北京市三个功能区空气微生物中值直径及粒径分布特征

Study on median diameters and size distributions of airborne microbes in three functional regions in Beijing

空气中微生物对人类健康的危害除了与微生物的种类和浓度有关外,还与微生物粒子的大小密切相关,并且不同粒径的空气微生物对人们健康影响的作用机理不同。通过定点试验调查,运用国产安德森生物粒子取样器着重研究北京市3个功能区(文教区-中国科学院生态环境研究中心所在区域、交通干线-西直门和公园绿地-北京植物园)空气微生物的中值直径和粒径分布。结果表明,不同功能区空气微生物的粒径分布相同,空气细菌,真菌与放线菌的粒径分布各不相同。空气细菌粒径呈偏态分布,空气真菌呈对数正态分布,空气放线菌的分布特征与空气真菌相反,主要分布在>8.2μm和<2.0μm级中。不同属真菌的粒径分布也不相同,枝孢属、青霉属和曲霉属呈对数正态分布,链格孢属和无孢菌为偏态分布。空气细菌的中值直径明显大于空气真菌和放线菌。交通干线和公园绿地空气细菌和真菌粒子中值直径明显大于文教区,放线菌粒子中值直径交通干线明显高于文教区和公园绿地。空气微生物中值直径在一年各月中没有明显的变化规律。

The effect of airborne microbes on human health not only depended on their compositions （genera and species）, but also on their concentrations and sizes. Moreover, there are different mechanisms of airborne microbes of different sizes with different effects on human health. The size distributions and median diameters were carried out in detail with Andersen sampler in three different functional regions in Beijing. Results showed that there were similar distribution characteristics of airborne microbes in different functional regions, and different distribution characteristics among airborne bacteria, fungi, and actinomycetes. Airborne bacteria were plotted with skew distribution, and airborne fungi with normal logarithmic distribution. The distributions of airborne actinomycetes were completely opposite to the fungal spore. The size distributions of dominant fungi were consistent in different functional regions. Cladosporiurn, Penicilliurn and Aspergillus were recorded with normal logarithmic distribution, the former was most collected in stage3, stage4 and stages （1.0- 6.0μm）, and the later were most in stage4 and stages （1.0- 3. 5μm）. Alternaria and nonsporing were presented with skew distribution, the former was most found in the former three stages （〉3.0μm）, and the later in the former five stages （〉 1.0μm）. The median diameters of airborne bacteria were larger than airborne fungi and actinomycetes. In three functional regions, the largest bacterial diameter was founded in main traffic lines, and airborne fungi in garden green areas. There were no significant variations of microbial median diameters within the one-year of the study.