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.
The research adopts open sampling method and TCT-GC/MS(Thermodesorption Cold Trap-Gas Chromatography/Mass Spectrometery) apparatus to collect and analyze the volatile organic compounds(VOCs) of Platycladus orientalis forest,with the intention of researching the compounds and diurnal variation of VOCs of P.orientalis forest in natural state in Beijing Western Hills in spring.The results are as follows:(1) There are 160 kinds(11 categories) of volatile organic compounds,containing Alkyl Hydrocarbon,Ketone,Alcohol,Acid,Aldehyde,Alkene,Ester,Aromatic hydrocarbon,Ether,Hydroxybenzene and Amide.The content of Alkyl Hydrocarbon,Ketone,Acid and Aldehyde occupy a greater percentage among all compounds.(2) The diurnal variation curve of total volatile organic compounds(TVOC) is characterized as "one peak at 11:00(36.44%) and one vale at 3:00(12.76%)".Generally,the concentration at daytime is higher than that of night,and higher in morning than in afternoon,with the maximum at noon.(3) The change of Alkyl Hydrocarbon concentration is greater in the morning and about midday,less in the afternoon and night.The diurnal variation curve of Ketone concentration appears as "three peaks and three vales".1:00,5:00—7:00 and 11:00 are peak time,3:00,9:00 and 17:00 are vale time.As to Acid,its concentration appears two obvious phases: the higher phase is from 9:00 to 17:00,with the maximum at 11:00,and the lower phase is from 19:00 to 7:00,with the minimum at 5:00.Concerning Aldehyde concentration,17:00 and 19:00 are the higher phases and also has obvious difference with other time,while the lower phrase has no obvious difference with each other.(4) Alkene is the most important compound to human health.Its concentration appears as "one peak" at 15:00,which has obvious difference with other time.Totally,its content at daytime is higher than that at night,and higher in afternoon than in morning.
