Ambient benzene homologues were measured at a site in the northeastern urban area of Beijing, China, from August 24 to September 4, 2012 by SUMMA canister sampling followed by laboratory determination using cryogenic ...Ambient benzene homologues were measured at a site in the northeastern urban area of Beijing, China, from August 24 to September 4, 2012 by SUMMA canister sampling followed by laboratory determination using cryogenic cold trap pre-concentration-GC-MS/FID, and their health risks were also assessed. Daily total benzene homologues ranged from 0.99 to 49.71 μg/m3 with an average of 11.98 μg/m3. Benzene homologues showed higher concentrations in the morning and evening than that at noontime. Comparison with previous studies revealed a trend of decrease for ambient benzene homologues probably due to the effective emission control in Beijing in recent years. Vehicular exhaust was the main source while volatilization of paints and solvents also made substantial contributions. Health risk assessment showed that BTEX （benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene） and styrene had no appreciable adverse non-cancer health risks for the exposed population, while benzene has potential cancer risk of 1.34E-05. Available data from cities in China all implied that benzene imposes relatively higher cancer risk on the exposed populations and therefore strict control measures should be taken to further lower ambient benzene levels in China.展开更多
Benzene is a carcinogenic air pollutant for which European legislation has set an annual limit and criteria for the number of fixed monitoring sites within air quality networks(AQMN).However,due to the limited number ...Benzene is a carcinogenic air pollutant for which European legislation has set an annual limit and criteria for the number of fixed monitoring sites within air quality networks(AQMN).However,due to the limited number of fixed sites for benzene measurement,exposure data are lacking.Considering the relationship between benzene levels and other variables monitored within an AQMN,such as NO_(2),O_(3),temperature,solar radiation,and accumulated precipitation,this study proposes an approach for estimating benzene air concentrations from the related variables.Using the data of the aforementioned variables from23 fixed stations during 2016-2017,the proposed approach was able to forecast benzene concentration for 2018 with high confidence,providing enriched data on benzene exposure and its trends.Moreover,the spatial distribution of the estimated versus the most representative benzene levels was quite similar.Finally,an artificial neural network identified the most representative fixed benzene monitoring sites within the AQMN.展开更多
基金supported by the Special Research Project for the National Environmental Protection Public Welfare Industry of China(No.201009032)the Strategic Pilot Science and Technology Project of Chinese Academy of Sciences(Class B)(No.XDB05010200)the Project of National Natural Science Foundation of China(No.41175111)
文摘Ambient benzene homologues were measured at a site in the northeastern urban area of Beijing, China, from August 24 to September 4, 2012 by SUMMA canister sampling followed by laboratory determination using cryogenic cold trap pre-concentration-GC-MS/FID, and their health risks were also assessed. Daily total benzene homologues ranged from 0.99 to 49.71 μg/m3 with an average of 11.98 μg/m3. Benzene homologues showed higher concentrations in the morning and evening than that at noontime. Comparison with previous studies revealed a trend of decrease for ambient benzene homologues probably due to the effective emission control in Beijing in recent years. Vehicular exhaust was the main source while volatilization of paints and solvents also made substantial contributions. Health risk assessment showed that BTEX （benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene） and styrene had no appreciable adverse non-cancer health risks for the exposed population, while benzene has potential cancer risk of 1.34E-05. Available data from cities in China all implied that benzene imposes relatively higher cancer risk on the exposed populations and therefore strict control measures should be taken to further lower ambient benzene levels in China.
文摘Benzene is a carcinogenic air pollutant for which European legislation has set an annual limit and criteria for the number of fixed monitoring sites within air quality networks(AQMN).However,due to the limited number of fixed sites for benzene measurement,exposure data are lacking.Considering the relationship between benzene levels and other variables monitored within an AQMN,such as NO_(2),O_(3),temperature,solar radiation,and accumulated precipitation,this study proposes an approach for estimating benzene air concentrations from the related variables.Using the data of the aforementioned variables from23 fixed stations during 2016-2017,the proposed approach was able to forecast benzene concentration for 2018 with high confidence,providing enriched data on benzene exposure and its trends.Moreover,the spatial distribution of the estimated versus the most representative benzene levels was quite similar.Finally,an artificial neural network identified the most representative fixed benzene monitoring sites within the AQMN.
