浙北地区真菌气溶胶示踪物季节分布特征

Seasonal variation characteristics of fungi aerosol tracers in the northern Zhejiang Province

于2014年12月—2015年11月收集了浙江北部地区4个采样点的PM2.5样品,利用高效液相色谱-串联质谱仪分析获得真菌气溶胶示踪物阿糖醇和甘露醇的浓度,研究了浙北地区真菌气溶胶的季节性变化特征及其来源.观测结果显示,浙北地区阿糖醇和甘露醇的年均浓度分别为(5.6±0.7)和(5.7±1.3)ng·m-3.真菌气溶胶示踪物夏季浓度最高,可能是由于当地夏季频繁的生物质燃烧和温暖湿润的气候条件促进了真菌孢子的释放;另外,在该地区真菌孢子对气溶胶中有机碳(OC)的贡献并不显著(<1%).主成分分析显示,真菌气溶胶示踪物(阿糖醇、甘露醇)和生物质燃烧示踪物(左旋葡聚糖、甘露聚糖、半乳聚糖、nss-K+)在整个采样过程中都包含在同一个因子中,表明浙北地区大气中真菌气溶胶持续受到生物质燃烧排放源的影响.

One year-long PM2.5 field sampling was conducted at four representative sites in the northern Zhejiang Province（ NZP） from December 2014 to November 2015. Fungi aerosol tracers such as arabitol and mannitol have been measured by using high performance liquid chromatography（ HPLC）-triple quadrupole tandem mass spectrometry（ MS/MS）. Seasonal variation characteristics and sources of fungal aerosol tracers in NZP area were investigated.The annual averaged concentrations of arabitol and mannitol in NZP were（ 5.6±0.7） and（ 5.7±1.3） ng·m^-3,respectively. The elevated fungal aerosol tracers in summer could be attributed to the intensive local biomass burning and effect of wet and warm weather conditions favorable for the release of fungal spores. The contributions of fungal spores to the organic carbon（ OC）,estimated using mannitol-based conversion factor,were below 1% at all sampling sites. The results from principle component analysis（ PCA） also showed that fungal spore tracers（ arabitol,mannitol） and biomass burning tracers（ levoglucosan,mannosan,galactosan,nss-K＋） were mostly grouped within the same component contributing to PM2.5 mass during the whole sampling campaign,indicating a continuous influence from biomass burning to the airborne fungal spores in NZP.