Formation of Low Volatility Organic Compounds and Secondary Organic Aerosol from Isoprene Hydroxyhydroperoxide Low-NO Oxidation
Formation of Low Volatility Organic Compounds and Secondary Organic Aerosol from Isoprene Hydroxyhydroperoxide Low-NO Oxidation
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DOI：
10.1021/acs.est.5b02031
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发表时间：
2015-09-01
影响因子：
11.4
通讯作者：
Canagaratna, Manjula R.
中科院分区：
文献类型：
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作者：
Krechmer, Jordan E.;Coggon, Matthew M.;Canagaratna, Manjula R.
在 FIXCIT 室研究期间，观察到气相低挥发性有机化合物 (LVOC)，是由异戊二烯 4-羟基-3-氢过氧化物 (4,3-ISOPOOH) 在低 NO 条件下氧化产生的。 LVOC 的减少直接对应于元素成分一致的二次有机气溶胶 (SOA) 的出现和生长，表明 LVOC 凝结（OA 低于 1 μ g m(-3)）。这代表了首次同时测量气相和颗粒相中异戊二烯氧化产生的低挥发性物质的冷凝。本研究中 SOA 的形成与之前描述的异戊二烯环氧二醇 (IEPDX) 的吸收是分开的。在室研究中将所有冷凝 LVOC 信号分配给 4,3-ISOPOOH 氧化意味着壁损失校正的非 IEPDX SOA 质量产率类似于 4%。与单萜氧化中极低挥发性VOC（ELVOC）构成有机气溶胶相比，异戊二烯体系中饱和浓度为10(-2)至10μg·m(-3)的LVOC是主要成分。这些 LVOC 对于低 OA 浓度环境中纳米颗粒的生长可能很重要。在SOAS-2013期间，美国东南部的大气中也观察到了在室内观察到的LVOC，具有预期的昼夜周期。这种以前未表征的气溶胶形成途径可能占 SOA 产量的 5.0 Tg yr(-1) 类似，即全球 SOA 的 3.3%。
Gas-phase low volatility organic compounds (LVOC), produced from oxidation of isoprene 4-hydroxy-3-hydroperoxide (4,3-ISOPOOH) under low-NO conditions, were observed during the FIXCIT chamber study. Decreases in LVOC directly correspond to appearance and growth in secondary organic aerosol (SOA) of consistent elemental composition, indicating that LVOC condense (at OA below 1 mu g m(-3)). This represents the first simultaneous measurement of condensing low volatility species from isoprene oxidation in both the gas and particle phases. The SOA formation in this study is separate from previously described isoprene epoxydiol (IEPDX) uptake. Assigning all condensing LVOC signals to 4,3-ISOPOOH oxidation in the chamber study implies a wall-loss corrected non-IEPDX SOA mass yield of similar to 4%. By contrast to monoterpene oxidation, in which extremely low volatility VOC (ELVOC) constitute the organic aerosol, in the isoprene system LVOC with saturation concentrations from 10(-2) to 10 mu g m(-3) are the main constituents. These LVOC may be important for the growth of nanoparticles in environments with low OA concentrations. LVOC observed in the chamber were also observed in the atmosphere during SOAS-2013 in the Southeastern United States, with the expected diurnal cycle. This previously uncharacterized aerosol formation pathway could account for similar to 5.0 Tg yr(-1) of SOA production, or 3.3% of global SOA.