王碧菡,廖婷婷,欧阳正午,蒋婉婷,桂柯,韩琳.2013-2017年成都冬季空气质量状况改善评估[J].环境科学学报,2019,39(11):3648-3658
2013-2017年成都冬季空气质量状况改善评估
- Assessment of the improvement of air quality situation in the winter of Chengdu from 2013 to 2017
- 基金项目：国家重点研发计划（No.2018YFC0214003）
- 王碧菡
- 成都信息工程大学大气科学学院, 高原大气与环境四川省重点实验室, 成都 610225
- 廖婷婷
- 成都信息工程大学大气科学学院, 高原大气与环境四川省重点实验室, 成都 610225
- 欧阳正午
- 成都信息工程大学大气科学学院, 高原大气与环境四川省重点实验室, 成都 610225
- 蒋婉婷
- 成都信息工程大学大气科学学院, 高原大气与环境四川省重点实验室, 成都 610225
- 桂柯
- 中国气象科学研究院大气成分研究所, 北京 100081
- 韩琳
- 成都信息工程大学大气科学学院, 高原大气与环境四川省重点实验室, 成都 610225
- 摘要：利用2013-2017年冬季成都市国家环境监测子站PM2.5小时数据，结合MICAPS常规气象观测数据及ERA-interim再分析资料，对成都市2013-2017年冬季空气质量状况、气象条件及近10年大气扩散能力进行综合评估.结果发现，2013-2017年成都冬季12月末-1月初易发生持续性重污染事件，2015-2017年冬季持续性重污染事件总天数较2013-2014年有所减少，2013年冬季PM2.5浓度值最高，达到（149.3±72.2）μg·m-3，2015年最低（（80.7±44.1）μg·m-3），5年内冬季PM2.5浓度值呈波动下降趋势，下降率为9.65%，成都市冬季空气质量状况总体有所改善.2013-2017年成都冬季日降水量清除率表明，大于1 mm的降水对PM2.5有明显清除作用，而弱风和低边界层（加权平均）对PM2.5的累积效应显著，2013和2016年空气质量较差由于累积气象主控导致，2015年空气质量较优是由于清除气象主控.综合PM2.5浓度、边界层高度、地面风速和降水等因子，使用2498个有效样本构建成都地区冬季空气停滞气象条件阈值经验公式，为地面风速小于2.2 m·s-1、边界层高度小于520 m且无有效降水（日降水量>1 mm）.以2015年冬季大气扩散条件为基准，量化同等扩散条件下减排对PM2.5的影响，结果显示减排有效，但近10年成都地区大气扩散能力有所下降，说明今后大气污染防控将面临更大的挑战.
- Abstract：The hourly monitoring data of concentration of fine particulate matters (PM2.5) in Chengdu, as well as the meteorological data of MICAPS, ERA-interim reanalysis data of ECMWF, were used in the study to assess the air quality, meteorological factors and atmospheric diffusion capacity in Chengdu during winter from 2013 to 2017. The continuous severe pollution events in winter mainly occurred in the period between the end of December and early January. The number of continuous severe pollution days was less in winter in 2015-2017 than that in 2013-2014. The concentration of PM2.5 presented a decreasing trend at a rate of 9.65% within five years in winter of Chengdu, with the highest level in 2013 winter((149.3±72.2) μg·m-3) and lowest in 2015 ((80.7±44.1) μg·m-3), which indicated that the air quality improved in Chengdu as a whole. There was an obvious scavenging effect on PM2.5 while the daily precipitation was more than 1mm. The concentration of PM2.5 accumulated significantly at the situation of weak winds and low boundary layer height (weighted average). The air quality was poor during winter in 2013 and 2016 due to meteorological factors which lead to the accumulation of pollutants. The air quality was better during winter in 2015 due to the meteorological factors which lead to the accumulation of pollutants. The factors such as PM2.5 concentration, boundary layer height, surface wind speed and precipitation were comprehensively calculated to obtain the empirical formula of the threshold of air stagnation in Chengdu. The formula was wind speed <2.2 m·s-1, boundary layer height <520 m and no effective precipitation (daily precipitation <1 mm). A decreasing trend from 2013 to 2017 of the PM2.5 mass concentration was estimated based on the atmospheric diffusion conditions in 2015, using a localized air stagnation criterion. The result indicated that the measures of reducing emission were effective. However, there was a slight decreasing trend of atmospheric diffusion capacity in recent 10 years in Chengdu area, which implied there might be a greater challenge the government has to face in order to improve the air quality in the future.
