空气质量保障措施的量化评估——以杭州G20峰会为例

Quantitative assessment of air quality guarantee measures:take G20 Summit in Hangzhou as an example

选择杭州G20峰会保障措施实施期间的2016年8月24日—9月6日及其前后各14 d,分别确定为保障措施实施期间、实施前期与实施后期,对保障区域内主要大气污染物浓度变化进行分析,利用WRF/SMOKE/CMAQ模型对4类污染源(工业源、电厂源、扬尘源和道路移动源)设置6种减排情景,模拟计算并分析PM2.5和O3浓度变化,以评估强化环保措施对空气质量改善的成效。结果表明:1)研究期间杭州市各项污染物浓度呈起伏波动状,保障措施实施期间大部分时段污染物浓度峰谷差值明显比前期和后期小;NO2平均浓度表现为保障措施实施后期>前期>期间,保障措施对NO2减排效果显著;O3浓度表现为保障措施实施期间远高于前期与后期。2)与2015年同期相比,2016年保障措施实施期间,NO2、SO2、PM2.5、CO和PM10浓度在核心区和严控区下降,降幅表现为核心区>严控区>管控区;2016年核心区NO2、PM2.5、CO和PM10浓度均低于2017年;2016年相较2015年和2017年同期空气质量较好,不同力度的管控措施对空气质量的影响有差异,O3浓度变化规律与其他污染物浓度变化呈负相关。3)模拟对4类污染源都实施保障措施,核心区与严控区较强的管控措施执行力度使PM2.5浓度下降,O3浓度升高。4)模拟结果显示,对工业源做管控措施,能有效降低核心区与严控区PM2.5和O3排放;对电厂源或扬尘源实行管控措施只能略微抑制核心区与管控区PM2.5和O3排放;对道路移动源做减排措施,核心区与严控区O3浓度升幅较大。

From August 24 to September 6,2016,and 14 days before and after the implementation period of the guarantee measures of G20 Summit in Hangzhou were selected as the earlier and the later stages of the implementation of the guarantee measures,and the concentration changes of the main air pollutants in the guarantee area were analyzed.The WRF/SMOKE/CMAQ model was used to set up six scenarios of emission reduction for four types of pollution sources(industrial source,power plant source,dust source and road mobile source),and PM2.5 and O3 concentration changes were analyzed to evaluate the effect of strengthening environmental protection measures on air quality improvement.The results showed that:1)During the whole research period,the concentrations of pollutants in Hangzhou were in the form of a wave,and the difference between the peak and valley concentrations of pollutants in most periods of the implementation of the guarantee measures was significantly smaller than that in the earlier and later periods;the average concentration of NO2 was in the later period>the earlier period>the period of the implementation of the guarantee measures,and the effect of the guarantee measures on the emission reduction of NO2 was significant;the concentration of O3 in the period of the implementation of the guarantee measures was much higher than that in the earlier and later periods.2)Compared with the same period in 2015,the concentrations of NO2,SO2,PM2.5,CO and PM10 in the core area and strict control area decreased during the implementation of the measures in 2016,with a decrease of core area>strict control area>control area;the concentrations of NO2,PM2.5,CO and PM10 in the core area in 2016 were lower than those in 2017;the air quality in 2016 was better than that in 2015 and 2017;the impact of different control measures on air quality was different,and the variation of O3 concentration was negatively correlated with the variation of other pollutants.3)Four types of pollution sources were simulated to implement guarantee measures;the strong implementation of control measures in the core area and strict control area made PM2.5 concentration decrease and O3 concentration increase.4)The simulation results showed that the control measures for industrial sources could effectively reduce PM2.5 and O3 emissions in the core area and strict control area;the control measures for power plant sources or dust sources could only slightly inhibit PM2.5 and O3 emissions in the core area and control area;the emission reduction measures for road mobile sources could significantly increase O3 concentration in the core area and strict control area.