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Evolution of mixing state of black carbon in polluted air from Tokyo
Author(s) -
Shiraiwa M.,
Kondo Y.,
Moteki N.,
Takegawa N.,
Miyazaki Y.,
Blake D. R.
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2007gl029819
Subject(s) - aerosol , soot , mixing ratio , carbon black , sulfate , nitrate , trace gas , environmental science , environmental chemistry , mass spectrometry , analytical chemistry (journal) , atmospheric sciences , chemistry , combustion , geology , natural rubber , organic chemistry , chromatography
The evolution of the mixing state of black carbon aerosol (BC) was investigated using a single‐particle soot photometer (SP2) in polluted air transported from Tokyo. Ground‐based measurements of aerosols and trace gases were conducted at a suburban site (Kisai) 50 km north of Tokyo during July–August 2004. The ratio of 2‐pentyl nitrate (2‐PeONO 2 ) to n ‐pentane ( n ‐C 5 H 12 ) was used to derive the photochemical age. According to the SP2 measurement, the number fraction of thickly coated BC (Shell/Corel Ratio > ca. 2) with a core diameter of 180 nm increased at the rate of 1.9% h −1 , as the photochemical clock proceeded under land‐sea breeze circulation. Positive matrix factorization was applied to investigate the time‐dependent contributions of different coating materials using the mass concentrations of sulfate, nitrate, and organics measured using an aerosol mass spectrometer. The main coating materials found in this study were sulfate and organics.