Abstract Real-time measurements of submicron aerosol species including sulfate, nitrate, ammonium, chloride, organics and black carbon were conducted from a regional site (Dianshan Lake) in the rural area of western Shanghai for 1 year from July 2015 to June 2016. An Aerosol Chemical Speciation Monitor (ACSM) and an Aethalometer were deployed to analyze the seasonal and diurnal variations of aerosol properties at 1-h time resolution. The ACSM and Aethalometer measurements of submicron particulate matter (PM1) concentration and composition agreed well with collocated measurements of PM2.5 using a Tapered Element Oscillating Microbalance, a Monitoring Instrument for Aerosols and Gases (MARGA) and a Sunset organic carbon and elemental carbon (OC/EC) analyzer. A rolling-window positive matrix factorization (RW-PMF) algorithm was applied to the ACSM mass spectra to examine organic aerosol (OA) sources and identified three factors representing hydrocarbon-like organic aerosol (HOA), more-oxidized oxygenated organic aerosol (MO-OOA) and less-oxidized oxygenated organic aerosol (LO-OOA), respectively. The annual average mass concentration of PM1 was 43.6 ± 29.9 μg m−3, with the seasonal average ranging from 32.3 ± 21.0 μg m−3 in summer to 60.3 ± 38.3 μg m−3 in winter. OA contributed the most to PM1 with a small seasonal difference (29–32%). More seasonal variations were observed in the mass fractions of nitrate (20–26%) and sulfate (18–26%) in PM1. Nitrate played an important role in PM pollution episodes since its fractional contribution to PM1 mass increased by approximately a factor of 3 (from ~10% to ~30%) from the lowest to the highest aerosol conditions. Photochemical production and gas-particle partitioning were the main drivers for secondary inorganic aerosol formation, leading to significant diurnal and seasonal cycles. The highest mass fractions of sulfate and nitrate occurred in summer and winter, respectively. Diurnal variation profiles of OA changed significantly between seasons, due to seasonal variations in dominant source contributions and meteorological conditions. HOA showed a predominant morning peak corresponding mainly to traffic emissions. Photochemical production of LO-OOA was observed in the afternoons of summer whereas a relatively flat diurnal cycle of MO-OOA suggested that it was mainly formed on a regional scale. Backtrajectory and potential source contribution function (PSCF) analyses indicated that the most important source region of LO-OOA was located in the coastal areas to the south of Shanghai while MO-OOA had a dominant transport pathway in the northwest direction.

中文翻译：

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使用气溶胶化学形态监测器在上海农村地区进行为期一年的实时观测对亚微米气溶胶进行化学表征和来源识别

摘要 2015 年 7 月至 2016 年 6 月，在上海西部农村地区的一个区域站点（淀山湖）对亚微米气溶胶物种包括硫酸盐、硝酸盐、铵盐、氯化物、有机物和黑碳进行了实时测量。部署了气溶胶化学形态监测器 (ACSM) 和风量计，以 1 小时时间分辨率分析气溶胶特性的季节性和昼夜变化。ACSM 和 Aethalometer 对亚微米颗粒物质 (PM1) 浓度和成分的测量与使用锥形元件振荡微量天平、气溶胶和气体监测仪器 (MARGA) 以及 Sunset 有机碳和元素碳的 PM2.5 的并置测量非常吻合。 OC/EC) 分析仪。将滚动窗口正矩阵分解 (RW-PMF) 算法应用于 ACSM 质谱以检查有机气溶胶 (OA) 来源，并确定了代表类烃有机气溶胶 (HOA)、更多氧化的含氧有机气溶胶 (MO) 的三个因素-OOA) 和氧化程度较低的含氧有机气溶胶 (LO-OOA)。PM1的年平均质量浓度为43.6±29.9 μg m-3，季节性平均值从夏季的32.3±21.0 μg m-3到冬季的60.3±38.3 μg m-3。OA 对 PM1 的贡献最大，季节性差异很小（29-32%）。在 PM1.5 中硝酸盐（20-26%）和硫酸盐（18-26%）的质量分数中观察到更多的季节性变化。硝酸盐在 PM 污染事件中发挥了重要作用，因为它对 PM1 质量的部分贡献从最低到最高气溶胶条件增加了大约 3 倍（从 ~10% 到 ~30%）。光化学产生和气体-颗粒分配是二次无机气溶胶形成的主要驱动因素，导致显着的昼夜和季节循环。硫酸盐和硝酸盐的最高质量分数分别出现在夏季和冬季。由于主要来源贡献和气象条件的季节性变化，OA的日变化剖面在季节之间发生了显着变化。HOA 显示了一个主要的早晨高峰，主要对应于交通排放。在夏季的下午观察到 LO-OOA 的光化学产生，而 MO-OOA 的相对平坦的昼夜循环表明它主要在区域范围内形成。回溯和潜在源贡献函数（PSCF）分析表明，LO-OOA 最重要的源区位于上海以南的沿海地区，而 MO-OOA 在西北方向上具有主导传输通道。