| 廊坊市秋冬季大气细颗粒物污染特征及来源解析 |
| 摘要点击 2268 全文点击 1739 投稿时间：2021-12-13 修订日期：2022-04-20 |
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| 中文关键词 廊坊市|大气颗粒物|化学组成|质量重构|源解析 |
| 英文关键词 Langfang|atmospheric particulate matter|chemical composition|mass closure|source apportionment |
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| 中文摘要 |
| 分析了2019~2020年秋冬季廊坊市北部、市区和南部这3个站点的大气细颗粒物及其化学组成.空间分布上,PM2.5浓度整体为:南部>市区>北部.PM2.5主要成分为有机物、硝酸盐、硫酸盐、铵盐、矿物组分、氯离子和元素碳,分别占PM2.5的质量分数为25.4%、21.5%、11.0%、11.5%、13.7%、3.5%和5.8%,金属元素及其他物质的质量分数分别为0.3%和7.2%;二次无机盐浓度呈现市区(28.7μg·m-3)高于北部(28.0μg·m-3)和南部(26.8μg·m-3)郊区的变化特征,而有机物(其浓度分别为16.6、13.0和18.5μg·m-3,由北向南,下同)、矿物组分(9.6、6.7和9.7μg·m-3)、氯盐(2.0、2.0和2.8μg·m-3)和元素碳(3.6、3.2和4.3μg·m-3)浓度呈现南部和北部郊区高于市区的变化特征.随着污染加重,二次无机盐的占比增加显著,其质量分数从38.7%增加到51.3%,表明二次无机盐是廊坊市大气污染的主控因子;有机物的贡献较高,但其质量分数随着污染加重有所降低,从27.3%降到了23.0%.应用PMF模型解析出廊坊市大气细颗粒物的5个主要来源,其中二次无机气溶胶的贡献最高,其贡献率高达41.9%;交通和燃煤同样是廊坊市大气颗粒物的重要来源,贡献率分别为19.9%和12.7%;工业和扬尘源的贡献率分别为9.1%和9.3%,其他未解析来源的贡献为7.1%.各区域的大气颗粒物来源较为接近,二次无机气溶胶和交通源的贡献率均为:市区>北部>南部,燃煤、扬尘和工业源的贡献率均为:南部>北部>市区.清洁天和污染天廊坊市大气细颗粒物的来源贡献差异较大,清洁天的主导来源为二次无机气溶胶、扬尘和交通源,而污染天则以二次无机气溶胶、交通和燃煤源贡献为主;随着污染加重,二次无机气溶胶和交通源的增加趋势最为显著,其贡献率分别从34.6%增加到45.7%和从17.3%增加到21.5%. |
| 英文摘要 |
| In this study, we report observations of various chemical species in PM2.5 samples that were collected between November 25, 2019 and March 31, 2020 in the northern, urban, and southern areas of Langfang, among which the concentrations of PM2.5 followed the order of southern>urban>northern. The abundance and chemical compositions of the particles in this study were temporally and spatially variable, with major contributions from organic matter (25.4%), nitrate (21.5%), sulfate (11.0%), ammonium (13.5%), and crustal matter (13.7%). The contributions of nitrate, sulfate, and ammonium were higher in the urban site compared with that in the southern and northern sites. On the contrary, organic matter and crustal matter exhibited much higher values in the southern and northern sites. In addition, the contributions of organic matter to the particle mass decreased from 27.3% to 23.0%, and the total contributions of sulfate, nitrate, and ammonium ions increased from 38.7% to 51.3% between clean and haze days, respectively. Source apportionment using positive matrix factorization showed five PM2.5 sources: secondary inorganic aerosol (41.9%), traffic emissions (19.9%), coal combustion (12.7%), industrial pollution (9.1%), and mineral dust (9.3%). The contributions of the first two factors followed the order of urban>northern>southern, whereas the contributions of the last three factors followed the order of southern>northern>urban. Further, the contributions of secondary inorganic aerosol, traffic emissions, and coal combustion were higher on haze days, whereas the contributions of industrial pollution and mineral dust were higher on clean days. |
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