Contributions of primary sources to submicron organic aerosols in Delhi, India
Contributions of primary sources to submicron organic aerosols in Delhi, India
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DOI：
10.5194/acp-22-13631-2022
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发表时间：
2022-10
影响因子：
6.3
通讯作者：
S. Bhandari;Zainab Arub;G. Habib;J. Apte;Lea Hildebrandt Ruiz
中科院分区：
文献类型：
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作者：
S. Bhandari;Zainab Arub;G. Habib;J. Apte;Lea Hildebrandt Ruiz
摘要。印度德里的初级有机气溶胶（POA）浓度极高。以前很少有关于德里的来源分配研究捕获了生物质燃烧有机气溶胶（BBOA）和烹饪有机气溶胶（COA）对POA的影响。在另一篇论文中，我们开发了一种新的方法，利用正矩阵分解（PMF）的基本方法来进行按时间分解的源分配。我们称这种方法为“每日时间PMF”，并从统计上证明了这种方法相对于传统PMF的改进。本研究利用气溶胶化学形态监测仪（ACSM）的有机气溶胶测量数据，采用正矩阵分解（PMF）在两个季节（2017年冬季和季风季节）按时间分解，量化了BBOA、COA和类碳氢化合物有机气溶胶（HOA）的贡献。我们将EPA PMF工具与底层的多线性引擎（ME-2）一起部署，作为PMF求解器。我们还进行了详细的不确定度分析，以统计验证我们的结果。在冬季和季风季节，HOA都是POA的主要组成部分。除HOA外，COA是季风POA的主要组成部分，BBOA是冬季POA的主要组成部分。在季节（非时间）分析中，COA和不同类型的BBOA都没有得到解决。COA质谱（MS）分布与来自德里和世界各地的质谱分布一致，特别类似于高m/z 41的加热食用油的质谱。除了m/z 60的特征峰外，BBOA MS还具有非常突出的m/z 29，与以前在德里和木材燃烧源观察到的MS一致。除了分离POA之外，我们的技术还捕获了MS配置文件中随时间的变化，这是可用的源分配方法中的一个独特特性。除了主要因素外，我们还分离了两到三种含氧有机气溶胶（OOA）成分。当所有因素重新组合为总POA和OOA时，我们的结果与使用EPA PMF进行的季节性PMF分析一致。这项工作的结果可用于更好地设计针对德里有机气溶胶相关主要来源的政策。
Abstract. Delhi, India, experiences extremely high concentrations of primary organic aerosol (POA). Few prior source apportionment studies on Delhi have captured the influence of biomass burning organic aerosol (BBOA) and cooking organic aerosol (COA) on POA. In a companion paper, we develop a new method to conduct source apportionment resolved by time of day using the underlying approach of positive matrix factorization (PMF). We call this approach “time-of-day PMF” and statistically demonstrate the improvements of this approach over traditional PMF. Here, we quantify the contributions of BBOA, COA, and hydrocarbon-like organic aerosol (HOA) by applying positive matrix factorization (PMF) resolved by time of day on two seasons (winter and monsoon seasons of 2017) using organic aerosol measurements from an aerosol chemical speciation monitor (ACSM). We deploy the EPA PMF tool with the underlying Multilinear Engine (ME-2) as the PMF solver. We also conduct detailed uncertainty analysis for statistical validation of our results. HOA is a major constituent of POA in both winter and the monsoon. In addition to HOA, COA is found to be a major constituent of POA in the monsoon, and BBOA is found to be a major constituent of POA in the winter. Neither COA nor the different types of BBOA were resolved in the seasonal (not time-resolved) analysis. The COA mass spectra (MS) profiles are consistent with mass spectral profiles from Delhi and around the world, particularly resembling MS of heated cooking oils with a high m/z 41. The BBOA MS have a very prominent m/z 29 in addition to the characteristic peak at m/z 60, consistent with previous MS observed in Delhi and from wood burning sources. In addition to separating the POA, our technique also captures changes in MS profiles with the time of day, a unique feature among source apportionment approaches available. In addition to the primary factors, we separate two to three oxygenated organic aerosol (OOA) components. When all factors are recombined to total POA and OOA, our results are consistent with seasonal PMF analysis conducted using EPA PMF. Results from this work can be used to better design policies that target relevant primary sources of organic aerosols in Delhi.