室外空气细菌群落特征研究进展

ADVANCE IN CHARACTERISTICS OF AIRBORNE BACTERIA COMMUNITIES IN OUTDOOR ENVIRONMENT

着重论述了空气细菌的来源、粒子特征、群落特征、浓度的时空变化及其群落结构的影响因素.国内外研究结果表明:空气细菌主要来源于自然界的土壤、动植物、人类和水体,另外一些非自然的人类活动也是其重要来源;空气细菌的粒径主要在0.3～15.0 μm间变化,海岸边细菌气溶胶的粒径相对较小,而其他地方84%或更多的细菌粒子的粒径≥2.1 μm;空气中革兰氏阳性细菌占绝大多数,无论在森林、海岸、城市还是乡村,芽孢杆菌(Bacillus)都是优势菌属;一年中空气细菌浓度夏季最高,冬季最低,一天中则可以明显的划分为5个阶段:(ⅰ)午夜细菌浓度最低,(ⅱ)日出时细菌浓度达到高峰,(ⅲ)正午细菌浓度积累逐渐上升,(ⅳ)下午后期细菌浓度降低,(ⅴ)晚上到午夜细菌浓度较低;人类活动频繁,动植物较多的地方空气细菌浓度较高.此外,空气细菌不仅与各种环境因素有关,还受到各种污染因子的影响. 表2

The review focuses on the progresses of airborne bacteria in outdoor environment, including their sources, particle and community characteristics, space-time fluctuation of concentration and influence factors of community structure. The research prospects of outdoor airborne bacteria were also discussed. It is suggested that soil, animal, vegetation, human being and water body are the main sources, and other unnatural human activities are also the important factors. The particle diameter ranges from 0.3 μm to 15 μm, and in coastal areas it is smaller than that of other areas, where more than 84% bacteria particles are larger than 2.1 μm. Generally speaking, gram-positive bacteria are much more than gram-negative bacteria in the air. In forests, coastal areas, cities and villages, Bacillus is the main genus of bacteria. The concentration reaches lowest in winter, while highest in summer in a year. The diurnal distribution of bacteria in the atmosphere can be divided into five periods: (ⅰ) the night-time minimum concentration (23:00 to 06:00), (ⅱ) the sunrise peak concentration (06:00 to 08:00), (ⅲ) the midday accumulating concentration (08:00 to 15:15), (ⅳ) the later afternoon lower concentration (15:15 to 17:00), and (ⅴ) the evening decrease to the night-time minimum concentration(17:00 to 23:00). In the areas with more human activities, animals and vegetations, the concentration of the airborne bacteria is high,and the bacteria are affected not only by environmental factors, but also by pollution factors. Tab 3, Ref 53