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On the influence of atmospheric super-saturation layer on China's heavy haze-fog events
https://orcid.org/0000-0002-9427-2407
AbstractWith the background of global change, the air quality in Earth's atmosphere has significantly decreased. The North China Plain (NCP), Yangtze River Delta (YRD), Pearl River Delta (PRD) and Si-Chuan Basin (SCB) are the major areas suffering the decreasing air quality and frequent pollution events in recent years. Studying the effect of meteorological conditions on the concentration of pollution aerosols in these pollution sensitive regions is a hot focus now. This paper analyses the characteristics of atmospheric super-saturation and the corresponding H_PMLs (height of supersaturated pollution mixing layer), investigating their contribution to the frequently-seen heavy haze-fog weather. The results suggest that: (1) in the above-mentioned pollution sensitive regions in China, super-saturated layers repeatedly appear in the low altitude and the peak value of supersaturation S can reach 6–10%, which makes pollution particles into the wet adiabatic uplift process in the stable-static atmosphere. After low-level atmosphere reaches the super-saturation state below the H_PMLs, meteorological condition contributes to humidification and condensation of pollution particles. (2) Caculation of condensation function Fc, one of PLAM sensetive parameter, indicates that super-saturation state helps promote condensation, beneficial to the formation of Condensational Kink (CK) in the pollution sensitive areas. This favors the formation of new aerosol particles and intensities the cumulative growth of aerosol concentration. (3) By calculating the convective inhibition energy on average │CIN│ > 1.0 × 104 J kg−1, we found the value is about 100 times higher than the stable critical value. The uplifting diffusion of the particles is inhibited by the ambient airflow. So, this is the important reason for the aggravation and persistence of aerosol pollutants in local areas. (4) H_PMLs is negatively correlated to the pollution meteorological condition index PLAM which can describe the change of PM2.5 concentration. The lower the H_PMLs is, the higher the PLAM becomes, and the more conductive the air condition is to aggravation of pollutant aerosol concentration.
Graphical abstractSchematic diagram of 3-D model for low-level super-saturation layer (H_SSL) and pollution mixing layer (H_PMLs) in the pollution hotspots (NCP, YRD and PRD and SCB) in China. Light blue scarping down to the bottom of the vertical plane (B) is iso-θe surface for air adiabatic uplift; on the upper left corner of B-plane is the tephigram.
HighlightsImpact of the atmospheric super-saturation layer on heavy haze-fog pollution in China.Super-saturation state helps forming Condensational Kink (CK) in the polluted areas.Super-saturation below the height of pollution mixing layer favors the humidification of particles.Highly intensified convective inhibition of ambient atmosphere is favorable for heavy haze-fog.A feedback mechanism of micro-scale pollution processes to large-scale processes is an important reason.
On the influence of atmospheric super-saturation layer on China's heavy haze-fog events
https://orcid.org/0000-0002-9427-2407
AbstractWith the background of global change, the air quality in Earth's atmosphere has significantly decreased. The North China Plain (NCP), Yangtze River Delta (YRD), Pearl River Delta (PRD) and Si-Chuan Basin (SCB) are the major areas suffering the decreasing air quality and frequent pollution events in recent years. Studying the effect of meteorological conditions on the concentration of pollution aerosols in these pollution sensitive regions is a hot focus now. This paper analyses the characteristics of atmospheric super-saturation and the corresponding H_PMLs (height of supersaturated pollution mixing layer), investigating their contribution to the frequently-seen heavy haze-fog weather. The results suggest that: (1) in the above-mentioned pollution sensitive regions in China, super-saturated layers repeatedly appear in the low altitude and the peak value of supersaturation S can reach 6–10%, which makes pollution particles into the wet adiabatic uplift process in the stable-static atmosphere. After low-level atmosphere reaches the super-saturation state below the H_PMLs, meteorological condition contributes to humidification and condensation of pollution particles. (2) Caculation of condensation function Fc, one of PLAM sensetive parameter, indicates that super-saturation state helps promote condensation, beneficial to the formation of Condensational Kink (CK) in the pollution sensitive areas. This favors the formation of new aerosol particles and intensities the cumulative growth of aerosol concentration. (3) By calculating the convective inhibition energy on average │CIN│ > 1.0 × 104 J kg−1, we found the value is about 100 times higher than the stable critical value. The uplifting diffusion of the particles is inhibited by the ambient airflow. So, this is the important reason for the aggravation and persistence of aerosol pollutants in local areas. (4) H_PMLs is negatively correlated to the pollution meteorological condition index PLAM which can describe the change of PM2.5 concentration. The lower the H_PMLs is, the higher the PLAM becomes, and the more conductive the air condition is to aggravation of pollutant aerosol concentration.
