title: [Characterization of ultrafine particle size distribution in the urban atmosphere of Hangzhou in spring].
abstract: Continuous measurement and analysis of the atmospheric ultrafine particle number concentration were performed in Hangzhou from March to May, 2012 by using the fast mobility particle sizer (FMPS). The result showed that daily number concentration of nucleation mode (5.6-20 nm), Aitken mode (20-100 nm), and accumulation mode (100-560 nm) particles, and total particles were 0.84 x 10(4), 1.08 x 10(4), 0.47 x 10(4) and 2.38 x 10(4) cm(-3) respectively. The concentration of Aitken mode particles was higher than that of other mode particles in sunny day. The nucleation mode and Aitken mode particles usually started to increase around 10:00-11:00 and ended up after 3-4 h. This indicated the solar radiation promoted the formation of new particles. Human activities caused the concentration distribution of each mode particles having an obvious difference between workdays and weekends. Combined with the meteorological factors, analysis showed that the wind speed and wind direction also directly influenced particulate concentration. The analysis of particulate concentration and visibility showed that the concentration of accumulation mode particles had a negative relationship with the atmospheric visibility, while those of nucleation mode and Aitken mode particles had a slight influence on it.
authors.forename: Xiao-Fang
authors.initials: XF
authors.lastname: Xie
authors.forename: Zai
authors.initials: Z
authors.lastname: Sun
authors.forename: Wen-Jun
authors.initials: WJ
authors.lastname: Yang
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D001272:Atmosphere / Q000032:analysis; D002681:China; D002947:Cities; D004784:Environmental Monitoring; D008685:Meteorological Concepts; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D012621:Seasons; D014919:Wind
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter