| 典型输送通道城市冬季PM2.5污染与传输变化特征 |
| 摘要点击 1087 全文点击 275 投稿时间：2023-01-17 修订日期：2023-03-14 |
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| 中文关键词 PM2.5 潜在源贡献分析法（PSCF） 浓度权重分析法（CWT） 气象-空气质量模型（WRF-CMAQ） 传输贡献 传输通量 |
| 英文关键词 PM2.5 potential source contribution function （PSCF） concentration-weighted trajctory（CWT） meteorological air quality model （WRF-CMAQ） transmission contribution transmission flux |
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| 中文摘要 |
| 以京津冀典型输送通道上的河北西南4个城市邯郸、邢台、衡水和沧州为例,分析了2019~2021年冬季3 a气象条件与PM2.5浓度变化特征,运用潜在源贡献分析（PSCF）和浓度权重分析（CWT）识别了研究期内4个城市PM2.5输送特征,基于气象-空气质量模型（WRF-CMAQ）传输矩阵法和传输通量法量化评估了邯郸、邢台、衡水和沧州与周边地区之间的PM2.5传输贡献,揭示了PM2.5传输净通量的垂直分布变化特征,并进一步识别4个城市两条PM2.5污染主要传输路径.结果表明,在研究期间,4个城市PM2.5浓度呈下降趋势,下降比例分别为45.85%、49.45%、42.40%和31.65%；邯郸和邢台潜在源贡献较大的区域主要分布在山西中南部（临汾、长治和晋中）和河南北部（新乡、开封和郑州）以及少部分内蒙古部分地区（PSCF>0.9）,衡水和沧州潜在贡献较大的区域主要集中在河北南部（邯郸、石家庄）、山西中部（太原、阳泉）和部分山东地区（PSCF>0.7）,CWT结果显示与PSCF类似；研究时段内4个城市冬季PM2.5均呈现本地贡献率（51.11%~62.99%）略高于区域贡献率（37.01%~48.89%）的特征,受水平湍流和垂直扩散等影响,4个城市2020年区域传输影响较其他年份稍高（0.50%~9.52%）,而2021年由于PM2.5浓度较低、气象因素影响等原因,区域传输影响较其他年份稍低（-2.15%~-9.52%）；邯郸、邢台、衡水和沧州这4个城市3 a冬季与周边区域总流入（流出）通量强度大小均为：2020年>2021年>2019年,对于总净通量而言,4个城市3 a冬季分别为邯郸：0.094、-0.070和0.087 kt·d-1；邢台：0.212、0.395和0.544 kt·d-1；衡水：-0.040、-0.228和0.185 kt·d-1；沧州：0.062、0.126和0.128 kt·d-1.在研究期间邯郸、邢台和沧州多作为污染传输受体,而衡水多为传输源体.在0~1 260 m之间,PM2.5净传输通量强度基本随着高度的升高而增大,不同时期不同城市最大净通量不同,邯郸最大净通量位于252~1 261 m,邢台最大净通量位于817 m,衡水最大净通量位于252~817 m,沧州最大净通量位于252~359 m；分析4个城市传输特征发现存在两条主要PM2.5传输方向,即西北-东南方向（山西→邯郸→河南、山东；石家庄→邢台→邯郸、山东；保定→沧州→山东）以及西南-东北方向（山西→邢台→衡水→沧州→渤海湾）. |
| 英文摘要 |
| Taking Handan, Xingtai, Hengshui, and Cangzhou, four cities in southwest Hebei Province along the Beijing-Tianjin-Hebei typical transport route, as examples, we analyzed the variation characteristics of 3a meteorological conditions and PM2.5 concentration in winter from 2019 to 2021 and used potential source contribution analysis (PSCF) and concentration weight analysis (CWT) to identify the transport characteristics of PM2.5 in the four cities during the study period. Based on the meteorological air quality model (WRF-CMAQ) transmission matrix method and transport flux method, the contribution of PM2.5 transport between Handan, Xingtai, Hengshui, and Cangzhou and the surrounding areas was quantitatively assessed; the vertical distribution characteristics of PM2.5 net transport flux were revealed; and the two main transport routes of PM2.5 pollution were further identified. The results showed that during the study period, the PM2.5 concentration decreased by 45.85%, 49.45%, 42.40%, and 31.65%, respectively. The potential source contribution of Handan and Xingtai was mainly distributed in south-central Shanxi (Linfen, Changzhi, and Jinzhong), northern Henan (Xinxiang, Kaifeng, and Zhengzhou), and a small part of Inner Mongolia (PSCF > 0.9). The potential contribution areas of Hengshui and Cangzhou were mainly concentrated in southern Hebei (Handan and Shijiazhuang), central Shanxi (Taiyuan and Yangquan), and some Shandong regions (PSCF > 0.7), and the CWT results were similar to those of PSCF. During the study period, the local contribution (51.11%-62.99%) was slightly higher than the regional contribution (37.01%-48.89%) during winter in the four cities. Affected by horizontal turbulence and vertical diffusion, the impact of regional transmission in 2020 was slightly higher than that in other years (0.50%-9.52%). In 2021, the influence of regional transmission was slightly lower than that of other years (-2.15%——9.52%) due to low PM2.5 concentration and meteorological factors. For Handan, Xingtai, Hengshui, and Cangzhou, the total inflow (outflow) flux intensity of the four cities during winter and the surrounding areas was in 2020 > 2021 > 2019. For the total net flux, the total inflow (outflow) flux intensity of the four cities in winter was 0.094, -0.070, and 0.087 kt·d-1 (Xingtai:0.212, 0.395, and 0.544 kt·d-1; Hengshui:-0.040, -0.228, and 0.185 kt·d-1; Cangzhou:0.062, 0.126, and 0.128 kt·d-1). During the study, Handan, Xingtai, and Cangzhou were mostly used as transport receptors, whereas Hengshui was mostly used as a transport source. In the range of 0-1 260 m, the net transport flux intensity of PM2.5 increased basically with the increase in height, and the maximum net flux of the various cities in different periods was different. The maximum net flux of Handan, Xingtai, and Hengshui was 252-1 261 m, 817 m, and 252-817 m, respectively. The maximum net flux in Cangzhou was 252-359 m. By analyzing the transmission characteristics of the four cities, it was found that there were two main transport directions of PM2.5, that is, the northwest-southeast direction (Shanxi → Handan → Henan and Shandong; Shijiazhuang → Xingtai → Handan and Shandong; Baoding → Cangzhou → Shandong) and the southwest-northeast direction (Shanxi → Xingtai → Hengshui → Cangzhou → Bohai Bay). |
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