期刊文献+
共找到5篇文章
< 1 >
每页显示 20 50 100
Black Carbon Particles in the Urban Atmosphere in Beijing 被引量:11
1
作者 王庚辰 白建辉 +1 位作者 孔琴心 Alexander EMILENKO 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2005年第5期640-646,共7页
A study of the concentration of black carbon particles and its variation in the urban atmosphere has been carried out since 1996 in the Beijing area. The measurements were done in the late autumn and early winter each... A study of the concentration of black carbon particles and its variation in the urban atmosphere has been carried out since 1996 in the Beijing area. The measurements were done in the late autumn and early winter each year, the period before and after domestic heating activities begin. The results show the presence of black carbon particles at the high level that vary over a large range in the urban atmosphere in Beijing. The mean value of daily average concentration for the whole observation period of 1996-2004 is 20.0 μgm^-3. An evident decrease of black carbon particle concentration in the Beijing area is observed after 2000, and the daily average concentration of black carbon particles is estimated to be 16.0 μgm^-3 with a variation range of 2.10-50.50 μgm^-3 for the period of 2000-2004. The observation method and main variation behavior characteristics of black carbon particles in the urban atmosphere in the Beijing area are given and discussed. 展开更多
关键词 black carbon particles urban atmosphere AEROSOLS BEIJING
下载PDF
Prediction of SO_2 Concentration in Urban Atmosphere Based on B-P Neural Network 被引量:1
2
作者 姚建 王丽梅 袁野 《Meteorological and Environmental Research》 CAS 2010年第11期9-11,14,共4页
Base on the principle and method of B-P neural network,the prediction model of SO2 concentration in urban atmosphere was established by using the statistical data of a city in southwest China from 1991 to 2009,so as t... Base on the principle and method of B-P neural network,the prediction model of SO2 concentration in urban atmosphere was established by using the statistical data of a city in southwest China from 1991 to 2009,so as to forecast atmospheric SO2 concentration in a city of southwest China.The results showed that B-P neural network applied in the prediction of SO2 concentration in urban atmosphere was reasonable and efficient with high accuracy and wide adaptability,so it was worthy to be popularized. 展开更多
关键词 B-P neural network SO2 concentration in urban atmospheric Prediction model China
下载PDF
Quantitative relationship between visibility and mass concentration of PM2.5 in Beijing 被引量:31
3
作者 WANG Jing-li ZHANG Yuan-hang +4 位作者 SHAO Min LIU Xu-lin ZENG Li-min CHENG Cong-lan XU Xiao-feng 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2006年第3期475-481,共7页
The pollution of particulate matter less than 2.5μm (PM2.5) is a serious environmental problem in Beijing. The annual average concentration of PM2.5 in 2001 from seasonal monitor results was more than 6 times that ... The pollution of particulate matter less than 2.5μm (PM2.5) is a serious environmental problem in Beijing. The annual average concentration of PM2.5 in 2001 from seasonal monitor results was more than 6 times that of the U,S, national ambient air quality standards proposed by U.S. EPA. The major contributors to mass of PM2.5 were organics, crustal elements and sulfate. The chemical composition of PM2.5 varied largely with season, but was similar at different monitor stations in the same season. The fine particles (PM2.5) cause atmospheric visibility deterioration through light extinction, The mass concentrations of PM2.5 were anti-correlated to the visibility, the best fits between atmospheric visibility and the mass concentrations of PM2.5 were somehow different: power in spring, exponential in summer, logarithmic in autumn, power or exponential in winter. As in each season the meteorological parameters such as air temperature and relative humidity change from day to day, probably the reason of above correlations between PM2.5 and visibility obtained at different seasons come from the differences in chemical compositions of PM2.5. 展开更多
关键词 PM2.5 atmospheric urban aerosol air pollution meteorological factor VISIBILITY
下载PDF
A composite model for complex building street configuration in a large eddy simulation of local urban atmospheric environment 被引量:3
4
作者 LIU YuShi CUI GuiXiang +3 位作者 WANG ZhiShi HUANG WeiXi XU ChunXiao ZHANG ZhaoShun 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2011年第4期716-723,共8页
The wind field and pollutant dispersion are predicted numerically in a local urban area with crowded buildings and heavy traffic.A domain decomposition method is used in the large eddy simulation,in which the urban ar... The wind field and pollutant dispersion are predicted numerically in a local urban area with crowded buildings and heavy traffic.A domain decomposition method is used in the large eddy simulation,in which the urban area is decomposed into a central area,where pollution is the major concern,and a surrounding region,where the pollutant distribution is not important.The composite model is proposed for the complex building-street layout.The fine grid mesh is used to resolve the buildings in the central area while the buildings are treated as roughness elements in the surrounding region where the coarse grids are used.The proposed numerical method is applied to simulate the wind field and pollutant dispersion from vehicle exhaust in the Rua Do Campo area of Macao.The results show that the composite model is an appropriate method for predicting wind field and pollutant dispersion in the crowded building area. 展开更多
关键词 large eddy simulation drag element method urban atmospheric environment
原文传递
Atmospheric environmental capacity and urban atmospheric load in China's Mainland 被引量:8
5
作者 XU DaHai WANG Yu ZHU Rong 《Science China Earth Sciences》 SCIE EI CAS CSCD 2018年第1期33-46,共14页
Daily and annual average atmospheric environmental capacity coefficient(A-value) sequences for China's Mainland are calculated from hourly data recorded at 378 ground stations over 1975–2014. A-values at differen... Daily and annual average atmospheric environmental capacity coefficient(A-value) sequences for China's Mainland are calculated from hourly data recorded at 378 ground stations over 1975–2014. A-values at different recurrence intervals are calculated by fitting the sequences to Pearson type III distribution curves. Based on these A-values and source-sink balance(reference concentration 100 μg m^(-3)), atmospheric environmental capacities at the recurrence intervals are calculated for all of China's Mainland and each provincial administrative region. The climate average atmospheric environmental capacity reference value for the entire mainland is 2.169×10~7 t yr^(-1). An urban atmospheric load index is defined for analyses of the impact of population density on the urban atmospheric environment. Analyses suggest that this index is also useful for differentiating whether air quality changes are attributable to varying meteorological conditions or variations of artificial emission rate.Equations guiding the control of unorganized emission sources are derived for preventing air quality deterioration during urban expansion and population concentration. 展开更多
关键词 Atmospheric environmental capacity Pearson type III distribution Recurrence interval urban atmospheric load index Emission rate density
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部