Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States.
Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States.
Environ Sci Technol. 2022 Apr 19;56(8):4806-4815. doi: 10.1021/acs.est.1c07354. Epub 2022 Apr 8.
Volatile chemical products (VCPs) have recently been identified as potentially important unconventional sources of secondary organic aerosol (SOA), in part due to the mitigation of conventional emissions such as vehicle exhaust. Here, we report measurements of SOA production in an oxidation flow reactor from a series of common VCPs containing oxygenated functional groups and at least one oxygen within the molecular backbone. These include two oxygenated aromatic species (phenoxyethanol and 1-phenoxy-2-propanol), two esters (butyl butyrate and butyl acetate), and four glycol ethers (carbitol, methyl carbitol, butyl carbitol, and hexyl carbitol). We measured gas- and particle-phase products with a suite of mass spectrometers and particle-sizing instruments. Only the aromatic VCPs produce SOA with substantial yields. For the acyclic VCPs, ether and ester functionality promotes fragmentation and hinders autoxidation, whereas aromatic rings drive SOA formation in spite of the presence of ether groups. Therefore, our results suggest that a potential strategy to reduce urban SOA from VCPs would be to reformulate consumer products to include less oxygenated aromatic compounds.
挥发性化学产品(VCPs)最近被认为是次生有机气溶胶(SOA)的潜在重要非常规来源,部分原因是减少了车辆尾气等常规排放。在这里,我们报告了一系列含氧官能团和分子主链中至少有一个氧的常见 VCPs 在氧化流动反应器中产生 SOA 的测量结果。这些包括两种含氧芳香族物质(苯氧乙醇和 1-苯氧基-2-丙醇)、两种酯(丁酸丁酯和乙酸丁酯)和四种乙二醇醚(乙二醇、甲基乙二醇、丁基乙二醇和己基乙二醇)。我们使用一系列质谱仪和颗粒尺寸仪器测量了气相和颗粒相产物。只有芳香族 VCPs 才能产生具有高收率的 SOA。对于无环 VCPs,醚和酯官能团促进了碎片化并阻碍了自动氧化,而芳香环尽管存在醚基团,仍促进了 SOA 的形成。因此,我们的结果表明,减少城市 SOA 来自 VCPs 的潜在策略可能是重新配方消费产品,以减少含氧芳香族化合物。