Quantitative Assessment Of Air Quality Assurance Measures

Through literature and research,collected air quality assurance measures and action plans implemented during the 2016 Hangzhou G20 Summit.Choose the period of implementation of the safeguard measures（August 24 to September 6,2016）and the 14 days before and after it are determined as the pre-implementation of the safeguard measures（August 10 to August 23）and the later period（September 7 to September 20）.Use the time series method in statistics to analyze the changes in the concentrations of PM_2.5,PM₁₀,O₃,CO,SO₂,NO₂ 6 pollutants in the early,during and after the implementation of safeguard measures,and compare them with the pollutants in the same period of 2015 and the same period of 2017.The impact of the implementation of air quality assurance measures and action plans on the air quality in the Hangzhou G20 Summit was discussed,especially the contribution to the air quality assurance of the G20 Summit.Based on the air quality assurance measures and plans during the G20 summit,different emission reduction scenarios were set,and the WRF/SMOKE/CMAQ air quality model system was used to carry out eight types of pollution sources such as power plant,industry,on road mobile,dust,and ships during the implementation of the G20 summit safeguard.The simulation of the seven kinds of pollutants simulated the change of the concentration of the main pollutants under the six scenarios of no emission reduction measures,individual pollution sources（power plant,industry,on road mobile,dust）with emission reduction measures and no emission reduction measures.The results indicated:（1）During the whole research period,the evolution of pollutant concentration in Hangzhou showed a wave like trend.During the implementation of safeguard measures,the difference between peak and valley of pollutant concentration in most periods was significantly smaller than that in the earlier and later periods,which reflected the effect of the implementation of the measures.During the period,August 29,September 3 and September 4,there were three significant concentration surge phenomena,which was closely related to the weather background at that time.Compared with the average concentrations of various pollutants in the early,middle and later stages of the implementation of the measures,concentration of NO₂ is the later period>the earlier period>the period,and the emission reduction effect of the safeguard measures is very obvious.Concentrations of PM_2.5,SO₂and CO are the later period>the earlier period>the period,concentration of PM₁₀ is the period>the later period>the earlier period.Concentration of O₃ is far beyond the earlier period and the later period.（2）During the implementation of the measures,the concentrations of major pollutants in Hangzhou were significantly lower than in the same period in 2015,and the concentrations of NO₂ and CO were lower than in the same period in 2017.During the guarantee period,the implementation of control measures and emission reduction programs has effectively improved air quality.（3）During the implementation period,the concentration of PM_2.5,NO₂ and SO₂ in the core area is slightly lower than that in the strict control area,the air quality in the core area is better than that in the strict control area.The decline of most pollutants from 2015 to 2016 showed the characteristics of core area>strict control area>control area.The concentrations of PM_2.5,PM₁₀,NO₂,and CO in the core area increased in 2017 compared to 2016,indicating that different levels of control measures have different effects on air quality.（4）According to the analysis of PM_2.5 simulation data,when the four pollution sources（industrial source,power plant source,dust source and on road mobile source）are all implemented with safeguard measures,the emission reduction schemes issued by the government effectively control the PM_2.5 emission,providing guarantee for improving air quality.Strict control measures in core and strict control areas play a more significant role in suppressing PM_2.5 emissions;industrial pollution source control measures can effectively reduce PM_2.5,implementing control measures on power plant sources or dust sources can only suppress PM_2.5emissions in core areas and control areas.（5）Analysis of O₃ simulation data is available.When no emission reduction measures are implemented,O₃ is high in the core area,followed by strict control area,O₃is the lowest in the control area,PM_2.5concentration high value area corresponds to O₃ concentration low value area.when all four pollution sources are used for emission reduction measures,the stronger the implementation of control measures,O₃will increase.The emission reduction of industrial sources will inhibit the core areas of Zhejiang Province and the northeast of strictly controlled areas O₃generation.Power plant emission reductions can only slightly suppress O₃emissions in core and strictly controlled areas,and emission reduction measures for road moving sources,O₃ in core and strictly controlled areas have increased significantly.