Evaluation of Transboundary Secondary Organic Aerosol in the Urban Air of Western Japan: Direct Comparison of Two Site Observations
Evaluation of Transboundary Secondary Organic Aerosol in the Urban Air of Western Japan: Direct Comparison of Two Site Observations
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DOI：
10.1021/acsearthspacechem.8b00106
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发表时间：
2018-12-01
影响因子：
3.4
通讯作者：
Hayashi, Masahiko
中科院分区：
文献类型：
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作者：
Irei, Satoshi;Takami, Akinori;Hayashi, Masahiko
来自亚洲大陆的跨界二次有机气溶胶（SOA）可能会对日本西部的城市空气质量产生重大影响，预计当地人为排放将成为气载颗粒有机物的主要来源。为了更好地理解跨界SOA的影响，我们在2012年3月和2010年12月同时进行了实地研究，在福冈市和江岛，分别代表了一个城市和背景网站的北方九州地区在日本西部，分别。在研究过程中，高时间分辨率（10分钟）的测量有机气溶胶（OA）和它的羧酸组分（m/z 44）的细颗粒物（PM 1. 0）进行了使用气溶胶质谱仪。独立地，每天在过滤介质上收集总悬浮颗粒物，并通过元素分析仪结合高精度同位素比质谱仪分析低挥发性水溶性有机碳（LV-WSOC）组分（预计包括SOA）的浓度及其稳定碳同位素比（Δ C-13）。结果表明，在研究期间，m/z 44和LV-WSOC的浓度高于福冈，而OA的幅度与福冈相当或低于福冈。两个研究中心之间m/z 44和LV-WSOC的日平均浓度比较显示，在两个研究期间具有高度相关性（r（2）高于0.72），而OA浓度相关性较低（r（2）高于0.47）。鉴于OA-m/z 44和LV-WSOC在福冈的跨界传输源，高相关性意味着主要贡献的m/z 44和LV-WSOC从福冈城市空气中的跨界来源。m/z 44和LVWSOC浓度之间的比较显示出高度相关性（R-2 > 0.91），线性回归的斜率相似（约0.91）。0.3在春季研究期间，两个地点的C）。此外，LV-WSOC作为OA在城市空气中的m/z 44分数的函数的Δ C-13图显示出系统的增加趋势，这是LV-WSOC中主要SOA和PM1.0中初级和次级OA的二元混合物的证据。尽管冬季研究的相同比较也显示两个地点的LV-WSOC和m/z 44之间存在高度相关性（R-2 > 0.85），线性回归的斜率有显著性差异（福冈和江的C分别为0.58和0.22 μ g μ g（-1）），C-13的δ图显示出随机变化，表明OA和/或LV-WSOC的复杂混合物。一系列的研究结果表明，SOA从跨界运输起源占主导地位的LV-WSOC，即使在日本西部的城市空气中，OA从本地起源是显着的。
Transboundary secondary organic aerosol (SOA) from the Asian continent may substantially influence the urban air quality of western Japan, where the local anthropogenic emissions are expected to be the major sources of airborne particulate organic matter. To better understand the influence of transboundary SOA, we conducted simultaneous field studies in March 2012 and December 2010 at sites in Fukuoka city and Fukue Island, representing an urban and a background site of the northern Kyushu region in western Japan, respectively. During the studies, high time resolution (10 min) measurements of organic aerosol (OA) and its carboxylate component (m/z 44) in fine particulate matter (PM1.0) were conducted using aerosol mass spectrometers. Independently, total suspended particulate matter was collected daily on filter media, and the concentration of the low-volatile water-soluble organic carbon (LV-WSOC) component, which was expected to include SOA, and its stable carbon isotope ratio (delta C-13) were analyzed by an elemental analyzer coupled with a high-precision isotope ratio mass spectrometer. Results showed that the concentrations of m/z 44 and LV-WSOC at Fukue were higher than those at Fukuoka, while the magnitude of OA at Fukue was comparable to or less than that at Fukuoka during the study periods. A comparison of the daily averaged concentrations of m/z 44 and LV-WSOC between the two sites showed high correlations during both study periods (r(2) higher than 0.72), while the OA concentrations were less correlated (r(2) higher than 0.47). Given that the OA, m/z 44, and LV-WSOC at Fukue were the transboundary transport origin, the high correlations imply the predominant contribution of m/z 44 and LV-WSOC from the transboundary origin in the Fukuoka urban air. A comparison between m/z 44 and LVWSOC concentrations showed high correlations (R-2 > 0.91) with similar slopes of linear regressions (ca. 0.3 mu g mu g(-1) of C) at both sites during the spring study. Furthermore, the delta C-13 plot of LV-WSOC as a function of the m/z 44 fraction in OA in the urban air showed a systematically increasing trend, which is evidence of predominant SOA in LV-WSOC and a binary mixture of primary and secondary OA in PM1.0. Although the same comparison for the winter study also displayed high correlations between LV-WSOC and m/z 44 at both sites (R-2 > 0.85), the slopes of the linear regressions were significantly different (0.58 and 0.22 mu g mu g(-1) of C for Fukuoka and Fukue, respectively) and the delta C-13 plot exhibited a random variation, indicating a complex mixture of OA and/or LV-WSOC. The series of findings suggest that SOA from the transboundary transport origin predominated LV-WSOC, even in the urban air of western Japan, where OA from the local origin was significant.