Co-effect assessment on regional air quality: A perspective of policies and measures with greenhouse gas reduction potential.

ABSTRACT

Clean air policies have achieved remarkable air quality improvement in China for the last decade. However, as more importance was attached to climate issues and further improvement of air quality, policies with greenhouse gas (GHG) reduction potential were supposed to play a significant role. Here, we designed a conventional legislation pathway scenario (CLP) and an enhanced greenhouse gas reduction scenario (EGR), to estimate the co-effects of policies effective in GHG reduction on air pollutant control and air quality improvement in the Yangtze River Delta (YRD) region from 2014 to 2020, adopting a measure-specific evaluation method and an integrated WRF-CAMx model simulation. Results showed that 1) With the implementation of enhanced measures with GHG reduction potential, emissions of SO2, NOx, PM2.5, PM10, VOCs and NH3 decreased by 16.4 %, 21.6 %, 18.6 %, 16.5 %, 23.9 % and 15.4 % in EGR scenario respectively, compared with CLP scenario. And the annual mean simulated concentrations of PM2.5, SO2 and NO2 of the YRD decreased by 11.2 %, 15.4 % and 20.6 %, respectively. 2) The average 8-h maxima (MDA8) concentration of O3 presented a slightly increasing trend under the impacts of measures with GHG reduction potential, which might be on account of the unbalanced control of NOx and VOCs, the two major precursors of O3. 3) Based on the source apportionment analysis, major partition of total ozone in the four receptors in YRD was from regional transportation, rather than local formation. And the major sectors contributing to ozone were industry and transportation sector. This study quantitatively assessed the co-benefits of GHG-control-effective policies and specific measures on air quality improvement, which would help to provide implications for future policy-making to achieve air pollution and climate change co-control.