Assessing the impact of anthropogenic pollution on isoprene-derived secondary organic aerosol formation in PM(2.5) collected from the Birmingham, Alabama, ground site during the 2013 Southern Oxidant and Aerosol Study.
Assessing the impact of anthropogenic pollution on isoprene-derived secondary organic aerosol formation in PM(2.5) collected from the Birmingham, Alabama, ground site during the 2013 Southern Oxidant and Aerosol Study.
复制标题
DOI：
10.5194/acp-16-4897-2016
复制
发表时间：
2017
影响因子：
6.3
通讯作者：
Surratt JD
中科院分区：
文献类型：
--
作者：
Rattanavaraha W;Chu K;Budisulistiorini SH;Riva M;Lin YH;Edgerton ES;Baumann K;Shaw SL;Guo H;King L;Weber RJ;Neff ME;Stone EA;Offenberg JH;Zhang Z;Gold A;Surratt JD
在美国东南部，落叶树木排放的大量异戊二烯经过大气氧化，形成二次有机气溶胶 (SOA)，从而产生细颗粒物 (PM2.5)。实验室研究表明，人为污染物，如二氧化硫 (SO2)、氮氧化物 (NOx) 和气溶胶酸度，可以增强羟基自由基 (OH) 引发的异戊二烯氧化形成 SOA；然而，特定污染物增强环境 PM2.5 中异戊二烯 SOA 的机制仍不清楚。作为研究人为污染物如何影响异戊二烯衍生 SOA 形成的调查的一个方面，在 2013 年南方氧化剂和气溶胶研究 (SOAS) 期间，在阿拉巴马州伯明翰 (BHM) 地面站点收集了大量 PM2.5 过滤器样本。通过气相色谱-电子电离-质谱 (GC/EI-MS) 分析样品提取物，并进行三甲基硅烷化和超高效液相色谱联用电喷雾电离高分辨率四极杆飞行时间质谱 (UPLC/ESI-HR-QTOFMS)，以鉴定已知的异戊二烯 SOA 示踪剂。使用替代标准和真实标准量化的示踪剂与并置的气相和颗粒相数据以及东南气溶胶研究和表征 (SEARCH) 网络提供的气象数据进行比较，以评估人为污染对异戊二烯衍生的 SOA 形成的影响。这项研究的结果表明，异戊二烯衍生的 SOA 示踪剂贡献了相当大的有机物 (OM) 质量分数（约 7% 至约 20%）。异戊二烯衍生的 SOA 示踪剂与硫酸盐 () 相关（r2 = 0.34，n = 117），但与 NOx 不相关。在夜间观察到甲基丙烯酸环氧化物和羟甲基-甲基-α-内酯（统称为 MAE/HMML）衍生的 SOA 示踪剂与硝酸根生成 (P[NO3]) (r2 = 0.57，n = 40) 之间存在中等相关性，表明 NO3 自由基在形成这种 SOA 类型中具有潜在作用。然而，这些示踪剂与二氧化氮 (NO2) 的夜间相关性（r2 = 0.26，n = 40）较弱。仅在白天，臭氧 (O3) 与 MAE/HMML 衍生示踪剂（r2 = 0.72，n = 30）强烈相关，与 2-甲基四醇（r2 = 0.34，n = 15）中度相关，表明部分 SOA 形成可能来自城市地区的异戊二烯臭氧分解。未观察到气溶胶 pH 值与异戊二烯衍生的 SOA 之间存在相关性。气溶胶酸度和异戊二烯衍生的 SOA 之间缺乏相关性，这与酸度不是 BHM 位点异戊二烯 SOA 形成的限制因素的观察结果一致，因为在整个研究期间，气溶胶的酸性足以促进异戊二烯衍生的环氧化物的多相化学反应。总而言之，这些结果证实了之前的研究表明人为污染物会增强异戊二烯衍生的 SOA 形成。
In the southeastern US, substantial emissions of isoprene from deciduous trees undergo atmospheric oxidation to form secondary organic aerosol (SOA) that contributes to fine particulate matter (PM2.5). Laboratory studies have revealed that anthropogenic pollutants, such as sulfur dioxide (SO2), oxides of nitrogen (NOx), and aerosol acidity, can enhance SOA formation from the hydroxyl radical (OH)-initiated oxidation of isoprene; however, the mechanisms by which specific pollutants enhance isoprene SOA in ambient PM2.5 remain unclear. As one aspect of an investigation to examine how anthropogenic pollutants influence isoprene-derived SOA formation, high-volume PM2.5 filter samples were collected at the Birmingham, Alabama (BHM), ground site during the 2013 Southern Oxidant and Aerosol Study (SOAS). Sample extracts were analyzed by gas chromatography-electron ionization-mass spectrometry (GC/EI-MS) with prior trimethylsilylation and ultra performance liquid chromatography coupled to electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-QTOFMS) to identify known isoprene SOA tracers. Tracers quantified using both surrogate and authentic standards were compared with collocated gas- and particle-phase data as well as meteorological data provided by the Southeastern Aerosol Research and Characterization (SEARCH) network to assess the impact of anthropogenic pollution on isoprene-derived SOA formation. Results of this study reveal that isoprene-derived SOA tracers contribute a substantial mass fraction of organic matter (OM) (~ 7 to ~ 20 %). Isoprene-derived SOA tracers correlated with sulfate () (r2 = 0.34, n = 117) but not with NOx. Moderate correlations between methacrylic acid epoxide and hydroxymethyl-methyl-α-lactone (together abbreviated MAE/HMML)-derived SOA tracers with nitrate radical production (P[NO3]) (r2 = 0.57, n = 40) were observed during nighttime, suggesting a potential role of the NO3 radical in forming this SOA type. However, the nighttime correlation of these tracers with nitrogen dioxide (NO2) (r2 = 0.26, n = 40) was weaker. Ozone (O3) correlated strongly with MAE/HMML-derived tracers (r2 = 0.72, n = 30) and moderately with 2-methyltetrols (r2 = 0.34, n = 15) during daytime only, suggesting that a fraction of SOA formation could occur from isoprene ozonolysis in urban areas. No correlation was observed between aerosol pH and isoprene-derived SOA. Lack of correlation between aerosol acidity and isoprene-derived SOA is consistent with the observation that acidity is not a limiting factor for isoprene SOA formation at the BHM site as aerosols were acidic enough to promote multiphase chemistry of isoprene-derived epoxides throughout the duration of the study. All in all, these results confirm previous studies suggesting that anthropogenic pollutants enhance isoprene-derived SOA formation.
登录
查看更多内容
影响因子：
6.3
作者：
Chan, A. W. H.;Chan, M. N.;Seinfeld, J. H.
通讯作者：
Seinfeld, J. H.
影响因子：
11.4
作者：
Ding, Xiang;Zheng, Mei;Wang, Xinming
通讯作者：
Wang, Xinming
影响因子：
1.5
作者：
KAMENS, RM;GERY, MW;COLE, EI
通讯作者：
COLE, EI
DOI：
10.1017/cbo9781107415324.016
发表时间：
2014-01-01
期刊：
CLIMATE CHANGE 2013: THE PHYSICAL SCIENCE BASIS
影响因子：
--
作者：
Boucher, Olivier;Randall, David;Wyant, Matthew
通讯作者：
Wyant, Matthew
影响因子：
11.4
作者：
Carlton, Annmarie G.;Bhave, Prakash V.;Houyoux, Marc
通讯作者：
Houyoux, Marc