| 摘要: |
| 为探究城郊细颗粒物（PM2.5）污染特征的差异及其成因，利用2022年盐都区城区和郊区ρ（PM2.5）数据，分析了城郊站点ρ（PM2.5）水平和日变化特征的差异，并从污染来源和传输影响两方面进行了成因初探。结果显示：2022年盐都郊区ρ（PM2.5）年均值较城区高23.1%；郊区站点ρ（PM2.5）日变化峰值更突出，春、夏、秋三季早晨峰值出现在06：00左右，明显早于城区站点。PM2.5特征组分质量浓度比值和化学质量平衡（CMB）模型模拟结果表明，城郊站点PM2.5的主要贡献源为移动源、燃煤源等，城区的餐饮源和郊区的生物质燃烧源也有贡献；此外，郊区站点受二次生成的影响要远大于城区站点。ρ（PM2.5）与城市热岛效应强度（UHII）间关系研究结果表明：郊区受热岛效应影响的程度相对城区更强；各季节郊区ρ（PM2.5）与UHII均呈负响应，UHII越强，郊区PM2.5的水平扩散能力越强，城郊PM2.5的垂直扩散能力差别越明显。后向气流轨迹分析结果表明：郊区受到来自西南（安徽中部、江苏中部）方向、东部（黄海、东海）方向以及高空下沉污染气团的影响明显强于城区，外来污染气团的输送也是郊区ρ（PM2.5）高于城区的重要原因。 |
| 关键词: 细颗粒物 城郊差异 来源解析 城市热岛效应 后向气流轨迹 盐都区 |
| DOI：DOI：10.3969/j.issn.1674-6732.2024.03.015 |
| 分类号:X51 |
| 基金项目:江苏省卓越博士后计划（2023ZB049）；盐城市基础研究计划指令性（面上）项目（YCBK2023004） |
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| Preliminary Exploration into the Urban suburban Differences in PM2.5 Pollution Characteristics and Their Causes in Yandu District |
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MA Chenhuang， WANG Jiancheng*， ZHANG Xiang， CHEN Rong， HU Yiwei， ZHANG Zhiman
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Yancheng Institute of Environmental Protection Technology and Engineering， Nanjing University， Yancheng，Jiangsu 224001， China
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| Abstract: |
| In order to investigate the differences in PM2.5 pollution characteristics between urban and suburban areas and their causes， the data on PM2.5 mass concentrations in urban and suburban areas of Yandu District in 2022 were used to analyze the differences in PM2.5 concentration levels and daily change characteristics between urban and suburban sites， and a preliminary investigation of the causes was carried out in terms of the sources of pollution and the effects of transmission. The annual average PM2.5 concentration in 2022 in suburban areas was higher than in urban areas， by 23.1%. The peak diurnal variation of PM2.5 concentration at suburban station was more prominent， and the peak morning concentration occurred around 06：00 am in spring， summer and autumn， which was significantly earlier than that at urban station. The PM2.5 characteristic component concentration ratios and Chemical Mass Balance（CMB） model simulation results showed that the contributing sources of PM2.5 at urban and suburban stations had similarities and specificities. The main contributing sources were mobile sources， coal combustion sources， etc.， and there were other sources with smaller contribution ratios such as restaurant sources and biomass combustion sources in urban and suburban stations respectively. Suburban station was much more influenced by secondary generation than urban station. The relationship between PM2.5 concentration and urban heat island intensity（UHII） showed that suburban areas were more strongly affected by the heat island effect than urban areas. Meanwhile， the suburban PM2.5 concentrations showed a negative response with UHII in all seasons. Moreover， the stronger the UHII， the stronger the horizontal diffusion ability of PM2.5 in suburban areas ，and the more obvious the difference in the vertical diffusion ability of urban and suburban PM2.5. The results of backward airflow trajectory analysis showed that suburban areas were significantly more influenced by pollution air masses from southwest（central Anhui and central Jiangsu）， east（Yellow Sea and East China Sea） and sinking air masses at high altitude than urban areas， and the transport of foreign pollution air masses were the main reason for higher PM2.5 concentrations in suburban areas than urban areas. |
| Key words: PM2.5 Suburban differences Source analysis Urban heat island Backward airflow trajectory Yandu district |
