Polycyclic aromatic hydrocarbons(PAHs)and their nitrated derivatives(NPAHs)attract continuous attention due to their outstanding carcinogenicity and mutagenicity.In order to investigate the diurnal variations,sources,...Polycyclic aromatic hydrocarbons(PAHs)and their nitrated derivatives(NPAHs)attract continuous attention due to their outstanding carcinogenicity and mutagenicity.In order to investigate the diurnal variations,sources,formation mechanism,and health risk assessment of them in heating season,particulate matter(PM)were collected in Beijing urban area from December 26,2017 to January 17,2018.PAHs and NPAHs in PM were quantitatively analyzed via gas chromatography-mass spectrometry(GC-MS).Average daily concentrations of PAHs and NPAHs were(78±54)ng/m^(3)and(783±684)pg/m^(3),respectively.The concentrations of them were significantly higher at nighttime than at daytime,and NPAHs concentrations were 1-2 orders of magnitude lower than PAHs concentrations.In the heating season,the dominant species of PAHs include benzo[b]fluoranthene,fluoranthene,pyrene,and chrysene,while 9-nitroanthracene,2+3-nitrofluoranthene,and 2-nitropyrene were dominant species for NPAHs.NPAHs were found to have a single peak during heating and to be primarily distributed in the 0.4-0.7μm particle size.Primary emissions such as biomass burning,coal combustion,and traffic emissions were the major sources of PAHs.NPAHs were produced by the primary source of vehicle emissions and the secondary reaction triggered by OH radicals,as well as biomass burning during daytime.According to the health risk assessment,the total carcinogenic risk was higher in adults than in children.While upon oral ingestion,the carcinogenic risk in children was higher than that of adults,but the risk of adults was higher than children through skin contact and respiratory inhalation.展开更多
Urbanization has introduced a series of environmental problems worldwide,and particulate matter(PM)is one of the main threats to human health.Due to the lack of high-resolution,large-scale monitoring data,few studies ...Urbanization has introduced a series of environmental problems worldwide,and particulate matter(PM)is one of the main threats to human health.Due to the lack of high-resolution,large-scale monitoring data,few studies have analyzed the intraurban spatial distribution pattern of PM at a fine scale.In this study,portable air monitors carried by five taxis were used to collect the concentrations of PM1,PM2.5 and PM10 for five months in Shenyang during the heating season.The results showed that high concentrations of PM were distributed in the suburbs,while relatively low concentration areas were found in the central area.Agricultural,industrial and development zones had higher concentration values among the eight observed types.The PM concentration exhibited strong spatial autocorrelation based on Moran’s I index analysis.Meteorological factors were the most important influencing factors of the three pollutants,and their total contribution rate accounted for more than 80%among the 13 factors according to boosted regression trees analysis.The taxi monitoring method we proposed was a more efficient and feasible method for monitoring urban air pollution and could obtain higher spatial-temporal resolution data at a lower cost to elucidate the region’s dynamic air pollution distribution patterns.展开更多
The aim of the study is to investigate the influence of geometry on the thermal capacity and stratifications of a water pit heat storage for solar district heating.A TRNSYS component model for a truncated cone water p...The aim of the study is to investigate the influence of geometry on the thermal capacity and stratifications of a water pit heat storage for solar district heating.A TRNSYS component model for a truncated cone water pit was developed based on the coordinate transformation method and validated by experimental results from the water pit heat storage in Huangdicheng in 2018.The thermal performance of 26 water pits with different heights and side wall slopes was calculated for 10 consecutive years.It takes four to six years for the water pit to reach steady-state operation.The operation data from the tenth year was selected to evaluate the thermal performance of each configuration.The results show that because of the thermal insulation on top of the water pit,the height to diameter ratio of a water pit with minimum annual heat loss was always smaller than 1.0.The annual storage efficiency of a water pit increases with side wall slope due to the reduced side wall area.There is an almost linear increase in the thermal stratification number of a water pit with height.With an increase in the height,thermal stratification in water pits with a steeper slope increased more gradually than water pits with a lower slope.The findings in this paper are relevant for the design optimization of water pits as seasonal thermal energy storages.展开更多
