保定市夏季臭氧生成敏感性及前体物减排方案

Ozone sensitivity and precursor emission reduction scheme in Baoding City in summer

基于2015~2019年7月保定市常规污染物和气象观测数据,研究分析了保定市夏季O_(3)污染特征及其与气象因子的响应关系;结合WRF-CMAQ模式和EKMA曲线法研究确定了保定地区O_(3)敏感性特征及前体物(NOx与VOCs)的减排方案.结果表明,2015~2019年7月MDA8O_(3)平均浓度在138~179μg/m^(3)之间;相较2015年,2019年7月O_(3)日最大8h平均浓度(MDA8O_(3))平均浓度上升了10.5%;主要气象因子中,O_(3)与温度呈正相关,与相对湿度呈负相关,且在O_(3)超标日时,相关性更强,分别为0.81和-0.70;在O_(3)超标日下,当风向为西风、西南风、南风和东南风时,O_(3)小时浓度更容易出现高值;保定市主城区、南部及东部区县属于VOCs控制区,西部和北部区县属于VOCs和NOx协同控制区.对于以城区为代表的VOCs控制区,建议优先减排VOCs;对于西部和北部郊县建议NOx:VOCs减排比例大于1.

Based on the datasets of air pollutant concentrations and meteorological conditions of Baoding from 2015 to July 2019,the relationship between O_(3) characteristics and meteorological factors in summer season was analyzed.The O_(3) sensitivity and the reduction scheme of precursors(NOx and VOCs)emissions was determined combining WRF-CMAQ simulations and EKMA curve.Results indicated that monthly average concentrations of MDA8O_(3) in July from 2015 to 2019 ranged from 138 to 179μg/m^(3).Compared with 2015,the average concentration of MDA8O_(3) in July 2019 increased by 10.5%.Among the major meteorological factors,the ozone concentration was positively correlated with temperature(R=0.81 on nonattainment days)and negatively correlated with relative humidity(R=-0.70 on nonattainment days).And higher concentration of O_(3) mainly occurred accompanied with west wind,southwest wind,south wind and southeast wind.Ozone formation was in the strong VOCs-limited regime in the main urban,southern and eastern suburban of Baoding city,however,it was in the NOx and VOCs transition regime in the western and northern suburban.Thus,it was suggested that the reduction of VOCs emissions should be priority considered in VOCs-limited regime regions.As for the western and northern suburban,the reduction ratio of NOx:VOCs should be larger than 1.