Quantitative Assessment Of The Impact Of Meteorology And Emissions On The Evolution Of Ozone Pollution In The Pearl River Delta

In recent years,air quality in the Pearl River Delta region has been substantially improved with the vigorous control measures and secientfice support.However,ambient ozone concentrations,influenced by the precurros emissions and meteorological conditions,in the PRD region still increasing.During 2006-2015,NOx emissions in the PRD region reduced by12153 tons,while VOC emissions steadily grew,whose impacts on air quality is still unclear.To deepen the air quality fine management in the PRD region and curb ozone growth,quantitative investigation into the impact of ozone precursor emission changes and meteorological variations on ozone pollution in PRD and indentifying the driving factors is the essential.In this study,by combining a detailed bottom-up emission inventory over the PRD region,the WRF-CMAQ(Weather Research and Forecasting Model and Community Multiscale Air Quality)model and observation data,we attributed the growth in PRD's ozone air quality during2006-2015 to the following factors:changes in meteorological conditions and emission changes.Results showed that 1)ozone concentrations presented a weaklike increasing trend during the period of 2006-2015 in the PRD region;2)The steadily growth in ozone concentrations in PRD during 2006-2015 was dominated by the local emission changes(7.58?g/m~3 for the maximum daily 8-hour average ozone and 9.16?g/m~3 for the 90%pentitle of maximum daily8-hour average ozone).On the contrary,meteorological variation dominated the annual fluctuation of ozone concentrations and suppressed the growth of peak ozone concentration(-7.45?g/m~3 for the 90%pentitle of maximum daily 8-hour average ozone).3)The local emissions have more positive effect on the ozone pollution in the downwind areas.The impact of emission changes on the ozone pollution in the NPRD is weaker than that on the PRD.4)the growth of ozone pollution in the PRD was mainly caused by the increase of VOC emissions,while it was mainly caused by the decrease of NOx emissions in the NPRD.