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

Based on the datasets of air pollutant concentrations and meteorological conditions of Baoding from 2015 to July 2019, the relationship between O3 characteristics and meteorological factors in summer season was analyzed. The O3 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 MDA8O3 in July from 2015 to 2019 ranged from 138 to 179µg/m3. Compared with 2015, the average concentration of MDA8O3 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 O3 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. © 2023 Chinese Society for Environmental Sciences. All rights reserved.