In this study,the black carbon (BC) measurements in the atmosphere of Nanjing,China were continuously conducted from 2015 to 2018 using a Model AE-33 aethalometer.By combining dataset of PM_(2.5),PM_(10),CO,NO_2,SO_2,...In this study,the black carbon (BC) measurements in the atmosphere of Nanjing,China were continuously conducted from 2015 to 2018 using a Model AE-33 aethalometer.By combining dataset of PM_(2.5),PM_(10),CO,NO_2,SO_2,O_3 and meteorological parameters,the temporal variations and the source apportionment of BC were given in this study.The results showed that the PM_(2.5) mass concentrations decreased in Nanjing,with an average annual rate of variation of 6.50μg/(m^3·year).Differently,the annual average concentrations of BC increased with an average annual variation rate of 214.71 ng/(m^3·year).The seasonal variations showed the pattern of BC mass concentrations in winter>autumn>spring>summer.The diurnal variations of BC mass concentrations showed a double-peak in all four seasons.The first peak occurred at approximately 7:00 in spring,summer and autumn and around 8:00 in winter.The second peak took place after 18:00.The average AAE (absorption ?ngstr?m exponent) was 1.26 with a maximum of 1.35 during wintertime and the lowest(1.12) during summertime.In addition,the AAE was smaller in the daytime than that at night,with a minimum occurring between 13:00 and 14:00.BC and visibility show a good power-function relationship at different humidity levels.The average values of the visibility thresholds of the BC mass concentrations in spring,summer,autumn and winter were 1.326,5.522,1.340 and 0.708μg/m^3,respectively.The greater the relative humidity,the smaller the visibility threshold for the BC mass concentrations was.展开更多
基金supported by the National Natural Science Foundation of China (Nos.91644224 and 41805096)the special fund of State Key Joint Laboratory of Environment Simulation and Pollution Control (No.19K03ESPCP)+1 种基金the Natural Science Foundation of Jiangsu Province (No.BK20180801)the Natural Science Research Project for Universities of Jiangsu Province,China (No.18KJB170011)。
文摘In this study,the black carbon (BC) measurements in the atmosphere of Nanjing,China were continuously conducted from 2015 to 2018 using a Model AE-33 aethalometer.By combining dataset of PM_(2.5),PM_(10),CO,NO_2,SO_2,O_3 and meteorological parameters,the temporal variations and the source apportionment of BC were given in this study.The results showed that the PM_(2.5) mass concentrations decreased in Nanjing,with an average annual rate of variation of 6.50μg/(m^3·year).Differently,the annual average concentrations of BC increased with an average annual variation rate of 214.71 ng/(m^3·year).The seasonal variations showed the pattern of BC mass concentrations in winter>autumn>spring>summer.The diurnal variations of BC mass concentrations showed a double-peak in all four seasons.The first peak occurred at approximately 7:00 in spring,summer and autumn and around 8:00 in winter.The second peak took place after 18:00.The average AAE (absorption ?ngstr?m exponent) was 1.26 with a maximum of 1.35 during wintertime and the lowest(1.12) during summertime.In addition,the AAE was smaller in the daytime than that at night,with a minimum occurring between 13:00 and 14:00.BC and visibility show a good power-function relationship at different humidity levels.The average values of the visibility thresholds of the BC mass concentrations in spring,summer,autumn and winter were 1.326,5.522,1.340 and 0.708μg/m^3,respectively.The greater the relative humidity,the smaller the visibility threshold for the BC mass concentrations was.
