Spatiotemporal characteristics of ozone pollution and policy implications in Northeast China

Özet

The ground-level ozone (O3) pollution has become an emerging air quality issue in China. To effectively mitigateozone pollution in Northeast China (NEC), this study focuses on its characteristics based on the surface ozone,meteorological data, and Ozone Monitoring Instrument (OMI) satellite data. Statistical methods are applied toanalyze the effects of meteorology on O3pollution. The results show that the area and annual averaged max-imum 8-h average O3concentrations rose from 81.3 to 87.4μg/m3during 2015–2018 and the nonattainmentdays kept increasing. The ground-observed O3concentrations and OMI ozone vertical column densities (VCDs)displayed the pattern of highs in the southwest and lows the northeast of the NEC region with the exceedanceareas mainly located over the Liaoning and Jilin provinces in spring and summer. The long-term series of O3,HCHO and NO2VCDs averaged over NEC all exhibited annual upward trends. Indicated by the OMI HCHO/NO2ratio, the seasonal and spatial O3-VOCs-NOxsensitivities in NEC provide the control measure guidance forgovernment agencies. Also the ozone control measure needs to consider the biogenic emissions along with theanthropogenic VOCs emissions due to the vast forest areas and large-scale agricultural production in NEC. Theozone pollution episodes in NEC were correlated with weather conditions of high temperature, low relativehumidity, long sunshine duration and southwesterly wind in summer and the impact of the East Asia summermonsoon cannot be ignored. Future investigation into VOCs’measurements and emission inventories are muchneeded for ozone pollution control in NEC.