Abstract The formation of secondary organic aerosol (SOA) from toluene can impact urban air quality and therefore human health. Most SOA studies have focused on OH chemistry; however recent work suggests that chlorine atoms (Cl) may affect tropospheric chemistry more than previously assumed. This work focuses on SOA formation from Cl-initiated oxidation of toluene under different conditions. The fast reaction between Cl and toluene enabled complete consumption of toluene in environmental chamber experiments and aging of the toluene SOA. A high resolution time-of-flight chemical ionization mass spectrometer was used to observe several generations of gas-phase products. The presence of nitric oxides (NOx) appears to delay the formation of later generation products. Data from an aerosol chemical speciation monitor suggest that all SOA formed had high oxidation state, and that the bulk organic composition was different for SOA from Cl-dominated reactions compared to SOA from OH-dominated reactions. Addition of oxidant after all toluene had been consumed did not result in a significant change in the organic aerosol oxidation state, suggesting that the system may have reached an oxidative end-point in the particle phase.

中文翻译：

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由氯引发的甲苯氧化形成氧化的有机化合物

摘要 甲苯形成的二次有机气溶胶 (SOA) 会影响城市空气质量，进而影响人类健康。大多数 SOA 研究都集中在 OH 化学上。然而，最近的工作表明，氯原子 (Cl) 对对流层化学的影响可能比以前假设的要大。这项工作的重点是在不同条件下由氯引发的甲苯氧化形成 SOA。Cl 和甲苯之间的快速反应使环境室实验中的甲苯完全消耗和甲苯 SOA 的老化。高分辨率飞行时间化学电离质谱仪用于观察几代气相产物。一氧化氮 (NOx) 的存在似乎会延迟下一代产品的形成。来自气溶胶化学形态监测器的数据表明，形成的所有 SOA 都具有高氧化态，并且与来自 OH 主导反应的 SOA 相比，来自 Cl 主导反应的 SOA 的主体有机组成不同。在所有甲苯消耗完后添加氧化剂不会导致有机气溶胶氧化态发生显着变化，这表明系统可能已达到颗粒相的氧化终点。