Dust-wind interactions can intensify aerosol pollution over eastern China

Yang Yang,Sijia Lou,Lynn M. Russell,Ying Liu,Jianping Guo,Hong Liao,Steven J. Ghan,Balwinder Singh

doi:10.1038/ncomms15333

Abstract

Eastern China has experienced severe and persistent winter haze episodes in recent years due to intensification of aerosol pollution. In addition to anthropogenic emissions, the winter aerosol pollution over eastern China is associated with unusual meteorological conditions, including weaker wind speeds. Here we show, based on model simulations, that during years with decreased wind speed, large decreases in dust emissions (29%) moderate the wintertime land–sea surface air temperature difference and further decrease winds by −0.06 (±0.05) m s−1 averaged over eastern China. The dust-induced lower winds enhance stagnation of air and account for about 13% of increasing aerosol concentrations over eastern China. Although recent increases in anthropogenic emissions are the main factor causing haze over eastern China, we conclude that natural emissions also exert a significant influence on the increases in wintertime aerosol concentrations, with important implications that need to be taken into account by air quality studies.

Highlights

Eastern China has experienced severe and persistent winter haze episodes in recent years due to intensification of aerosol pollution
Recent increases in anthropogenic emissions are the main factor causing haze over eastern China, we conclude that natural emissions exert a significant influence on the increases in wintertime aerosol concentrations, with important implications that need to be taken into account by air quality studies
We suggest that dust intensifies wintertime anthropogenic aerosol pollution over eastern China by reducing wind speed

Summary

Introduction

Eastern China has experienced severe and persistent winter haze episodes in recent years due to intensification of aerosol pollution. In addition to anthropogenic emissions, the winter aerosol pollution over eastern China is associated with unusual meteorological conditions, including weaker wind speeds. Recent increases in anthropogenic emissions are the main factor causing haze over eastern China, we conclude that natural emissions exert a significant influence on the increases in wintertime aerosol concentrations, with important implications that need to be taken into account by air quality studies. Interannual variations in dust emissions are large[16] and may influence anthropogenic aerosol pollution over eastern China through changing meteorological fields. Few previous studies have examined the effects of interannual variability of dust on meteorological fields, especially during winter when aerosol pollution is the most severe over eastern China

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