Abstract. To better understand the origins, atmospheric processes and seasonality of atmospheric aerosols in North China, we collected fine aerosols (PM_2.5) at an urban (Nankai District, ND) and a suburban (Haihe Education Park, HEP) sites in Tianjin from July 2018 to July 2019. The PM_2.5 studied for carbonaceous, nitrogenous and ionic components and stable carbon and nitrogen isotope ratios of total carbon (δ¹³C_TC) and nitrogen (δ¹⁵N_TN). On average, mass concentration of PM_2.5, organic carbon (OC), elemental carbon (EC) and water-soluble OC (WSOC found to be higher in winter than that in summer at both ND and HEP. SO₄²⁻, NO₃− and NH₄+ were dominant ions and accounted for 89 % and 87 % of the total ionic mass at ND and HEP respectively. NO₃− and NH₄+ peaked in winter and minimized in summer, whereas SO₄²⁻ was higher in summer at both the sites. δ¹³C_TC and δ¹⁵N_TN were −26.5−(−)21.9 ‰ and +1.01−(+)22.8 ‰, respectively, at ND and −25.5−(−)22.8 ‰ and +4.91−(+)18.6 ‰, respectively, at HEP. Based on seasonal variations in the measured parameters, we found that coal and biomass combustion emissions are dominant sources of PM_2.5 in autumn and winter, while biological and/or marine emissions are important in spring and summer in the Tianjin region, North China. In addition, our results implied that the secondary formation pathways of secondary organic aerosols in autumn/winter were different from that in spring/summer, i.e., they were mainly driven by NO₃ radicals in the former period.

中文翻译：

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测量报告：华北天津上空精细气溶胶化学成分及13C和15N同位素比值：全年观测

摘要。为了更好地了解华北地区大气气溶胶的起源、大气过程和季节性，我们于 2018 年 7 月在天津市（南开区，ND）和郊区（海河教育园，HEP）站点收集了细气溶胶 (PM _2.5 )至 2019 年 7 月。PM _{2.5研究了碳质、含氮和离子组分以及总碳 (δ} ¹³ C _TC ) 和氮 (δ ¹⁵ N _TN )的稳定碳氮同位素比。平均而言，在 ND 和 HEP，PM _2.5、有机碳 (OC)、元素碳 (EC) 和水溶性 OC (WSOC) 的质量浓度在冬季高于夏季。SO ₄^2-、NO ₃ - 和NH ₄ + 是主要离子，分别占ND和HEP总离子质量的89%和87%。NO ₃ - 和NH ₄ + 在冬季达到峰值，在夏季最小化，而SO ₄ ^2-在两个站点的夏季都较高。δ ¹³ C _TC和 δ ¹⁵ N _TN在 ND 和 -25.5-(-)22.8 ‰ 和 +4.91-(+)18.6 ‰ 分别为 -26.5-(-)21.9 ‰ 和 +1.01-(+)22.8 ‰ ，分别在 HEP。根据测量参数的季节性变化，我们发现煤炭和生物质燃烧排放是 PM _{2.5的主要来源}在秋季和冬季，而生物和/或海洋排放在华北天津地区的春季和夏季很重要。此外，我们的研究结果表明，秋冬季次生有机气溶胶的二次形成途径与春夏季不同，即前期主要由NO _{3自由基驱动。}