毛竹林挥发性有机化合物释放特征及其与环境因子的关系

Characteristics of volatile organic compounds release in Phyllostachys edulis forests and their relationship with environmental factors

【目的】了解毛竹Phyllostachysedulis林内挥发性有机化合物(VOCs)的季节动态变化以及日变化规律,并分析各环境因子对其VOCs摩尔分数变化的影响。【方法】采用吸附管富集采样与气相色谱-质谱联用技术(GC-MS)测定浙江省绍兴市诸暨五泄景区中毛竹林内VOCs成分,分析其变化规律,并结合环境气象监测站数据,分析VOCs摩尔分数与各环境因子的相关性。【结果】①在毛竹林检测出多种物质,主要为烷类、萜烯类、芳香烃类、酯类、醇类和酮类共6类,萜烯类摩尔分数最大,为7.249 nmol·mol^(-1),其中又以组分异戊二烯为主,约占萜烯类的80%。②从季节变化来看,总VOCs摩尔分数在夏季最大,为10.600 nmol·mol^(-1);其次为春季和秋季,分别为8.068和7.254 nmol·mol^(-1);冬季最小,仅为4.432 nmol·mol^(-1),且各类主要VOCs的季节变化趋势与总VOCs相同。③从日变化来看,在春季总VOCs摩尔分数在上午最大,为9.074 nmol·mol^(-1),其次为中午,为8.621 nmol·mol^(-1),下午时段最小,为6.509 nmol·mol^(-1);在夏季、秋季和冬季,总VOCs摩尔分数均在中午最大,分别为11.710、8.038和5.298 nmol·mol^(-1),下午最小,分别为8.455、5.702和3.418 nmol·mol^(-1)。各类主要VOCs的日变化趋势与总VOCs相同,均为上午和中午时段摩尔分数较大。④VOCs与各环境因子都存在相关性,其中萜烯类、烷类、酯类和总VOCs与气温呈显著正相关(P<0.05),与细颗粒物(PM_(2.5))、可吸入颗粒物(PM_(10))和臭氧呈显著负相关(P<0.05)。【结论】在不同季节和时段,毛竹林VOCs种类和摩尔分数不同,其中异戊二烯是决定毛竹林VOCs动态变化的主要物质。

[Objective]The aim is to understand the seasonal dynamics and daily variation patterns of volatile organic compounds(VOCs)in Phyllostachys edulis forest,and analyze the influence of environmental factors on their concentration changes.[Method]The VOCs in Ph.edulis forest in Zhuji Wuxie scenic area,Shaoxing City of Zhejiang Province were determined by sorbent tube enrichment sampling and gas chromatography-mass spectrometry(GC-MS).Its variation pattern was analyzed and the correlation between VOCs concentration and various environmental factors was also analyzed based on the data from environmental meteorological monitoring stations.[Result](1)A variety of substances were detected in Ph.edulis forest,mainly including alkanes,terpenes,aromatic hydrocarbons,esters,alcohols and ketones.The largest concentration of terpenes was released,with a maximum of 7.249 nmol·mol^(-1),of which the dominant component was isoprene,accounting for about 80%of terpene.(2)From the perspective of seasonal variation,the concentration of total VOCs was the largest in summer(10.600 nmol·mol^(-1)),followed by spring and autumn(8.068 and 7.254 nmol·mol^(-1),respectively).The smallest was in winter,only 4.432 nmol·mol^(-1),and the seasonal variation trend of various major VOCs was the same as that of total VOCs.(3)From the perspective of daily variation,the total VOCs concentration was maximum in the morning in spring(9.074 nmol·mol^(-1)),followed by 8.621 nmol·mol^(-1)at noon and a minimum of 6.509 nmol·mol^(-1)in the afternoon.In summer,autumn and winter,the maximum VOCs concentration at noon was 11.710,8.038 and 5.298 nmol·mol^(-1),and the lowest values in the afternoon were 8.455,5.702 and 3.418 nmol·mol^(-1).The daily variation trend of various major VOCs were the same as that of total VOCs,with higher concentrations in the morning and at noon.(4)VOCs were correlated with various environmental factors,among which terpenes,alkanes,esters and total VOCs were significantly positively correlated with temperature,and significantly negatively correlated with PM_(2.5),PM_(10) and ozone(P<0.05).[Conclusion]The types and contents of VOCs in Ph.edulis forest are different in different seasons and time periods,and isoprene is the main substance that determines the dynamics of VOCs.