Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Online measurement of carbonaceous aerosols in suburban Shanghai during winter over a three-year period: Temporal variations, meteorological effects, and sources
Abstract Carbonaceous aerosols have adverse effects on both human health and the climate. To understand the temporal variations and sources of carbonaceous aerosols, organic carbon (OC) and elemental carbon (EC) were measured hourly in suburban Shanghai in 2015–2017 during winter. The average OC concentrations were 7.34 ± 4.51 μgC/m3 in 2015, 7.16 ± 4.43 μgC/m3 in 2016, and 6.4 ± 3.22 μgC/m3 in 2017. The EC concentrations decreased significantly each year, with average concentrations of 3.82 ± 2.43, 2.91 ± 2.28, and 2.46 ± 1.88 μgC/m3, respectively, which caused the OC/EC ratio to increase from 2015 to 2017. Although the meteorological conditions differed each winter, there was a similar pattern of OC and EC diurnal variations, with concentrations peaking at 08:00 and 20:00, largely due to rush-hour vehicle emissions. A downward trend of EC/CO and EC/NO2 (mass ratios) but steady CO and NO2 concentrations from 2015 to 2017 revealed that the characteristics of primary vehicle emissions changed, and that less EC was emitted. Secondary organic carbon (SOC) and primary organic carbon (POC) were estimated with the minimum R 2 (MRS) method. The hiemal SOC/OC values in suburban Shanghai were 19.2 ± 18.6% in 2015, 31.1 ± 18.6% in 2016, and 51.0 ± 21.4% in 2017, exhibiting an increasing trend. As the PM2.5 concentration increased (from 0 to 50 μg/m3 to 100–300 μg/m3), a decreasing SOC/OC ratio (from 43.6 ± 23.9% to 21.8 ± 17.7%) was observed over the three years, showing that primary emissions were the main contributors to carbonaceous aerosols on haze days. Case analysis of haze events further demonstrated that the primary sources of OC and EC were vehicle emissions. The contributions of biomass burning and coal combustion to carbonaceous aerosols became less important over the study period. This study highlights the importance of controlling vehicle emissions to reduce carbonaceous aerosol concentrations in the suburbs of the Chinese megacity, Shanghai.
Graphical abstract Display Omitted
Highlights Hourly OC and EC were analyzed at suburban Shanghai in winter 2015 to 2017. SOC/OC decreased with increased PM2.5 pollution. Biomass burning and coal combustion contribution to OC and EC decreased. Vehicle emissions are the dominant source of carbonaceous aeorosols.
Online measurement of carbonaceous aerosols in suburban Shanghai during winter over a three-year period: Temporal variations, meteorological effects, and sources
Abstract Carbonaceous aerosols have adverse effects on both human health and the climate. To understand the temporal variations and sources of carbonaceous aerosols, organic carbon (OC) and elemental carbon (EC) were measured hourly in suburban Shanghai in 2015–2017 during winter. The average OC concentrations were 7.34 ± 4.51 μgC/m3 in 2015, 7.16 ± 4.43 μgC/m3 in 2016, and 6.4 ± 3.22 μgC/m3 in 2017. The EC concentrations decreased significantly each year, with average concentrations of 3.82 ± 2.43, 2.91 ± 2.28, and 2.46 ± 1.88 μgC/m3, respectively, which caused the OC/EC ratio to increase from 2015 to 2017. Although the meteorological conditions differed each winter, there was a similar pattern of OC and EC diurnal variations, with concentrations peaking at 08:00 and 20:00, largely due to rush-hour vehicle emissions. A downward trend of EC/CO and EC/NO2 (mass ratios) but steady CO and NO2 concentrations from 2015 to 2017 revealed that the characteristics of primary vehicle emissions changed, and that less EC was emitted. Secondary organic carbon (SOC) and primary organic carbon (POC) were estimated with the minimum R 2 (MRS) method. The hiemal SOC/OC values in suburban Shanghai were 19.2 ± 18.6% in 2015, 31.1 ± 18.6% in 2016, and 51.0 ± 21.4% in 2017, exhibiting an increasing trend. As the PM2.5 concentration increased (from 0 to 50 μg/m3 to 100–300 μg/m3), a decreasing SOC/OC ratio (from 43.6 ± 23.9% to 21.8 ± 17.7%) was observed over the three years, showing that primary emissions were the main contributors to carbonaceous aerosols on haze days. Case analysis of haze events further demonstrated that the primary sources of OC and EC were vehicle emissions. The contributions of biomass burning and coal combustion to carbonaceous aerosols became less important over the study period. This study highlights the importance of controlling vehicle emissions to reduce carbonaceous aerosol concentrations in the suburbs of the Chinese megacity, Shanghai.
Graphical abstract Display Omitted
Highlights Hourly OC and EC were analyzed at suburban Shanghai in winter 2015 to 2017. SOC/OC decreased with increased PM2.5 pollution. Biomass burning and coal combustion contribution to OC and EC decreased. Vehicle emissions are the dominant source of carbonaceous aeorosols.
Online measurement of carbonaceous aerosols in suburban Shanghai during winter over a three-year period: Temporal variations, meteorological effects, and sources
Yao, Lan (Autor:in) / Huo, Juntao (Autor:in) / Wang, Dongfang (Autor:in) / Fu, Qingyan (Autor:in) / Sun, Wenwen (Autor:in) / Li, Qing (Autor:in) / Chen, Jianmin (Autor:in)
Atmospheric Environment ; 226
11.03.2020
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch