关键词: 气溶胶谱分布, 对数正态拟合, 日变化

Abstract: A comprehensive field campaign regarding atmospheric aerosol and chemistry was conducted in suburban Tianjin, from July 11 to August 14, 2009. The dataset of particle number size distributions (0.02?1.00 μm in diameter) was analyzed and parameterized, and was further studied with respect to its diurnal variation and relations with meteorological parameters such as wind speed and wind direction. The hourly-averaged integrated number and volume concentrations are 1.7×10⁴cm^-3 and 59 μm³/cm³ respectively. A diurnal variation of particle number concentration is observed with three peaks (06:00?08:00, 13:00?15:00, and 19:00?21:00), which are highly influenced by traffic density and photochemical nucleation process. Maxima of particle concentration occur with calm winds and show no dependency on wind directions, which suggests that local emission sources contribute mostly to the aerosol pollution. Particle number concentration decreases when wind speed increases, and obtains in a relatively high level when wind from S/SW/SE directions prevails, which implies that local particle concentration is influenced by transport from more polluted areas in the south.

Key words: particle number size distribution, log-normal fitting, diurnal variation