2019年7月石家庄市O3生成敏感性及控制策略解析

基于石家庄市2019年7月近地面污染物和气象观测数据，分析夏季O₃污染状况及其影响因素；结合WRF-CMAQ模式和O₃浓度等值线（EKMA曲线）,探究不同区域O₃-VOCs-NO_x的非线性响应关系，旨在探究最佳的前体物减排方案.结果表明，观测期间，石家庄市市区MDA8 O₃超标率高达70.9%.污染天期间，伴随着高温、低湿、小风，且以南风和东南风为主.石家庄市市区属于VOCs控制区，郊县为NO_x和VOCs协同控制区.在臭氧污染时段，市区在仅削减NO_x排放，且削减比例超过50%时，持续减排NO_x使得O₃浓度呈逐渐下降趋势.在非臭氧日时段，市区在VOCs和NO_x的削减比例大于1倍时，O₃浓度才不会出现反弹.对于市区应考虑以仅削减VOCs为先；对于郊县区域而言，不同的NO_x和VOCs削减比例下，O₃浓度均会下降...

Ozone Sensitivity Analysis and Control Strategy in Shijiazhuang City in July 2019

The pollution characteristics of surface ozone and its response to meteorological factors were studied based on monitoring in July 2019 in Shijiazhuang City, China. Furthermore, the WRF-CMAQ model coupled with O₃ isopleths (EKMA curves) were applied to explore the non-linear response relationship of O₃ to precursors VOCs and NO_x, aiming to identify a suitable precursor control strategy. The results showed that the days with the maximum daily 8-hour average ozone concentration (MDA8 O₃) exceeded the standard by 70.9%. The nonattainment days were usually accompanied by higher temperature, lower relative humidity, and low winds, and the south and southeast winds occurred frequently. The O₃ formation was in the strong VOC-limited regime in the urban area of Shijiazhuang, whereas it was in the NO_x and VOCs transition regime in suburban areas. As for the urban area, under the condition of single NO_x emission reduction, O₃ pollution improved when continuous NO_x emission reduction was higher than 50% during the nonattainment days. By contrast, during the non-polluted days, O₃ concentrations would not rebound when the reduction ratio of NO_x and VOCs was higher than 1. In conclusion, VOCs reduction should be the priority for emission reduction plans in urban areas, whereas all different NO_x and VOCs ratios led to a decline in O₃ concentration in the suburban areas, and a VOCs:NO_x of 1:2 was recommended.