The influence of OH concentration on SOA formation from isoprene photooxidation
The influence of OH concentration on SOA formation from isoprene photooxidation
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OH浓度对异戊二烯光氧化SOA形成的影响
DOI：
10.1016/j.scitotenv.2018.09.084
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发表时间：
2019
影响因子：
9.8
通讯作者：
Li Xuran
中科院分区：
文献类型：
--
作者：
Song Min;Zhang Chenglong;Wu Hai;Mu Yujing;Ma Zhuobiao;Zhang Yuanyuan;Liu Junfeng;Li Xuran
研究了异戊二烯光氧化产生的二次有机气溶胶 (SOA)，通过改变烟雾室中异戊二烯和 H2O2 的浓度来揭示 OH 浓度对 SOA 形成的影响。结果表明，OH浓度越高，可检测SOA质量浓度消耗的异戊二烯越少，例如，在OH浓度约为1.65×107moleculescm−3时，可检测SOA的最低异戊二烯消耗约为14.4ppb，而在OH浓度约1.65×107moleculescm−3下则需要数十ppb的异戊二烯消耗 <1.0×107moleculescm−3，在 OH 浓度为 7.2×105moleculescm−3 时，异戊二烯消耗量为 75.1ppb，甚至未观察到可检测到的 SOA。还发现，在大气相关条件下，对于给定的气溶胶负载 (M0)，SOA 产量随着 OH 浓度的增加而增加，证实 OH 浓度在异戊二烯光氧化形成 SOA 中发挥着重要作用。对于几乎相同的异戊二烯和H2O2初始反应物浓度，本研究获得的最大SOA产率（5.8%~42.8%）比之前的研究报告的结果高1.5~3.1倍，差异主要归因于本研究的反应体系中的OH浓度高于之前的研究。本研究中采用的 OH 浓度接近中午左右的真实大气中的浓度，因此从异戊二烯光氧化中获得的 SOA 产量可能具有代表性。
The formation of secondary organic aerosol (SOA) from isoprene photooxidation was investigated to reveal the influence of OH concentration on SOA formation through varying the concentrations of isoprene and H2O2in a smog chamber. The results indicated that the higher the OH concentration was, the less the isoprene consumed for the detectable SOA mass concentration, for example, the lowest isoprene consumption for the detectable SOA was about 14.4 ppb under the OH concentration of about 1.65 × 107molecules cm−3, whereas tens ppb of isoprene consumption were needed under the OH concentrations <1.0 × 107molecules cm−3, and even no detectable SOA was observed with isoprene consumption of 75.1 ppb under OH concentration of 7.2 × 105molecules cm−3. SOA yield was also found to increase with increasing OH concentration for a given aerosol loading (M0) at atmospherically relevant conditions, confirming that OH concentration played important role in SOA formation from isoprene photooxidation. The maximal SOA yields (5.8–42.8%) obtained by this study were a factor of 1.5–3.1 greater than those reported by previous study for the almost the same initial reactant concentrations of isoprene and H2O2, and the difference was mainly ascribed to the higher OH concentrations in the reaction systems of this study than those of previous study. The OH concentrations adopted in this study closed to those in the real atmosphere around noontime, and hence the SOA yield obtained from the isoprene photooxidation might be representative.