Questionnaire survey was taken,the plant-caused pollution in 4 typical cities including Beijing,Hefei,Chengdu and Guangzhou was studied.Differences of three kinds of plant-caused pollution such as pollen,flying hair and catkin,and smell between different cities and different people were analyzed.The results are as follows:the plant-caused pollution has obviously regional distribution features.The rate of plant-caused pollution is 5.72% in Beijing,0.59% in Chengdu,2.12% in Hefei and 2.11% in Guangzhou.The order of the number of three kinds of plant-caused pollution allergen is pollen>flying hair and catkin>smell.The allergen caused by pollen and flying hair and catkin gathers largely in March to June.The allergen caused by smell gathers largely in summer.The whole condition of the allergen is female>male,and most of them are 20 to 50 years old.The results provide basis for the further research,and are also helpful for prevention of plant-caused pollution in urban area.
By the means of 3S technology,the landscape of Beijing was divided into 6 primary landscape types and 18 landscape patch types in the study,and a series of indexes were calculated by models to analyze the special structure of Beijing landscape.The results show: that the forest land is the maximal and basal landscape patch type(area proportion is 42.534%),farmland(28.888%)and construction area(16.639%) are also the main landscape types in Beijing.From landscape patch types and landscape patch categories levels,the landscape patch distributon is centralized,and patch shape is simple,the main landscape patch fractal dimension indexes are under 1.1,so urban landscape pattern is highly influenced by human disturbance.
