基于转置EKMA曲线的湖南省臭氧生成敏感性分析

Study of Ozone Formation Sensitivity in Hunan Province Based on the Transformed-EKMA Curve Approach

基于湖南省2015—2020年夏秋季的污染物及气象观测数据,分析了臭氧(O_(3))污染的时空特征和生成敏感性。湖南省中部和北部的O_(3)污染较为严重,且主要发生在9月,午后O_(3)峰值常与早高峰的NO_(2)浓度有较高的相关性。采用转置EKMA曲线方法探究了O_(3)在NO_(2)维度和VOCs反应活性维度下的生成敏感性。在NO_(2)维度下,NO_(2)控制区和NO_(2)-VOCs过渡区的NO_(2)质量浓度为7~13μg/m^(3),NO_(2)-VOCs过渡区和VOCs控制区的NO_(2)质量浓度为15~17μg/m^(3)。在VOCs反应活性维度下,当NO_(2)质量浓度大于10μg/m^(3)时,VOCs反应活性越高,O_(3)浓度越高。在高VOCs反应活性(30℃或以上)时,NO_(2)浓度每降低1μg/m^(3),各区域的O_(3)质量浓度能降低约8~9μg/m^(3)。结合NO_(2)和VOCs反应活性2个维度,得出湖南省午后O_(3)生成以NO_(2)控制区和NO_(2)-VOCs过渡区为主,在晴天干燥和高温条件下,减排NO_(2)可有效降低O_(3)浓度。转置EKMA曲线方法为缺少长期VOCs观测的区域提供了研究O_(3)生成敏感性的新思路。

The temporal and spatial variation characteristics of ozone(O_(3))pollution and the sensitivity of O_(3) formation were investigated,based on the air quality and meteorology observation in summer and autumn from 2015 to 2020 in Hunan Province.O_(3) pollution mainly emerged in the central and northern parts of Hunan Province and usually occurred in September.The peak concentration of O_(3) in the afternoon was highly correlated with the NO_(2) concentration in the morning.With the transformed-EKMA curve approach,the sensitivity of O_(3) formation to both NO_(2) concentration and the total reactivity of VOCs were analyzed.In terms of NO_(2) concentration,the dividing NO_(2) concentration of the NO_(2)-limited and the NO_(2)-VOCs-transitional regime,the NO_(2)-VOCs-transitional and the VOCs-limited regime were each located between 7-13μg/m^(3) and 15-17μg/m^(3).In terms of the total reactivity of VOCs,the higher the total reactivity of VOCs,the higher the O_(3) concentration when the NO_(2) concentration was above 10μg/m^(3).When the temperature was above 30℃,the O_(3) concentration would be diminished by 8 to 9μg/m^(3) as the NO_(2) concentration decreased by 1μg/m^(3).In conclusion,the O_(3) formation at 14:00 in summer and autumn was mainly under the NO_(2)-limited or the NO_(2)-VOCs-transitional regime,suggesting that the emission reduction of NO_(2) could effectively control O_(3) pollution on high temperature days in Hunan Province.For regions lacking long-term VOCs observation,a new insight into the analysis of the O_(3) formation sensitivity was provided.