The North China Plain (NCP) is the region that experiences serious aerosol pollution. A number of studies focus on aerosol pollution in urban regions in NCP, however, research on characterizing aerosols in rural NCP areas is comparatively limited. In this study, we deployed a thermodenuder high-resolution aerosol mass spectrometer (TD-HR-AMS) system at a rural site in NCP region in summer 2013 to characterize the chemical compositions and volatility of submicron aerosols (PM1). The average PM1 mass concentration was 51.2 ± 48.0µg m-3 and organic aerosol (OA) contributed most (35.4%) to PM1. Positive matrix factorization (PMF) analysis of OA measurements identified four OA factors including hydrocarbon-like OA (HOA, accounting for 18.4%), biomass burning OA (BBOA, 29.4%), less-oxidized oxygenated OA (LO-OOA, 30.8%) and more-oxidized oxygenated OA (MO-OOA, 21.4%). The volatility sequence of the OA factors was HOA > BBOA > LO-OOA > MO-OOA, consistent with their oxygen-to-carbon (O:C) ratios. Additionally, the mean concentration of organonitrates (ON) was 1.48–3.39 µg m-3, contributing 8.1–19% of OA based on cross validation of two estimated methods with the HR-ToF-AMS measurement. The correlation analysis shows that ON were more correlated with BBOA and black carbon emitted from biomass burning but poorly correlated with LO-OOA. And the volatility analysis for ON further confirms that particulate ON formation might be highly associated with primary emissions in rural NCP.

中文翻译：

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华北平原农村地区有机气溶胶的表征：来源、挥发性和有机硝酸盐

华北平原（NCP）是气溶胶污染严重的地区。许多研究集中在新冠肺炎城市地区的气溶胶污染，然而，对新冠肺炎农村地区气溶胶表征的研究相对有限。在这项研究中，我们于 2013 年夏季在 NCP 地区的一个农村地点部署了一个thermodenuder 高分辨率气溶胶质谱仪 (TD-HR-AMS) 系统，以表征亚微米气溶胶 (PM1) 的化学成分和挥发性。PM1 的平均质量浓度为 51.2 ± 48.0µg m-3，有机气溶胶 (OA) 对 PM1 的贡献最大 (35.4%)。OA 测量值的正矩阵分解 (PMF) 分析确定了四种 OA 因素，包括类烃 OA（HOA，占 18.4%）、生物质燃烧 OA（BBOA，29.4%）、氧化程度较低的含氧 OA（LO-OOA，30. 8%）和更多氧化的含氧 OA（MO-OOA，21.4%）。OA 因子的挥发顺序为 HOA > BBOA > LO-OOA > MO-OOA，与它们的氧碳 (O:C) 比一致。此外，基于两种估计方法与 HR-ToF-AMS 测量的交叉验证，有机硝酸盐 (ON) 的平均浓度为 1.48–3.39 µg m-3，占 OA 的 8.1–19%。相关性分析表明，ON与BBOA和生物质燃烧排放的黑碳相关性更高，但与LO-OOA相关性较差。ON 的波动性分析进一步证实颗粒 ON 的形成可能与农村 NCP 的初级排放高度相关。根据两种估计方法与 HR-ToF-AMS 测量的交叉验证，有机硝酸盐 (ON) 的平均浓度为 1.48–3.39 µg m-3，占 OA 的 8.1–19%。相关性分析表明，ON与BBOA和生物质燃烧排放的黑碳相关性更高，但与LO-OOA相关性较差。ON 的波动性分析进一步证实颗粒 ON 的形成可能与农村 NCP 的初级排放高度相关。根据两种估计方法与 HR-ToF-AMS 测量的交叉验证，有机硝酸盐 (ON) 的平均浓度为 1.48–3.39 µg m-3，占 OA 的 8.1–19%。相关性分析表明，ON 与 BBOA 和生物质燃烧排放的黑碳相关性更高，但与 LO-OOA 相关性较差。ON 的波动性分析进一步证实颗粒 ON 的形成可能与农村 NCP 的初级排放高度相关。