title: Number concentration and size distribution of ultrafine particles on the roadside of the Tateyama-Kurobe Alpine route, Japan.
abstract: Measurements of ultrafine particles (UFPs) with diameters smaller than 100 nm were made with a Scanning Mobility Particle Sizer on the roadside of the Tateyama-Kurobe Alpine route on the western slope of Mt. Tateyama, Japan, in the summer and autumn of 2007 and 2008. The number concentrations of nanoparticles (NPs) with diameters smaller than 50 nm increased sharply in the morning. This increase agreed with that of the NO concentration, which is a good indicator of vehicle emissions. Although the peak concentration of NO was also detected in the late afternoon, the concentrations of NPs did not increase. The vehicle emission of UFPs may vary considerably with the driving conditions. The emission of NPs might have been accelerated under a high engine-load condition. The NP concentrations in October were much higher than those in August, although there were more buses in August than in October. The number size distribution in the morning was bimodal, with the first peak around 20-30 nm and the second one around 70-80 nm. The first peak became small during the daytime. The first peak disappeared, and a small second peak remained through midnight.
authors: Toyama Prefectural University, Toyama, Japan. nabe@pu-toyama.ac.jp
authors: Koichi
authors: K
authors: Watanabe
authors: Hideharu
authors: H
authors: Honoki
authors: Fuminori
authors: F
authors: Endo
authors: Takashi
authors: T
authors: Murakami
authors: Yuki
authors: Y
authors: Yoshida
authors: Hajime
authors: H
authors: Iida
authors: Yoshitoshi
authors: Y
authors: Uehara
authors: Atsushi
authors: A
authors: Kume
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000531:Altitude; D004784:Environmental Monitoring; D007564:Japan; D053758:Nanoparticles / Q000032:analysis; D010316:Particle Size; D012621:Seasons; D001335:Vehicle Emissions / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions