| Negative air ions which is called"air vitamin"is of advantage to man's health.Its concentration has been an important index in evaluating cleanness of the area air.With the accelerating of forest tourism, forest negative air ions become a research focus in the world.The study took a synchronous monitoring on air anions and several environmental factors such as temperature,relative humidity,sunlight intensity,PM10 and wind speed in different forest communities of nature reserve of Mountain Tianmu,the observations on the air anions and environmental factors in different functional zones (Masson Pines,teaching Area and urban Central District)of Lin'an City were also taken.The temporal change pattern of negative air ions in natural reserve were discussed under the different tourism disturbance,according to the variation of altitude,a contrasting evaluation on the spatial differences of the concentration of negative air ions in different forest communities (Phyllostachys pubescens community, Cryptomeria fortunei community and Phoebe sheareri community) of nature reserve of Mountain Tianmu and the suburb and outer suburb of Lin'an city was taken;besides, in order to probe into influencing contribution rate of several environmental factors to negative air ions,the gray sequence between negative air ions and several environmental factors were also made.The results showed that①The daytime change pattern of the negative air ions and the CI index of Phyllostachys pubescens community and Cryptomeria fortunei community were basically similar in different measuring points under the different tourism disturbance.The peaks of the negative air ions in two measuring points of Phyllostachys pubescens community both appeared at 10:00,the average concentration of negative air ions in Liuchunwu was significantly higher than that of Tianmu hotel at am because of the less disturbance of tourism activities,the daytime change pattern of negative air ions in Liuchunwu presented higher in morning and at night and lower at noon, while the minimum of negative air ions in Tianmu hotel appeared at morning,noon and night.The daytime change pattern of negative air ions in two measuring points of the Cryptomeria fortunei community also showed certain regularity,the average concentration of negative air ions in Wushitongtang was significantly lower than that of Simianfeng during 8:00～15:00 because of greater disturbance of tourism,the minimum of negative air ions in Wushitongtang appeared at 13:00,while the maximum appeared at 16:00;two peaks appeared at 11:00 and 14:00 respectively at daytime in Simianfeng, while the vale value appeared at 12:00.The average negative air ions concentration and CI index of Phyllostachys pubescens community and Cryptomeria fortunei community in different seasonal typical climatic day were both highest in summer,and lowest in winter and less high in autumn.The order of air cleanness in different seasons was:Liuchunwu>Tianmu hotel.The average negative air ions concentration and the air cleanness in Wushitongtang were significantly lower than that of Simianfeng in summer, while higher than that of Simianfeng in autumn and winter.②Based on the variation of altitude,the order of the differences of the average negative air ions concentration and the air cleanness among different Cryptomeria fortunei communities was:Yiliting>Simianfeng >Zhuxiang hotel.③The spatial distribution of negative air ions concentration in different forest communities was of significant difference.The average negative air ions concentration of Phoebe sheareri community in different seasonal typical climatic day were higher than that of Phyllostachys pubescens community and Cryptomeria fortunei community.④As being far from the influence of human activities and the increasing of vegetation coverage,negative air ions concentration increased continuously from lower altitude habitats to higher altitude habitats in suburb and outer suburb of Lin'an city.⑤The most important factors affecting negative Air ions in different functional zones of Lin'an City were air temperature and air relative humidity. |
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