大连市夏季近地面臭氧污染数值模拟和控制对策研究

Modeling of Summertime Ground-Level Ozone Pollution and Its Control Strategies in Dalian

通过区域空气质量模型CAMx对大连市2015年8月近地面臭氧(O_3)污染进行模拟,探讨了O_3及其生成前体物(NOx和VOCs)的来源,O_3生成控制区,并根据敏感性分析结果对前体物排放的控制效果进行了定量评估。结果表明:本地NOx排放对大连地区的NOx浓度贡献占90%以上,本地VOCs排放对大连地区的VOCs浓度贡献占80%以上,而本地NOx和VOCs排放对大连地区O_3浓度贡献仅占29%;大连市整体上为VOCs控制区,控制VOCs能有效降低O_3污染,还能有效削减O_3的峰值浓度;通过敏感性分析结果计算得出,削减大连本地工业源VOCs和民用源VOCs能够有效降低大连地区O_3浓度,削减10%的工业源VOCs能使市区O_3平均浓度降低2%左右,削减10%的民用源VOCs能使大连市区平均O_3浓度降低1%左右。建议NOx与VOCs削减比例为1∶2,对大连市O_3和PM2.5污染进行协同控制。

The simulations of a summertime ground-level ozone pollution episode in August 2015 in Dalian city are performed using regional air quality model（CAMx） in this study.The source apportionment of ozone and its precursors（NOxand VOCs） is analyzed,the ozone control zones in Dalian are distinguished,and the effects of reducing ozone precursors＇ emissions are evaluated via sensitivity analysis.The results show that local NOxand VOCs emissions contribute more than 90% NOx concentrations and more than 80% VOCs concentrations in Dalian,respectively.However,only 29% O3 concentrations are contributed by the local emissions.The ozone pollution in Dalian is in the VOCs control zone,indicating that reducing VOCs emissions may bring down both 8 h ozone and peak 1 h ozone concentrations.Based on the relationships between ozone concentrations and its precursor＇s emissions built by sensitivity coefficients,reducing 10% VOCs emissions in local industrial sector and residential sector may bring down ozone concentrations by 2% and 1% in Dalian,respectively.The results also suggest an optimized NOxand VOCs reduction ratio of 1∶2 to alleviate both O3 and PM2.5 pollutions simultaneously.