Continuous aggravated surface O_(3) over North China Plain(NCP)has attracted widely public concern.Herein,we evaluated the effects of changes in aerosols,precursor emissions,and meteorology on O_(3) in summer(June)of ...Continuous aggravated surface O_(3) over North China Plain(NCP)has attracted widely public concern.Herein,we evaluated the effects of changes in aerosols,precursor emissions,and meteorology on O_(3) in summer(June)of 2015–2019 over NCP via 8 scenarios with WRF-Chem model.The simulated mean MDA8 O_(3) in urban areas of 13 major cities in NCP increased by 17.1%∼34.8%,which matched well with the observations(10.8%∼33.1%).Meanwhile,the model could faithfully reproduce the changes in aerosol loads,precursors,and meteorological conditions.A relatively-even O_(3) increase(+1.2%∼+3.9%for 24-h O_(3) and+1.0%∼+3.8%for MDA8 O_(3))was induced by PM_(2.5) dropping,which was consistent with the geographic distribution of regional PM_(2.5) reduction.Meanwhile,the NO_(2) reduction coupled with a nearconstant VOCs led to the elevated VOCs/NOx ratios,and then caused O_(3) rising in the areas under VOCs-limited regimes.Therein,the pronounced increases occurred in Handan,Xingtai,Shijiazhuang,Tangshan,and Langfang(+10.7%∼+13.6%for 24-h O_(3) and+10.2%∼+12.2%forMDA8 O_(3));while the increases in other citieswere 5.7%∼10.5%for 24-h O_(3) and 4.9%∼9.2%for MDA8 O_(3).Besides,the meteorological fluctuations brought about the more noticeable O_(3) increases in northern parts(+12.5%∼+13.5%for 24-h O_(3) and+11.2%∼+12.4%for MDA8 O_(3))than those in southern and central parts(+3.2%∼+9.3%for 24-h O_(3) and+3.7%∼+8.8%for MDA8 O_(3)).The sum of the impacts of the three drivers reached 16.7%∼21.9%,which were comparable to the changes of the observed O_(3).Therefore,exploring reasonable emissionsreduction strategies is essential for the ozone pollution mitigation over this region.展开更多
核电厂事故时放射性核素大气扩散特征是核电厂环境影响评价中重点关注问题。目前核电厂环境影响评价中采用单一气象场驱动进行预测分析不足以真实反映放射性核素事故时大气扩散特征。以某核电厂厂址为研究对象,利用核事故短期大气弥散...核电厂事故时放射性核素大气扩散特征是核电厂环境影响评价中重点关注问题。目前核电厂环境影响评价中采用单一气象场驱动进行预测分析不足以真实反映放射性核素事故时大气扩散特征。以某核电厂厂址为研究对象,利用核事故短期大气弥散因子计算软件PAVAN(Potential Accident Consequence Assessments at Nuclear Power Plants)模拟不同气象场驱动情景下核电厂事故时放射性核素大气扩散特征,以确定气象场驱动差异对事故时放射性核素大气扩散的影响。结果表明:多年气象场驱动条件下非居住区边界和规划限制区边界的短期大气弥散因子年均值最大值分别为单一气象场驱动条件的1.05和1.04倍,均出现在S方位。不同情景下非居住区边界大气弥散因子年均值最大值在CASE2和CASE4情景下相同,但出现方位不同,分别出现在S和NE方位;CASE4情景下大气弥散因子年均值变异程度大于CASE2情景;非居住区边界30 d内CASE2、CASE3和CASE4情景下短期大气弥散因子的最大值分布范围依次为(6.01E-5~7.78E-5)、(5.72E-5~7.79E-5)和(6.29E-5~7.79E-5)s/m3。不同情景下规划限制区边界大气弥散因子最大值从大到小依次为CASE2>CASE4>CASE1>CASE3,依次出现在S、NE、S、NE方位;规划限制区边界30 d内CASE2、CASE3和CASE4情景下短期大气弥散因子的最大值分布范围依次为(1.17E-5~1.95E-5)、(1.09E-5~1.98E-5)和(1.24E-5~1.98E-5)s/m3。展开更多
基金supported by the National Natural Science Foundation of China(Nos.51978010,52022005).
