Reduction in Near‐Surface Wind Speeds With Increasing CO<sub>2</sub> May Worsen Winter Air Quality in the Indo‐Gangetic Plain
Fabien Paulot, Vaishali Naïk, Larry W. Horowitz
Abstract
Abstract We analyze the relationship between fine particulate matter (PM 2.5 ) and meteorology in winter in the Indo‐Gangetic Plain (IGP). We find that the concentration of PM 2.5 exhibits similar increase with decreasing surface wind speed in 15 out of 18 cities considered. Using this observed relationship, we estimate that the reduction of surface wind speed with increasing CO 2 simulated by models participating in the Coupled Model Intercomparison Project Phase 6 will result in higher average wintertime PM 2.5 concentrations (1% per degree K of global warming) and more frequent high‐pollution events. This observation‐based estimate is qualitatively consistent with the simulated response of black carbon to global warming inferred from the AerChemMIP ssp370SST and ssp370pdSST experiments. We hypothesize that a reduction in the frequency and intensity of western disturbances with increasing CO 2 may contribute to the reduction in the surface wind in the IGP.