基金supported by the National Natural Science Foundation of China(No.41907197)the Fundamental Research Funds for Central Public Welfare Scientific Research Institutes of China,Chinese Research Academy of Environmental Sciences(No.2019YSKY-018)+1 种基金the National Key R&D Program of China(No.2019YFC0214800)the Standard System and Key Standards Research of National Ecological Environment Protection and Risk Prevention(No.2020YFC18063)。
文摘Polycyclic aromatic hydrocarbons(PAHs)and their nitrated derivatives(NPAHs)attract continuous attention due to their outstanding carcinogenicity and mutagenicity.In order to investigate the diurnal variations,sources,formation mechanism,and health risk assessment of them in heating season,particulate matter(PM)were collected in Beijing urban area from December 26,2017 to January 17,2018.PAHs and NPAHs in PM were quantitatively analyzed via gas chromatography-mass spectrometry(GC-MS).Average daily concentrations of PAHs and NPAHs were(78±54)ng/m^(3)and(783±684)pg/m^(3),respectively.The concentrations of them were significantly higher at nighttime than at daytime,and NPAHs concentrations were 1-2 orders of magnitude lower than PAHs concentrations.In the heating season,the dominant species of PAHs include benzo[b]fluoranthene,fluoranthene,pyrene,and chrysene,while 9-nitroanthracene,2+3-nitrofluoranthene,and 2-nitropyrene were dominant species for NPAHs.NPAHs were found to have a single peak during heating and to be primarily distributed in the 0.4-0.7μm particle size.Primary emissions such as biomass burning,coal combustion,and traffic emissions were the major sources of PAHs.NPAHs were produced by the primary source of vehicle emissions and the secondary reaction triggered by OH radicals,as well as biomass burning during daytime.According to the health risk assessment,the total carcinogenic risk was higher in adults than in children.While upon oral ingestion,the carcinogenic risk in children was higher than that of adults,but the risk of adults was higher than children through skin contact and respiratory inhalation.
基金Funding for this project was provided by the National Natural Science Foundation of China(Nos.41730647 and 32071580)。
文摘Urbanization has introduced a series of environmental problems worldwide,and particulate matter(PM)is one of the main threats to human health.Due to the lack of high-resolution,large-scale monitoring data,few studies have analyzed the intraurban spatial distribution pattern of PM at a fine scale.In this study,portable air monitors carried by five taxis were used to collect the concentrations of PM1,PM2.5 and PM10 for five months in Shenyang during the heating season.The results showed that high concentrations of PM were distributed in the suburbs,while relatively low concentration areas were found in the central area.Agricultural,industrial and development zones had higher concentration values among the eight observed types.The PM concentration exhibited strong spatial autocorrelation based on Moran’s I index analysis.Meteorological factors were the most important influencing factors of the three pollutants,and their total contribution rate accounted for more than 80%among the 13 factors according to boosted regression trees analysis.The taxi monitoring method we proposed was a more efficient and feasible method for monitoring urban air pollution and could obtain higher spatial-temporal resolution data at a lower cost to elucidate the region’s dynamic air pollution distribution patterns.
基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA21050200)the Guangdong Innovative and Entrepreneurial Research Team Program(No.2013N070)the State Grid Corporation Science and Technology Project“Research on Comprehensive Development and Utilization Technology of Renewable Energy in Multi-format Ecological Development Zone”for funding this project.
文摘The aim of the study is to investigate the influence of geometry on the thermal capacity and stratifications of a water pit heat storage for solar district heating.A TRNSYS component model for a truncated cone water pit was developed based on the coordinate transformation method and validated by experimental results from the water pit heat storage in Huangdicheng in 2018.The thermal performance of 26 water pits with different heights and side wall slopes was calculated for 10 consecutive years.It takes four to six years for the water pit to reach steady-state operation.The operation data from the tenth year was selected to evaluate the thermal performance of each configuration.The results show that because of the thermal insulation on top of the water pit,the height to diameter ratio of a water pit with minimum annual heat loss was always smaller than 1.0.The annual storage efficiency of a water pit increases with side wall slope due to the reduced side wall area.There is an almost linear increase in the thermal stratification number of a water pit with height.With an increase in the height,thermal stratification in water pits with a steeper slope increased more gradually than water pits with a lower slope.The findings in this paper are relevant for the design optimization of water pits as seasonal thermal energy storages.