Graphical abstractSchematic diagram of 3-D model for low-level super-saturation layer (H_SSL) and pollution mixing layer (H_PMLs) in the pollution hotspots (NCP, YRD and PRD and SCB) in China. Light blue scarping down to the bottom of the vertical plane (B) is iso-θe surface for air adiabatic uplift; on the upper left corner of B-plane is the tephigram.
HighlightsImpact of the atmospheric super-saturation layer on heavy haze-fog pollution in China.Super-saturation state helps forming Condensational Kink (CK) in the polluted areas.Super-saturation below the height of pollution mixing layer favors the humidification of particles.Highly intensified convective inhibition of ambient atmosphere is favorable for heavy haze-fog.A feedback mechanism of micro-scale pollution processes to large-scale processes is an important reason.
On the influence of atmospheric super-saturation layer on China's heavy haze-fog events
https://orcid.org/0000-0002-9427-2407
AbstractWith the background of global change, the air quality in Earth's atmosphere has significantly decreased. The North China Plain (NCP), Yangtze River Delta (YRD), Pearl River Delta (PRD) and Si-Chuan Basin (SCB) are the major areas suffering the decreasing air quality and frequent pollution events in recent years. Studying the effect of meteorological conditions on the concentration of pollution aerosols in these pollution sensitive regions is a hot focus now. This paper analyses the characteristics of atmospheric super-saturation and the corresponding H_PMLs (height of supersaturated pollution mixing layer), investigating their contribution to the frequently-seen heavy haze-fog weather. The results suggest that: (1) in the above-mentioned pollution sensitive regions in China, super-saturated layers repeatedly appear in the low altitude and the peak value of supersaturation S can reach 6–10%, which makes pollution particles into the wet adiabatic uplift process in the stable-static atmosphere. After low-level atmosphere reaches the super-saturation state below the H_PMLs, meteorological condition contributes to humidification and condensation of pollution particles. (2) Caculation of condensation function Fc, one of PLAM sensetive parameter, indicates that super-saturation state helps promote condensation, beneficial to the formation of Condensational Kink (CK) in the pollution sensitive areas. This favors the formation of new aerosol particles and intensities the cumulative growth of aerosol concentration. (3) By calculating the convective inhibition energy on average │CIN│ > 1.0 × 104 J kg−1, we found the value is about 100 times higher than the stable critical value. The uplifting diffusion of the particles is inhibited by the ambient airflow. So, this is the important reason for the aggravation and persistence of aerosol pollutants in local areas. (4) H_PMLs is negatively correlated to the pollution meteorological condition index PLAM which can describe the change of PM2.5 concentration. The lower the H_PMLs is, the higher the PLAM becomes, and the more conductive the air condition is to aggravation of pollutant aerosol concentration.
Graphical abstractSchematic diagram of 3-D model for low-level super-saturation layer (H_SSL) and pollution mixing layer (H_PMLs) in the pollution hotspots (NCP, YRD and PRD and SCB) in China. Light blue scarping down to the bottom of the vertical plane (B) is iso-θe surface for air adiabatic uplift; on the upper left corner of B-plane is the tephigram.
HighlightsImpact of the atmospheric super-saturation layer on heavy haze-fog pollution in China.Super-saturation state helps forming Condensational Kink (CK) in the polluted areas.Super-saturation below the height of pollution mixing layer favors the humidification of particles.Highly intensified convective inhibition of ambient atmosphere is favorable for heavy haze-fog.A feedback mechanism of micro-scale pollution processes to large-scale processes is an important reason.
On the influence of atmospheric super-saturation layer on China's heavy haze-fog events
Wang, Jizhi (author) / Yang, Yuanqin (author) / Zhang, Xiaoye (author) / Liu, Hua (author) / Che, Huizheng (author) / Shen, Xiaojing (author) / Wang, Yaqiang (author)
Atmospheric Environment ; 171 ; 261-271
2017-10-14
11 pages
Article (Journal)
Electronic Resource
English
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