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柴油机尾气中的微粒粒径大小分布范围广泛,不同直径的微粒所占的比例以及对环境和人身健康造成的危害各不相同,因此对微粒粒径特征进行研究更具有实际意义。本研究分别采用滤膜称重法和光散射法对厦工XG951Ⅲ装载机配置的国Ⅲ柴油发动机怠速工况下的尾气进行测试,研究了微粒的质量浓度分布、数量浓度分布以及质量浓度与数量浓度分布的关系。研究结果表明,从微粒质量上看,可吸入微粒(PM10)占微粒总量(TSP)的74.0%,可入肺微粒(PM2.5)占可吸入微粒的48.1%;2.5μm以下粒径范围内的微粒质量浓度是2.5~10μm粒径范围内微粒质量浓度的将近3倍,是10~100μm粒径范围内微粒质量浓度的52倍;2.5~10μm粒径范围的微粒质量浓度是10~100μm粒径范围内微粒质量浓度的18倍。数量上,在不同的数量级上,微粒数量浓度随粒径变化差距很明显,尤其是1μm以下的微粒较多。另外,质量浓度的粒径分布滞后于数量浓度。因此PM2.5排放标准中应考虑以个数浓度代替质量浓度为标准。
Diesel exhaust particle size distribution in a wide range of sizes, the proportion of different diameters of particles and the harm to the environment and human health are not the same, so the study of particle size characteristics of more practical significance. In this study, exhaust gas under idle condition of State Ⅲ diesel engine equipped with XG951 Ⅲ loader for Xiamen Engineering was measured by the method of filter membrane weighing and light scattering. The effects of mass concentration distribution, quantity concentration distribution and mass concentration and concentration Distribution of relations. The results showed that PM10 accounted for 74.0% of total particulate (TSP) and PM2.5 accounted for 48.1% of inhalable particulates in terms of particle quality. In the range of particle size below 2.5 μm Within the particle size range of 2.5 ~ 10μm particle concentration of nearly 3 times the particle size range of 10 ~ 100μm particle concentration of 52 times the mass; particle size range of 2.5 ~ 10μm particle concentration is 10 ~ 100μm Particle size within 18 times the mass concentration of particles. Quantitatively, on different orders of magnitude, the difference of particle number concentration with particle size is obvious, especially the particles under 1μm are more. In addition, the particle size distribution of the mass concentration lags behind the concentration. Therefore, PM2.5 emission standards should be considered in place of the number of concentrations of concentration as a standard.