Insights into a historic severe haze event in Shanghai: synoptic situation, boundary layer and pollutants

Abstract

Abstract. A historic haze event, characterized by lengthy, large-scale and severe pollution, occurred in the Yangtze River Delta (YRD) of China from 1 to 10 December 2013. This haze event significantly influenced air quality throughout the region, especially in urban areas. Aerosol physical, chemical and optical properties were measured in Shanghai. Sometimes the 1 h average particle concentration (e.g., PM 2.5 ) exceeded 600 µg m −3 . Inorganic water-soluble ions in particles, trace gases and aerosol optical coefficients had a similar tendency to increase evidently from clear to hazy episodes. A combination of various factors contributed to the formation and evolution of the haze event, among which meteorological conditions, local anthropogenic emissions and pollutants are the major factors. High pressure system, calm surface wind and subsidence airflow were responsible for the decrease of planetary boundary layer (PBL) and the accumulation of pollutants. Atmospheric visibility correlated strongly with relative humidity (RH), particle number in size of 600-1400 nm other than particulate water-soluble species and particle mass (PM 2.5 ). The particle hygroscopicity plays an important role in atmospheric visibility reduction. The results are somewhat helpful to forecast and eliminate regional atmospheric pollution in China.

On the Relationship Between Aerosol and Boundary Layer Height in Summer in China Under Different Thermodynamic Conditions

“…Among others, the increases in aerosol concentrations were accompanied by high relative humidity (RH) conditions, where enhanced hygroscopic growth and multiphase reactions facilitated the increases in particle size and mass (Miao, Guo, Liu, Liu, Zhang, et al, ; Tie et al, ; Zhong et al, ). High‐pressure systems were revealed to significantly prevent the diffusion of atmospheric pollutants, causing severe haze pollution (Chen et al, ; Leng et al, ; Wu et al, ; Yang et al, ; Zhang et al, ). In addition, the dynamic and thermodynamic features of the PBL can be substantially modified by aerosols, which tends to stabilize or invigorate the PBL depending on the aerosol types or the altitudes where aerosol particles aloft reside (Barbaro et al, ; Talukdar et al, ; Wilcox et al, ).…”

“…This has been widely studied using the BLH estimates from lidar observations, radiosonde measurements, satellite remote sensing, and model simulation (Li et al, ; Miao et al, ; Pasch et al, ; Su et al, ; Tsaknakis et al, ; Wang et al, ). Previous studies involved in the interaction between aerosol and PBL in China were either limited to a specific region or limited time period (Du et al, ; Leng et al, ; Quan et al, ). This is partly due to the lack of national‐level high‐resolution observations available for the BLH estimates in China (Zhang et al, ).…”

Climatic Factors and Their Availability in Estimating Long‐Term Variations of Fine Particle Distributions Over East China

“…Great efforts have been devoted to investigating the mechanism of air pollution in China (Gao et al, ; Huang et al, ; Leng et al, ; Sun et al, ; Wang et al, ; Zhang et al, ). It is well known that increase of emissions is considered as the primary reason for the increase of polluted days in China (Chen & Wang, ).…”

Dual effects of the winter monsoon on haze‐fog variations in eastern China

“…Many persistent and severe haze‐fog events occurred in these two months. A long‐lasting episode of severe haze occurred in January 2013 over central and eastern China [ Wang et al , ; Zhang et al , ], a persistent haze episode occurred in Guanzhong basin from 16 to 25 December 2013 [ Bei et al , ], and some multiday haze episodes also occurred in the Yangtze River Delta in December 2013 [ Tang et al , ; Leng et al , ]. According to these studies, the subseasonal variations in haze‐fog are also influenced by the EAWM.…”