大气气溶胶粒子质量浓度分布规律研究

Study on Law of Mass Concentration Distribution of Atmospheric Aerosols

在可吸入性颗粒物粒径范围内(d_p<10μm),上海市区大气中气溶胶粒子质量浓度分布为双峰型,峰值出现在1.0μm左右(积聚模态粒子区)和4.5μm左右(粗粒子区),且呈现大粒径处峰值大于小粒径处峰值的趋势。与质量浓度分布曲线相似,质量概率密度分布也为双峰型,峰值出现在0.8μm左右和4.0μm左右。模拟结果表明,上海市区大气中气溶胶粒子质量概率密度分布规律符合双重分布函数:y=exp[-(a_4d^4+a_3d^3+a_2d^2+a_1d+a_0)],所表征的类型,应用双重分布函数能解释大气气溶胶粒子的分布规律。

The mass concentration distribution of atmospheric aerosols in Shanghai proper is bimodal with one peak at 1.0μm (accumulative particles) and another peak at 4.5μm (coase particles) in diameter less than 10μm. Similar to mass distribution, the frequency distribution is also bimodal with one peak at 0.8μm (accumulative particles) and another peak at 4.0μm (coarse particles). Nonlinear estimation is used to fit bimodal distribution, and the general equation is subjected to the frequency distribution of atmospheric aerosols.