Chemical Characterization of Highly Functionalized Organonitrates Contributing to Night-Time Organic Aerosol Mass Loadings and Particle Growth
Chemical Characterization of Highly Functionalized Organonitrates Contributing to Night-Time Organic Aerosol Mass Loadings and Particle Growth
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DOI：
10.1021/acs.est.8b05826
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发表时间：
2019-02-05
影响因子：
11.4
通讯作者：
Mohr, Claudia
中科院分区：
文献类型：
--
作者：
Huang, Wei;Saathoff, Harald;Mohr, Claudia
挥发性有机化合物（VOC）与NO₃自由基的反应以及被氧化的VOC的活性中间体与NO的反应可导致高度官能化的有机硝酸盐（ON）的形成。我们提供了关于ON的定量和化学信息，这些ON对2016年7月 - 8月在德国西南部农村地区测量到的夜间高有机气溶胶（OA）质量浓度有贡献。使用气体和气溶胶过滤进样口与高分辨率飞行时间化学电离质谱仪（FIGAERO - HR - ToF - CIMS）耦合，分析了气相和颗粒相中ON的分子组成。我们发现夜间ON对OA质量的贡献更大。所鉴定的ON是高度官能化的，含有4到12个氧原子。每分子含5、7、10或15个碳原子的ON化合物的昼夜变化模式各不相同，这表明其潜在的前体VOC具有相应的行为。日落后ON的时间变化与超细颗粒数浓度的时间变化相关，这表明ON在该地点经常观测到的夜间新粒子形成（NPF）中具有潜在作用。我们估计日落后ON对新形成粒子质量增加的贡献为18 - 25%。我们的研究深入了解了农村大气中高度官能化的ON的化学成分，以及在生物源VOC排放占主导的地区人为排放对夜间二次有机气溶胶（SOA）形成的作用。
Reactions of volatile organic compounds (VOC) with NO3 radicals and of reactive intermediates of oxidized VOC with NO can lead to the formation of highly functionalized organonitrates (ON). We present quantitative and chemical information on ON contributing to high nighttime organic aerosol (OA) mass concentrations measured during July-August 2016 in a rural area in southwest Germany. A filter inlet for gases and aerosols coupled to a high-resolution time-of-flight chemical ionization mass spectrometer (FIGAERO-HR-ToF-CIMS) was used to analyze the molecular composition of ON in both the gas and particle phase. We find larger contributions of ON to OA mass during the night. Identified ON are highly functionalized, with 4 to 12 oxygen atoms. The diel patterns of ON compounds with 5, 7, 10, or 15 carbon atoms per molecule vary, indicating a corresponding behavior of their potential precursor VOC. The temporal behavior of ON after sunset correlates with that of the number concentration of ultrafine particles, indicating a potential role of ON in night-time new particle formation (NPF) regularly observed at this location. We estimate an ON contribution of 18-25% to the mass increase of newly formed particles after sunset. Our study provides insights into the chemical composition of highly functionalized ON in the rural atmosphere and the role of anthropogenic emissions for night-time SOA formation in an area where biogenic VOC emissions dominate.