@article{oai:nagoya.repo.nii.ac.jp:00028396,
 author = {Osada, Kazuo and Saito, Shinji and Tsurumaru, Hiroshi and Hoshi, Junya},
 journal = {Atmospheric Environment},
 month = {Jun},
 note = {Concentrations of PM2.5 in Tokyo, a densely populated megacity, often increase because of NH4NO3 formation under low-wind conditions during winter. To obtain source information of NH3 as a NH4NO3 precursor, hourly NH3 and NH4^+ concentrations were measured at an urban site in Tokyo in December 2017. Results show that PM2.5 and NH4^+ concentrations increased simultaneously under low-wind and low-temperature conditions along with NH3, NOx, CO, and optical black carbon (OBC) concentrations. The remaining NH4^+ (herein, ΔNH4^+) subtracted from observed NH4^+ to equivalent SO4^2− concentration correlated well with NO3^− in PM2.5, indicating the existence of fine NH4NO3 particles. Regression analysis of hourly NH3 + ΔΝH4^+ concentrations with CO, NOx, and OBC showed significant correlation. Virtual emission rates (VER) of NH3 per motor vehicle in Tokyo were estimated using observed relations between NH3 + ΔΝH4^+ and OBC, etc. with data from vehicular statistics: they were 3.7–32 mg/km. The regression of NH3 + ΔΝH4^+ with OBC concentrations indicated an intercept of about 3.2 ppb, which is about half of the monthly average in December. This result implies that the non-vehicular source strength was nearly the same strength as the bulk vehicular emissions of NH3 during winter in Tokyo., ファイル公開：2021-06-01},
 pages = {218--224},
 title = {Vehicular exhaust contributions to high NH3 and PM2.5 concentrations during winter in Tokyo, Japan},
 volume = {206},
 year = {2019}
}