The Change Regularity Of Particulate Matter Concentration And Dry Deposition In Different Surface

Inhalable particles especially dynamic diameter ?2.5 um has become a serious air pollution problem around majority cities.Wetland and forest had a great influence on the particle concentration and dry deposition.In order to study the regulation of wetland and forest,we implemented a study to measure the PM concentration and chemical composition at three heights in the Olympic Park and to quantify the atmospheric particulate dry deposition velocity and dry deposition flux,and then using the Bayes model to build the particulate matter blocking in wetland and forest.Results indicated that:(1)The diurnal variations of the PM2.5 and PM10 concentrations in wetland and forest had a"V" tendency in that the highest occurred in the morning and night and the lowest occurred at noon.The PM2.5 and PM10 concentrations also varied in different seasons.In wetland,the highest concentration of PM10 occurred in winter and the lowest occurred in autumn,which in winter was about 8 times than autumn,the highest concentration of PM2.5 occurred in winter and the lowest occurred in summer,which was about 16 times than summer.In forest,the highest concentration of PM10 and PM2.5 occurred in winter and the lowest occurred in summer,which was about 9,10 times than summer,respectively.In wetland,PM10 and PM2.5 concentration had a significant difference at different heights,while the difference in forest was not.The PM2.5 and PM10 concentration in wetland and forest had a positive relationship with wind speed and a negative relationship with relative humidity and temperature.(2)The ions of PM2.5 in the wetland and forest are Na+,NH4+,K+,Mg25+,Ca2+,SO42-,NO3-,Cl-,HCOO-,F-.The S042-(51.32%),N03-(12.55%),Cl-(12.19%)were main componets in wetlnd,while the main componets in forest were SO42-(48.47%),NO3-(13.75%),NH4+(10.05%),Cl-(10.83%).And the ions had an obvious seasonal variation but the spatial variations was not obvious.(3)In wetland,the PM10 deposition velocity was the highest in winter(0.097±0.066 cm s-1)and the lowest in spring(0.048±0.034 cm s-1),which is 102%higher than spring,the PM2.5 deposition velocity was the highest in winter(0.071±0.046 cm s-1)and the lowest in autumn(0.048±0.034 cm s-1),which is 3 times higher than spring.In the forest,the PM10 deposition velocity was the highest in winter(0.047±0.024 cm s-1)and the lowest in autumn(0.017±0.011 cm S-1),which is 2 times higher than autumn,the PM2.5 deposition velocity was the highest in winter(0.038±0.014 cm s-1)and the lowest in spring(0.021±0.017 cm s-1),which is 80%higher than spring.In wetland,the PM10 and PM2.5 deposition flux were the highest in winter,which were 4.14±6.42 ug m-2 s-1.15±1.81 ug m-2 s-1 and the flux in winter were 20 and 40 times higher than in 4.14+6.42ugm-2s-1,1.15±1.81 ugm-2s-1 and the flux in winter were 20 and 40 tiomes higher than inautumn.In the forest,the PM10 highest deposition flux occurred in spring(0.47±0.22 ug m-2 s-1)and the lowest in autumn,which is 80%higher than in autumn,the PM2.5 highest deposition flux occurred in autumn(0.96±0.13ug m-2 s-1)and the lowest in summer,which is 4 times higher than in summer.(4)Using multi-Bayes method to build the blocking single factor model and yi?N(?0+?1xi,?y2)?v?N(0,?2)and two factors model yi?N(?0+?1x1i+?2x2i,?y2)?y?N(0,?2).