Air stagnation and its impact on air quality during winter in Sichuan and Chongqing, southwestern China
Air stagnation and its impact on air quality during winter in Sichuan and Chongqing, southwestern China
复制标题
川渝地区冬季空气停滞及其对空气质量的影响
DOI：
10.1016/j.scitotenv.2018.04.122
复制
发表时间：
2018-09-01
影响因子：
9.8
通讯作者：
Sun, Yang
中科院分区：
文献类型：
--
作者：
Liao, Tingting;Gui, Ke;Sun, Yang
由于不利的大气扩散条件，四川和重庆地区冬季遭受严重的雾霾天气。本研究利用再分析和降水数据集，利用开发的标准计算和区分空气停滞事件，并结合2013-2016年冬季PM2.5浓度数据分析空气停滞事件的发生对空气质量的影响。空气停滞事件发生频率最高的年份为2013年，最低的年份为2015年。四川盆地冬季气象条件倾向于形成不利的大气扩散条件，4个冬季空气停滞日数的平均发生频率高达76.6%。空气停滞事件对四川盆地西部和南部空气质量的影响最为明显。空气停滞日PM2.5平均浓度比非空气停滞日高41.9%。以2015年有利的大气扩散条件为基准，对PM2.5浓度进行调整，量化PM2.5对其他年份空气质量改善的贡献，结果显示，2013-2016年冬季，四川和重庆地区PM2.5水平总体下降约10.7%，表明大气污染物减排措施非常有效。此外，2007-2016年近10年空气停滞日数和事件发生频率增加，线性斜率分别为0.61 yr（-1）和0.26 yr（-1）。该研究显示，政府在改善冬季空气质量方面可能面临更大的挑战，应该更加关注成都、重庆和四川盆地南部城市的污染物排放减少。(C) 2018 Elsevier B.V.版权所有
The Sichuan and Chongqing regions suffer from severe haze weather in winter due to theunfavourable atmospheric diffusion conditions. Reanalysis and precipitation datasets were applied in this study to calculate and distinguish air stagnation events using a developed criterion, and the impacts of the occurrence of air stagnation events on air quality were analysed in combination with the PM2.5 concentration data for the winters of 2013-2016. The highest occurrence frequency of air stagnation events was observed in 2013, and the lowest, 2015. The meteorological conditions during winter in the Sichuan Basin were inclined to form unfavourable atmospheric diffusion conditions, and the occurrence frequency of air stagnation days was up to 76.6% on average during the four winters. The effects of air stagnation events on air quality were most obvious in the western and southern Sichuan Basin. The mean concentrations of PM2.5 during air stagnation dayswere higher by 41.9% than those during non-air stagnation days. The PM2.5 concentrations were adjusted using the favourable atmospheric diffusion conditions in 2015 as a baseline to quantify the PM2.5 contribution to the improvement of air quality in the other years, which revealed that the level of PM2.5 in the Sichuan and Chongqing regions was declining at a rate of approximately 10.7% overall during the winters of 2013-2016, implying that the air pollutant reductionmeasures have been highly effective. Furthermore, the occurrence frequency of air stagnation days and events were increased in recent ten years of 2007-2016, with linear slopes of 0.61 yr(-1) and 0.26 yr(-1), respectively. The study revealed that the government might face a greater challenge in improving the air quality over winter and should pay more attention to reduction of pollutant emission in areas of Chengdu, Chongqing and cities in the south of the Sichuan Basin. (C) 2018 Elsevier B.V. All rights reserved.