albert A.
移动的采样研究表明，在来源丰富的城市环境中，二次有机气溶胶（SOA）的水平有所提高。虽然这些增强可能来自快速反应的车辆排放，但最近有人假设非传统排放（挥发性化学产品和上游排放）正在成为城市SOA的重要来源。我们通过使用气体和气溶胶质谱与氧化流动反应器（OFR）相结合来测试这一假设，以表征受传统排放（车辆，生物源）和非传统排放（例如，油漆烟雾）。我们使用了两个SOA模型来评估我们观察到的SOA的车辆和生物源排放的贡献。观察到的SOA潜力和建模之间的最大差距发生在早晨的城市街道峡谷环境，我们的模型只能解释我们的观察的一半。VCP排放的贡献（例如，个人护理产品）在这种环境中的比例最高，这表明VCP是一个重要的缺失的前体来源，可以缩小建模和观察到的SOA潜力之间的差距。有针对性的OFR氧化非传统的排放物表明，这些排放物具有SOA的潜力，是类似的，如果不是更大，相比车辆排放。实验室实验表明，VCPs的SOA潜力存在很大差异，这意味着需要进一步表征这些非传统的排放。
Mobile sampling studies have revealed enhanced levels of secondary organic aerosol (SOA) in source rich urban environments. While these enhancements can be from rapidly reacting vehicular emissions, it was recently hypothesized that nontraditional emissions (volatile chemical products and upstream emissions) are emerging as important sources of urban SOA. We tested this hypothesis by using gas and aerosol mass spectrometry coupled with an oxidation flow reactor (OFR) to characterize pollution levels and SOA potentials in environments influenced by traditional emissions (vehicular, biogenic), and nontraditional emissions (e.g., paint fumes). We used two SOA models to assess contributions of vehicular and biogenic emissions to our observed SOA. The largest gap between observed and modeled SOA potential occurs in the morning-time urban street canyon environment, for which our model can only explain half of our observation. Contributions from VCP emissions (e.g., personal care products) are highest in this environment, suggesting that VCPs are an important missing source of precursors that would close the gap between modeled and observed SOA potential. Targeted OFR oxidation of nontraditional emissions shows that these emissions have SOA potentials that are similar, if not larger, compared to vehicular emissions. Laboratory experiments reveal large differences in SOA potentials of VCPs, implying the need for further characterization of these nontraditional emissions.