西安市春季生物气溶胶的分布特征和健康影响

西安春季经常出现大量飞絮，易造成空气污染并引发居民哮喘等健康风险.采集西安市春季不同观测点(交通样点和校园样点)生物气溶胶、 PM_2.5和飞絮样品，通过恒温培养和高通量测序等方法研究可培养生物气溶胶的浓度变化、粒径分布，PM_2.5和飞絮携带的微生物的来源、群落结构和健康影响.结果表明，可培养细菌浓度在交通样点高于校园样点(P=0.027);交通样点可培养细菌浓度为真菌的2.7倍，而校园样点可培养真菌浓度高于细菌(1.4倍).可培养细菌和真菌日内最高浓度均出现在08:00;可培养细菌粒径呈双峰分布，真菌为单峰分布.土壤和植被是大气微生物的主要来源(占比85.9%),变形菌门(Proteobacteria)是飞絮和PM_2.5中共有的、丰度最高的菌门，在飞絮中占比达到91.3%(交通样点)和99.1%(校园样点);在PM_2.5样品中放线菌门(Actinobacteria)、厚壁菌门(Firmicutes)、拟杆菌门(Bacteroidetes)、蓝藻门(Cyanobacteria)和异常球菌-栖热菌门(D...

Distribution Characteristics and Health Effects of Bioaerosols in Spring over Xi'an City

A large amount of fluffy caktins appears in spring in Xi''an that may cause air pollution and lead to health risks such as asthma. In this study, bioaerosol, PM_2.5, and fluffy catkins were collected from different sample points (traffic site and campus site) in Xi''an in spring. The variations in bioaerosol, fluffy catkins, and the bacterial community structure were investigated using culture-dependent and high-throughput sequencing methods. The results showed that the concentration of culturable bacteria was significantly higher (P=0.027) at the traffic site. The concentration of culturable bacteria at the traffic site was 2.7 times that of fungi, whereas the concentration of culturable fungi at the campus site was 1.4 times higher than that of bacteria. The peak concentrations of culturable bacteria and fungi appeared at 08:00 a.m. The size distribution of culturable bacteria showed a bimodal pattern, whereas that of culturable fungi showed a unimodal distribution. Soil and vegetation were the main sources of atmospheric microorganisms (85.9%), and Proteobacteria was the most abundant phylum in both fluffy catkins and PM_2.5, accounting for 91.3% (traffic site) and 99.1% (campus site) of the fluffy catkins. Actinobacteria, Firmicutes, Bacteroidetes, Cyanobacteria, and Deinococcus-Thermus were the dominant phyla in PM_2.5. Some genera were opportunistic pathogen bacteria in the fluffy catkins, such as Enterobacter and Pseudomonas, which can lead to infection and diarrhea risks. These results could provide fundamental data on potential health risks of spring-borne bioaerosols.