乌鲁木齐市大气污染治理成效的综合评估分析

2012~2013年乌鲁木齐采用了以煤改气为主的大气环境治理措施.利用2009~2014年冬季主要污染物浓度、1993~2014年的直接辐射、能见度、霾日数据,并参考相关文献,从大气环境的化学属性、物理属性两个方面评估煤改气等工程措施对乌鲁木齐市大气环境的改善效果.结果表明, 2013~2014年两个冬季乌鲁木齐市主要污染物PM₁₀、SO₂、NO₂浓度比煤改气前期(2009~2011年冬季)各自下降了26.1%、80.2%、11.6%;细颗粒物PM_2.5中水溶性物质的总浓度比例下降了20.57%.煤改气工程前后PM_2.5中可溶性离子浓度排名前三位的均是SO₄^2-、NH₄⁺和NO₃^-,但后期SO₄^2-和NH₄⁺占据PM_2.5质量浓度比例比前期下降近一半,NO₃^-质量浓度比例变化不大.从大气物理特性来看,煤改气等工程之后乌鲁木齐冬季直接辐射量提高,且2014/2015年冬季的直接辐射量是过去23年中第二个峰值;2012/2013年冬季能见度平均增加了5.7km,是1997年以来的最大值.与上年度同期相比,增幅达35.0%;2012/2013年冬季霾日数比上年度同期减少了15d,降幅达50%.上述结果说明乌鲁木齐市的大气环境得到了一定程度的改善.

Evaluation and analysis on the effects of air pollution control in Urumqi

Measures mainly based on the Coal to Gas Engineering (CTGE) for heating between 2012 and 2013 were taken to improve the air quality in Urumqi. In this paper, a comprehensive study was conducted to evaluate the effects of these measures on atmospheric environment in Urumqi by using the data of the concentrations of major air pollutants during wintertime of 2009~2014, the direct radiation, visibility, hazy days between 1993~2014. The results show that the concentrations of PM₁₀, SO₂ and NO₂ in Urumqi during the wintertime of 2013~2014 decline by 26.1%, 80.2% and 11.6% respectively compared to those in the wintertime of 2009~2011 which represent the concentrations before CTGE. The ratio of total water-soluble matter to PM_2.5 also decreases by 20.57%. The top three ions' concentrations in PM_2.5 are SO₄^2-, NH₄⁺ and NO₃^- before and after the CTGE. However, there is 50% decrease of the mass fractions of SO₄^2- and NH₄⁺ in PM_2.5 after the CTGE, and the mass fraction of NO₃^- in PM_2.5 remains unchanged. In the view of atmospheric physics, the total direct radiations during the wintertime in Urumqi increase after the CTGE and the value of 2013~2014 reaches up to the second peak for the past 23 years. There is a 5.7km increase for the wintertime visibility of 2013~2014 which is the maximum value since 1997. At the same time, there are 15days less for the wintertime hazy days of 2012~2013 compared to that of previous year which is a decrease of 50%. The results and analysis indicate that the CTGE for heating improved the atmospheric environment in Urumqi to a certain extent.