城市绿地空气细菌含量变化特征

Change of Airborne Bacteria Content in Different Type of Urban Greenland

为了了解城市绿地空气细菌含量的时空变化情况以及不同空间结构绿地减菌作用的差异,通过对北京市元大都公园内全年监测样地和不同空间结构样地空气细菌的测定,得出了城市绿地空气细菌含量的年变化基本上呈双峰曲线,11月和5月含量较高,其它月份相对较低,而且证明在植物生长季绿地减菌能力较强。城市绿地空气细菌含量秋季、春季、夏季的日变化各不相同,秋季8:00~14:00总体呈下降趋势,14:00~16:00略有升高,而16:00~18:00大部分绿地有所下降;春季7:00~13:00下降,13:00~19:00呈上升趋势;夏季在9:00和17:00出现峰值,基本呈双峰型。不同空间结构的绿地减菌作用不同,春季针叶乔木具有优势,夏季阔叶乔木表现优秀,而草坪最差。在城市绿化建设中,如果从降低空气细菌含量方面考虑,建议建设绿地面积最好>900 m2,如果达不到900m2,可以考虑建设面积至少>400 m2。

In this paper,the spatio-temporal change of airborne bacteria content in different types of urban greenland and the bacteria-reducing effect in different structure greenland were explored.In Beijing Yuan Dynasty capital city wall relics park,by monitoring nine plots and analyzing airborne bacteria content in the different structure greenland,it could be concluded that annual dynamics of airborne bacteria content in the different types of urban greenland presented double-peak curve which was relatively higher at the November and May than other month.At the same time,it was testified that the plants in growth season had the higher bacteria-reducing ability.The daily change of airborne bacteria content in the different types of urban greenland was different in autumn,spring and summer:The airborne bacteria content was on the decline trend at 8:00 to 14:00 and appreciable increase at 14:00～16:00 in autumn,decrease at 7:00～13:00 and increase at 13:00～19:00 in spring,presented double-peak curve which was at the(9:00) and 17:00 in summer.There was different bacteria-reducing ability in different structure greenland,among which the needle arbor has the superiority in spring,and the broadleaved arbor had the predominance in summer whereas the lawn had the lowest ability to reduce bacteria content.In the construction of urban forest,it was suggested that the best area of greenland should be over 900 m^2 on the aspect of reducing airborne bacteria content.The greenland area could be over 400 m^2 when the best index was unacceptable.