文摘Continuous aggravated surface O_(3) over North China Plain(NCP)has attracted widely public concern.Herein,we evaluated the effects of changes in aerosols,precursor emissions,and meteorology on O_(3) in summer(June)of 2015–2019 over NCP via 8 scenarios with WRF-Chem model.The simulated mean MDA8 O_(3) in urban areas of 13 major cities in NCP increased by 17.1%∼34.8%,which matched well with the observations(10.8%∼33.1%).Meanwhile,the model could faithfully reproduce the changes in aerosol loads,precursors,and meteorological conditions.A relatively-even O_(3) increase(+1.2%∼+3.9%for 24-h O_(3) and+1.0%∼+3.8%for MDA8 O_(3))was induced by PM_(2.5) dropping,which was consistent with the geographic distribution of regional PM_(2.5) reduction.Meanwhile,the NO_(2) reduction coupled with a nearconstant VOCs led to the elevated VOCs/NOx ratios,and then caused O_(3) rising in the areas under VOCs-limited regimes.Therein,the pronounced increases occurred in Handan,Xingtai,Shijiazhuang,Tangshan,and Langfang(+10.7%∼+13.6%for 24-h O_(3) and+10.2%∼+12.2%forMDA8 O_(3));while the increases in other citieswere 5.7%∼10.5%for 24-h O_(3) and 4.9%∼9.2%for MDA8 O_(3).Besides,the meteorological fluctuations brought about the more noticeable O_(3) increases in northern parts(+12.5%∼+13.5%for 24-h O_(3) and+11.2%∼+12.4%for MDA8 O_(3))than those in southern and central parts(+3.2%∼+9.3%for 24-h O_(3) and+3.7%∼+8.8%for MDA8 O_(3)).The sum of the impacts of the three drivers reached 16.7%∼21.9%,which were comparable to the changes of the observed O_(3).Therefore,exploring reasonable emissionsreduction strategies is essential for the ozone pollution mitigation over this region.
文摘核电厂事故时放射性核素大气扩散特征是核电厂环境影响评价中重点关注问题。目前核电厂环境影响评价中采用单一气象场驱动进行预测分析不足以真实反映放射性核素事故时大气扩散特征。以某核电厂厂址为研究对象,利用核事故短期大气弥散因子计算软件PAVAN(Potential Accident Consequence Assessments at Nuclear Power Plants)模拟不同气象场驱动情景下核电厂事故时放射性核素大气扩散特征,以确定气象场驱动差异对事故时放射性核素大气扩散的影响。结果表明:多年气象场驱动条件下非居住区边界和规划限制区边界的短期大气弥散因子年均值最大值分别为单一气象场驱动条件的1.05和1.04倍,均出现在S方位。不同情景下非居住区边界大气弥散因子年均值最大值在CASE2和CASE4情景下相同,但出现方位不同,分别出现在S和NE方位;CASE4情景下大气弥散因子年均值变异程度大于CASE2情景;非居住区边界30 d内CASE2、CASE3和CASE4情景下短期大气弥散因子的最大值分布范围依次为(6.01E-5~7.78E-5)、(5.72E-5~7.79E-5)和(6.29E-5~7.79E-5)s/m3。不同情景下规划限制区边界大气弥散因子最大值从大到小依次为CASE2>CASE4>CASE1>CASE3,依次出现在S、NE、S、NE方位;规划限制区边界30 d内CASE2、CASE3和CASE4情景下短期大气弥散因子的最大值分布范围依次为(1.17E-5~1.95E-5)、(1.09E-5~1.98E-5)和(1.24E-5~1.98E-5)s/m3。
