Font Size: a A A

Analysis On Volatile Organic Compounds Of Four Species Of Trees And Effects On SOA

Posted on:2017-03-18Degree:MasterType:Thesis
Country:ChinaCandidate:J ChenFull Text:PDF
GTID:2283330485963190Subject:Soil and Water Conservation and Desertification Control
Abstract/Summary:PDF Full Text Request
Volatile organic compounds (VOCs) have significant impact on human health, atmospheric environment and air quality. In this study, Pinus tabuliformis、Platycladus orientalis、Quercus variabilis Blume and Acer mono Maxim. in artificial mixture plantation in Jiufeng National Forest Park were chosen as research object. The research adopted living plants dynamic headspace method to collect VOCs in sunny wireless days in July、October,2014 and January、April、July,2015, used Thermodesorption Cold Trap-Gas Chromatography Mass Spectrometery apparatus (TCT-GC-MS) and external standard method for qualitative and quantitative analysis. Based on these, the research studied dynamic changes of VOCs and correlation with environmental factors, and estimated the formation potential of secondary organic aerosol (SOA) by using fractional aerosol coefficients (FAC) to provide reference for urban greening.The main conclusions of this article are:(1) Quantity of VOCs:There are 176 kinds of VOCs in leaves of P.tabuliformis, alkene and alkane are more than others; there are 188 kinds of VOCs in leaves of P. orientalis, alkene、alkane and alcohol are more than others; there are 168 kinds of VOCs in leaves of Q.variabilis,alkane、eater and alcohol are more than others; there are 174 kinds of VOCs in leaves of A. mono, alkene, eater and alcohol are more than others. The number of VOCs of conifers is larger than that of hardwoods. Conifers release alkene and and alkane more,while hardwoods release eater and alcohol more.(2) Concentration of VOCs:The concentration of TBVOCs of P.tabuliformis is summer> autumn> spring> winter, P. orientalisis summer> autumn> winter> spring, Q.variabilis and A. mono are both summer> autumn> spring, at the same time, concentration in summer has significant difference with that in other seasons. The concentration of TBVOCs of P.tabuliformis and P. orientalis reach the peak at 11:00-12:00 in summer and autumn, at 13:00-14.00 in spring and winter, the diurnal change of the concentration in four seasons presents unimodal pattern individually; the concentration of TBVOCs of Q.variabilis reaches the peak at 11.00-12:00 and 13:00-14:00 in spring,11:00-12:00 and 15:00-16:00 in summer,11:00-12:00 in autumn, the diurnal change of the concentration in spring and summer presents bimodal pattern and in autumn presents unimodal pattern; the concentration of TBVOCs of A. mono reaches the peak at 13:00-14:00 in spring, at 11:00-12:00 in summer and autumn, the diurnal change of concentration in three seasons presents unimodal pattern individually.(3) Component of VOCs:alkene released by P.tabuliformis occupies over 80% of TBVOCs,α-pinene, limonene,β-myrcene, a-farnesene and caryophyllene has high content, other kinds of VOCs were little; alkene released by P. orientalis occupies about 55% of TBVOCs, a-pinene, limonene,β-myrcene, β-pinenecan reach up to about 10% of TBVOCs, alkanes can account for about 10% of TBVOCs that cycloheptane and hendecane have high content;alkanes and ester released by Q.variabilis occupy 15% and 10% of TBVOCs individually, except for monoterpenes and sesquiterpenes, Q.variabilis also releases large amount of isoprene, which can occupy the highest content 11.642%; alkene and ester released by A. mono occupy 40% and 20% of TBVOCs individually, isoprene can account for the highest content 19.720%.(4) Volatile secondary organic aerosols:The mean volatile SOA concentration in the atmosphere is 1.879μg/m3 in spring,6.864μg/m3 in summer,3.017μg/m3 in autumn, and 1.104μg/m3 in winter. The volatile SOA concentration of P. tabulaeformis in four seasons is 17.884μg/m3,92.105μg/m3, 61.553μg/m3,4.822μg/m3 individually; P.orientalis is 9.847μg/m3,71.624μg/m3,27.003μg/m3, 9.208μg/m3 individually; Q.variabilisis 1.250μg/m3,29.378μg/m3,14.037μg/m3 individually; A. mono is 1.166μg/m3,31.537μg/m3,11.564μg/m3 individually. BVOCs can increase the concentration of SOA, and further increase the concentration of PM2.5, which will affect the atmospheric environment.
Keywords/Search Tags:Volatile organic compounds, quantity, concentration, environmental factors, secondary organic aerosols
PDF Full Text Request
Related items