Negative air ion concentration and affecting factors in Beijing Olympic Forest Park.

In this study, sampling plots and control were chosen in the Beijing Olympic Forest Park(BOFP) and negative air ion(NAI) concentrations were measured continually in clear days of August 18--20, 2009. The results indicated that the effect of plant community structure on NAI was significantly different. NAI concentration of the tree-shrub-grass communities was higher than that in the simple plant communities, especially higher than that in the single-layer ones. The correlation between multiple plant communities and NAI concentration was significant. Moreover, NAI concentration of the deciduous broad-leaved forest regions was higher than those of the coniferous forest and mixed conifer and broad-leaved one. The results showed that there was positive correlations between NAI concentration and air relative humidity and air temperature.