Rapid formation and evolution of an extreme haze episode in Northern China during winter 2015

Citations Over TimeTop 1% of 2016 papers

Abstract

We investigate the rapid formation and evolutionary mechanisms of an extremely severe and persistent haze episode that occurred in northern China during winter 2015 using comprehensive ground and vertical measurements, along with receptor and dispersion model analysis. Our results indicate that the life cycle of a severe winter haze episode typically consists of four stages: (1) rapid formation initiated by sudden changes in meteorological parameters and synchronous increases in most aerosol species, (2) persistent evolution with relatively constant variations in secondary inorganic aerosols and secondary organic aerosols, (3) further evolution associated with fog processing and significantly enhanced sulfate levels, and (4) clearing due to dry, cold north-northwesterly winds. Aerosol composition showed substantial changes during the formation and evolution of the haze episode but was generally dominated by regional secondary aerosols (53-67%). Our results demonstrate the important role of regional transport, largely from the southwest but also from the east, and of coal combustion emissions for winter haze formation in Beijing. Also, we observed an important downward mixing pathway during the severe haze in 2015 that can lead to rapid increases in certain aerosol species.

Related Papers

• → Secondary Formation of Sulfate and Nitrate during a Haze Episode in Megacity Beijing, China(2015)88 cited
• → Identification of chemical compositions and sources of atmospheric aerosols in Xi'an, inland China during two types of haze events(2016)59 cited
• The Effects of Dust Haze Weather on Human Health(2008)
• Analysis of Mist and Haze Weather in Fushun City from 2004 to 2013(2014)
• A Study on Long-term Change of Haze Days Based on Wavelet Transform and M-K Test(2012)