A field measurement campaign was carried out during the late winter and early spring of2015 in Budapest, the capital of Hungary. The size distribution(SD) and optical absorption of carbonaceous particulate matter(CPM)...A field measurement campaign was carried out during the late winter and early spring of2015 in Budapest, the capital of Hungary. The size distribution(SD) and optical absorption of carbonaceous particulate matter(CPM) was measured online using a Scanning Mobility Particle Sizer(SMPS), a 7λ-aethalometer and an inhouse developed 4λ-Photoacoustic Spectrometer. Based on the SD data, the measurement period could be classified into days with and without new particle formation events(normal days and nucleation days),although particular nucleation-like events were observed on normal days as well. Three characteristic size modes were observed with CMDs of circa 15, 25 and 110 nm that corresponded to the nucleation, traffic and heating modes. Based on the temporal behavior of these modes both types of days were divided into distinctive daily periods(heating hours,traffic hours and nucleation hours). The optical absorption spectra(OAC and AAE) also displayed the same part of day behavior to that of SD. That way this paper is among the first to assess the optical response of urban nucleation events. Due to the simultaneous measurement of OAC by the 7λ-aethalometer and a 4λ-Photoacoustic Spectrometer, OAC was measured overall at 11 wavelengths. That way aethalometer correction factors(f and C)were determined at all aethalometer wavelengths using in situ reference photoacoustic measurements. Correction factors were found to have both wavelength and time of the day variation. In the case of f, no clear trend could be observed, however, Cref values increased both as a function of wavelength.展开更多
Black carbon（BC） particles play a unique and important role in earth’s climate system.BC was measured（in-situ） in the central part of the Indo-Gangetic Plains（IGP） at Varanasi,which is a highly populated and po...Black carbon（BC） particles play a unique and important role in earth’s climate system.BC was measured（in-situ） in the central part of the Indo-Gangetic Plains（IGP） at Varanasi,which is a highly populated and polluted region due to its topography and extensive emission sources.The annual mean BC mass concentration was 8.92 ± 7.0 μg m-3,with 34%of samples exceeding the average value.Seasonally,BC was highest during the post-monsoon and winter periods（approximately 18 μg m-3） and lower in the premonsoon/monsoon seasons（approximately 6 μg m-3）.The highest frequency（approximately 46%） observed for BC mass was in the interval from 5 to 10 μg m-3.However,during the post-monsoon season,the most common values（approximately 23%） were between 20 and 25 μg m-3.The nighttime concentrations of BC were approximately twice as much as the daytime values because of lower boundary layer heights at nighttime.The Angstrom exponent was significantly positively correlated（0.55） with ground-level BC concentrations,indicating the impact of BC on the columnar aerosol properties.The estimated mean absorption Angstrom exponent was 1.02 ± 0.08 μg m-3,indicating that the major source of BC was from fossil fuel combustion.Significant negative correlations between BC mass and meteorological parameters indicate a pronounced effect of atmospheric dynamics on the BC mass in this region.The highest mean BC mass concentration（18.1 ± 6.9 μg m-3） as a function of wind speed was under calm wind conditions（38%of the time）.展开更多
基金supported by the project GINOP-2.3.2-15-2016-00036supported by the European Union,co-financed by the European Social Fund under project number EFOP-3.6.1-16-2016-00014
文摘A field measurement campaign was carried out during the late winter and early spring of2015 in Budapest, the capital of Hungary. The size distribution(SD) and optical absorption of carbonaceous particulate matter(CPM) was measured online using a Scanning Mobility Particle Sizer(SMPS), a 7λ-aethalometer and an inhouse developed 4λ-Photoacoustic Spectrometer. Based on the SD data, the measurement period could be classified into days with and without new particle formation events(normal days and nucleation days),although particular nucleation-like events were observed on normal days as well. Three characteristic size modes were observed with CMDs of circa 15, 25 and 110 nm that corresponded to the nucleation, traffic and heating modes. Based on the temporal behavior of these modes both types of days were divided into distinctive daily periods(heating hours,traffic hours and nucleation hours). The optical absorption spectra(OAC and AAE) also displayed the same part of day behavior to that of SD. That way this paper is among the first to assess the optical response of urban nucleation events. Due to the simultaneous measurement of OAC by the 7λ-aethalometer and a 4λ-Photoacoustic Spectrometer, OAC was measured overall at 11 wavelengths. That way aethalometer correction factors(f and C)were determined at all aethalometer wavelengths using in situ reference photoacoustic measurements. Correction factors were found to have both wavelength and time of the day variation. In the case of f, no clear trend could be observed, however, Cref values increased both as a function of wavelength.
基金Supported by the Indian Space Research Organization(ISRO)"Aerosol Radiative Forcing over India"Program at Bananas Hindu University(P32/15 and P32/14)
文摘Black carbon（BC） particles play a unique and important role in earth’s climate system.BC was measured（in-situ） in the central part of the Indo-Gangetic Plains（IGP） at Varanasi,which is a highly populated and polluted region due to its topography and extensive emission sources.The annual mean BC mass concentration was 8.92 ± 7.0 μg m-3,with 34%of samples exceeding the average value.Seasonally,BC was highest during the post-monsoon and winter periods（approximately 18 μg m-3） and lower in the premonsoon/monsoon seasons（approximately 6 μg m-3）.The highest frequency（approximately 46%） observed for BC mass was in the interval from 5 to 10 μg m-3.However,during the post-monsoon season,the most common values（approximately 23%） were between 20 and 25 μg m-3.The nighttime concentrations of BC were approximately twice as much as the daytime values because of lower boundary layer heights at nighttime.The Angstrom exponent was significantly positively correlated（0.55） with ground-level BC concentrations,indicating the impact of BC on the columnar aerosol properties.The estimated mean absorption Angstrom exponent was 1.02 ± 0.08 μg m-3,indicating that the major source of BC was from fossil fuel combustion.Significant negative correlations between BC mass and meteorological parameters indicate a pronounced effect of atmospheric dynamics on the BC mass in this region.The highest mean BC mass concentration（18.1 ± 6.9 μg m-3） as a function of wind speed was under calm wind conditions（38%of the time）.
