Abstract: The natural sedimentation method was employed to monitor airborne microbial concentration of different functional areas in Tianjin EconomicTechnological Development Area (TEDA, Tianjin) from March 2012 to February 2013. The results showed that bacteria were predominant (76.5%), followed by fungi (19.4%) and actinomyces (4.1%). Canonical ordination analysis was performed to elucidate the temporal and spatial distribution of urban airborne microbes. The results indicated that microbes had a dramatically spatial cluster based on urban function (five types of clusters), among which 46.0% of variation could be explained by first and second axis, with the highest microbial concentration in constructing and industrial area and the lowest in residence zone; on the other hand, microbes had a remarkable temporal cluster according to seasons (three clusters), in which 78.7% of variation could be interpreted by first and second axis with the highest microbial concentration in summer and the lowest in winter. Airborne microbial concentration had a significant positive correlation with temperature (P<0.01). The study showed that airborne microbial variation in temporal distribution was higher than that in spatial distribution, illustrating that the effect of seasonality was stronger than that of area function. In addition, the results revealed that PM₁₀ concentration was positively correlated to SO₂ concentration (P=0.011) in TEDA, Tianjin, suggesting SO₂type smog in this area.

Key words: plant community, environmental factor., Miao Archipelago, functional diversity, species diversity, structural diversity