Wildfires burn approximately 3%4%of the global land area annually,resulting in massive emissions of greenhouse gases and air pollutants.Over the past two decades,there has been a declining trend in both global burned ...Wildfires burn approximately 3%4%of the global land area annually,resulting in massive emissions of greenhouse gases and air pollutants.Over the past two decades,there has been a declining trend in both global burned area and wildfire emissions.This trend is largely attributed to a decrease in wildfire activity in Africa,which accounts for a substantial portion of the total burned area and emissions.However,the northern high-latitude regions of Asia and North America have witnessed substantial interannual variability in wildfire activity,with several severe events occurring in recent years.Climate plays a pivotal role in influencing wildfire activity and has led to more wildfires in high-latitude regions.These wildfires pose significant threats to climate,ecosystems,and human health.Given recent changes in wildfire patterns and their impacts,it is critical to understand the contributors of wildfires,focus on deteriorating high-latitude areas,and address health risks in poorly managed areas tomitigate wildfire effects.展开更多
Located in the central area of the North China Plain, the Beijing-Tianjin-Hebei region experiences severe air pollution, especially for Hebei province with five cities among the top 10 cities with the worst air qualit...Located in the central area of the North China Plain, the Beijing-Tianjin-Hebei region experiences severe air pollution, especially for Hebei province with five cities among the top 10 cities with the worst air quality nationwide. However, less studies have investigated local and regional contributions to cities in Hebei in comparison to Beijing and Tianjin. In this study, a source-oriented version of the Community Multiscale Air Quality (CMAQ) model is used to quantify inter- and intra-province transport of PM_(2.5) in 11 cities within Hebei in 2017. PM_(2.5) and its components vary seasonally with high levels in winter and low levels in summer. Local contributions to total PM_(2.5) within cities are 23%–61%, while intra-province transport contributes 10%–30%, and inter-province transport contributes 23%–46%, with top contributors of Shandong (4%–22%), Henan (3%–15%) and Shanxi (2%–11%). The primary components in most cities are mainly from local sources (30%–80%), and the secondary components are mainly from inter-province contributions (30%–66%). Local sources have the highest contributions to total PM_(2.5) in Shijiazhuang (∼49%), followed by Shanxi (∼12%) and Xingtai (∼7%). Secondary components from local and intra-province emissions are the major cause of heavy pollution events. These results suggest that both local and regional joint control measures with neighboring cities and provinces are necessary for pollution reduction in Hebei cities.展开更多
基金supported by the National Natural Science Foundation of China(Nos.42077194,42061134008,and 42377098)the Shanghai International Science and Technology Partnership Project(China)(No.21230780200)the Shanghai General Project(China)(No.23ZR1406100).
文摘Wildfires burn approximately 3%4%of the global land area annually,resulting in massive emissions of greenhouse gases and air pollutants.Over the past two decades,there has been a declining trend in both global burned area and wildfire emissions.This trend is largely attributed to a decrease in wildfire activity in Africa,which accounts for a substantial portion of the total burned area and emissions.However,the northern high-latitude regions of Asia and North America have witnessed substantial interannual variability in wildfire activity,with several severe events occurring in recent years.Climate plays a pivotal role in influencing wildfire activity and has led to more wildfires in high-latitude regions.These wildfires pose significant threats to climate,ecosystems,and human health.Given recent changes in wildfire patterns and their impacts,it is critical to understand the contributors of wildfires,focus on deteriorating high-latitude areas,and address health risks in poorly managed areas tomitigate wildfire effects.
基金supported by the co-fund DFG-NSFC Sino-German AirChanges project(No.448720203)National Natural Science Foundation of China(No.42077194 and No.42061134008)Shanghai International Science and Technology Partnership Project(No.21230780200).
文摘Located in the central area of the North China Plain, the Beijing-Tianjin-Hebei region experiences severe air pollution, especially for Hebei province with five cities among the top 10 cities with the worst air quality nationwide. However, less studies have investigated local and regional contributions to cities in Hebei in comparison to Beijing and Tianjin. In this study, a source-oriented version of the Community Multiscale Air Quality (CMAQ) model is used to quantify inter- and intra-province transport of PM_(2.5) in 11 cities within Hebei in 2017. PM_(2.5) and its components vary seasonally with high levels in winter and low levels in summer. Local contributions to total PM_(2.5) within cities are 23%–61%, while intra-province transport contributes 10%–30%, and inter-province transport contributes 23%–46%, with top contributors of Shandong (4%–22%), Henan (3%–15%) and Shanxi (2%–11%). The primary components in most cities are mainly from local sources (30%–80%), and the secondary components are mainly from inter-province contributions (30%–66%). Local sources have the highest contributions to total PM_(2.5) in Shijiazhuang (∼49%), followed by Shanxi (∼12%) and Xingtai (∼7%). Secondary components from local and intra-province emissions are the major cause of heavy pollution events. These results suggest that both local and regional joint control measures with neighboring cities and provinces are necessary for pollution reduction in Hebei cities.
