基于荧光信号的海陆源生物气溶胶特征研究

Study on Characteristics of Sea-land Distribution Bio-aerosols Based on Fluorescence Signals

生物气溶胶是悬浮在大气中直接来源于生物有机体的粒子,基于生物材料存在荧光的特性利用紫外诱导荧光技术对其监测是近年来的热门研究方法。该研究利用双波段荧光生物气溶胶(WIBS)分别以深圳南澳和韶关南岭监测点作为海陆源背景点进行了大气在线观测,得到了海陆源生物气溶胶特征。深圳南澳3个通道FL1、FL2和FL3的荧光粒子数浓度是0.067、0.067和0.057 cm^(-3),韶关南岭3个通道FL1、FL2和FL3的荧光粒子数浓度是0.012、0.032和0.016 cm^(-3)。进一步根据不同通道荧光阈值将粒子分为7种类型,深圳南澳总荧光气溶胶浓度是0.106 cm^(-3),其中主要是Type ABC和Type A。韶关南岭总荧光粒子浓度为0.053 cm^(-3),其中主要是Type B和Type AC。深圳南澳生物气溶胶的粒径分布在>2μm分布显著,韶关南岭点粒径分布主要集中在1~3μm。利用黑碳、乙腈和m/z44与不同类型荧光粒子的相关分析,得到深圳南澳和韶关南岭受到非生物性成分的影响较小,能较好地代表海陆源生物气溶胶。进一步比较海陆源和深圳15 a夏季荧光粒子的粒径特征,通过PMF模型运算,得到海洋源生物气溶胶对深圳夏季生物气溶胶的贡献有0.020 cm^(-3),占到总荧光粒子的2.9%。

Bio-aerosols,suspended in the atmosphere,are the particles directly from biological organism.According to the biological fluorophores property existed in the organic materials,the method to utilize UV laser-induced fluorescence technology for detecting the airborne particles has become a hot-topic research in recent days.In this paper,a wideband integrated bioaerosol spectrometer（WIBS）was used to online monitor the atmosphere at a sea sampling site at Nan’ao of Shenzhen City,in addition,a land sampling site in Nanling of Shaoguan City for the purpose of obtaining the characteristics of bio-aerosols.The monitoring suggested that the average number concentrations（number of the particles）in the three channels：FL1,FL2 and FL3 were 0.067,0.067 and 0.057 cm-3,respectively at Nan’ao;and the average number concentrations in the three channels：FL1,FL2 and FL3 were 0.012,0.032 and 0.016 cm-3respectively at Nanling.Furthermore,as the fluorescent particles were divided into seven types according to the fluorescence threshold,the concentration of total bio-aerosols at Nan’ao was 0.106cm-3,among others,the most abundant species were Types ABC and A.The number concentration of total bio-aerosols at Nanling reached 0.053 cm-3,the most abundant species were Types B and AC.The size distribution of biological aerosol was observed as well,the result indicated the size distribution was bigger than 2μm at Nan’ao,while ranging from 1～3μm at Nanling.Results of the correlation analysis of black carbon,acetonitrile and m/z 44 with different types of fluorescent particles indicated that fluorescence particles at both of Nan’ao and Nanling well represented the sea-land bio-aerosols;furthermore,particles size distribution of sea-land bio-aerosols during summer was compared,and through simulation computation using the PMF model it was obtained that the sea source bio-aerosols contribution to Shenzhen City in summer was 0.020 cm-3,accounting for 2.9%of total fluorescence particles.