Assessment of Inhalation Exposures to Indoor and Occupational Aerosols

室内和职业气雾剂暴露评估-共识报告确定了暴露在潮湿的室内环境、微生物生长和不利的呼吸道健康影响之间的联系。在这些潮湿的污染环境中发现的真菌生物气雾剂的吸入暴露仍然是公众非常关注的一个领域，特别是对于在自然灾害或洪水事件后居住在这些受水破坏的环境中或返回这些受水损害的环境的居民。为了评估暴露的风险，制定标准的暴露评估方法以确定和量化微生物生物气溶胶，以确定暴露的来源、代谢副产物和生物标志物是至关重要的。在前几年进行的研究的基础上，NIOSH在2020财年继续进行项目，以更好地了解真菌暴露造成的不良健康影响。以前进行的基于测序的研究已经确定真菌酵母菌是个人暴露的来源，而真菌酵母经常被忽视。担子菌酵母菌在室内污染环境中占主导地位，但它们在有害健康影响中的作用相对来说还不清楚。为了解决这一知识差距，开发了物种特异的引物、探针和定量聚合酶链式反应(QPCR)方法来检测和定量维氏粘菌(Vishniaczyma Victoriae)。维氏隐球菌)。然后，这种物种特异性的qPCR方法被用于检测和定量来自参与纽约市邻里哮喘和过敏研究(NAAS)的家庭的灰尘样本中的维多利亚弧菌。此外，在纽约大都会地区哮喘患病率低和高患病率社区的儿童家庭中，研究了住房因素和与维多利亚弧菌暴露相关的健康影响。这项研究的结果将为真菌酵母菌暴露和呼吸道疾病之间的联系提供新的见解。除了接触包括孢子、菌丝和亚微米碎片在内的真菌成分外，接触真菌还包括真菌代谢的次要副产品，如真菌毒素。在2020财年，《职业与环境卫生杂志》发表了一篇题为《储存温度和储存时间对27种真菌次生代谢物浓度的影响》的手稿。这篇手稿报道，地板尘埃中的真菌次生代谢物，包括真菌毒素，在室温下迅速降解，而在冷藏或冷冻条件下储存会减缓降解。研究表明，贮藏温度比贮藏时间对代谢产物降解的影响更大。次生代谢物在室温下的快速降解可能表明，这些代谢物，特别是真菌毒素，在室内尘埃中的浓度可能很低。NIOSH以前曾记录过与使用高通量高效液相色谱-串联质谱仪方法对粉尘样品中的代谢物进行量化有关的大量基质效应。在2020财年，进一步研究了一种补偿大量基质效应的标准添加方法。目前，正在通过比较使用内标物和没有内标物的次生代谢物浓度来检验在分析地板粉尘样品中多种真菌代谢物时使用内标物的重要性。除了检查次生代谢物的储存条件外，在2020财年还完成了评估标准物质在多种储存条件下延长储存时间期间稳定性的实验。通过对来自50所学校的500份粉尘样本的真菌DNA序列分析，分别从48.1%和83.4%的样本中鉴定出禾谷镰刀菌和镰刀菌以及真菌毒素--脱氧雪腐镰刀菌醇。21财年将继续对地板粉尘样本的真菌次生代谢物进行检查。

Exposure Assessment of Indoor and Occupational Aerosols - Consensus reports have identified associations between exposure to damp indoor environments, microbial growth and adverse respiratory health effects. Inhalation exposure of fungal bioaerosols found within these damp contaminated environments continues to be an area of great public concern especially for residents residing in or returning to these water damaged environments following natural disasters or flooding events. To assess the risk of exposure, the development of standard exposure assessment methods to identify and quantify microbial bioaerosols is critical, in order to determine sources, metabolic byproducts and biomarkers of exposure. Building upon the research conducted in previous years, NIOSH continued ongoing projects in FY20 to better understand the adverse health effects caused by fungal exposure. Sequencing-based studies conducted previously have identified fungal yeasts, which are often overlooked, as sources of personal exposure. Basidiomycota yeasts are prominent in indoor contaminated environments, but their role in adverse health effects has remained relatively uncharacterized. To address this knowledge gap, species-specific primers, probes, and a quantitative polymerase chain reaction (qPCR) method were developed to provide the detection and quantification of Vishniacozyma victoriae (syn. Cryptococcus victoriae). This species-specific qPCR assay was then used to detect and quantify V. victoriae in dust samples from homes participating in the New York City Neighborhood Asthma and Allergy Study (NAAS). In addition, the influence of housing factors and health effects associated with V. victoriae exposure in homes of children from low and high asthma prevalence neighborhoods in the New York metropolitan area were examined. The results from this study will provide new insight into the association between fungal yeast exposure and airway diseases. Along with exposure to fungal components including spores, hyphae and submicron fragments, exposure to fungi also includes secondary byproducts of fungal metabolism, such as mycotoxins. In FY20, a manuscript titled “Effect of storage temperature and duration on concentrations of 27 fungal secondary metabolites spiked into floor dust from an office building” was published in the Journal of Occupational and Environmental Hygiene. This manuscript reported that fungal secondary metabolites in floor dust, including mycotoxins, quickly degraded at room temperature, whereas storing them under refrigeration or freezing conditions slowed degradation. This study demonstrated that storage temperature influenced degradation of the metabolites more than storage time. The rapid degradation of the secondary metabolites at room temperature may indicate that the concentrations of those metabolites, especially mycotoxins, are likely to be low in indoor settled dust. NIOSH had previously documented substantial matrix effects associated with the quantification of the metabolites in dust samples using the high-throughput HPLC-MSMS method. A standard addition method to compensate for substantial matrix effects was further investigated in FY20. Currently, the importance of using internal standards in the analysis of multiple fungal metabolites in floor dust samples is being examined by comparing the concentrations of the secondary metabolites measured with internal standards to those without internal standards. In addition to the examination of secondary metabolite storage conditions, experiments to assess stability of standard materials during storage at multiple storage conditions for extended time periods were also completed in FY20. Using the assessment of fungal DNA sequences from 500 dust samples previously collected from 50 schools, the organisms Fusarium graminearum and F. culmorum were identified, along with the mycotoxin, deoxynivalenol, from 48.1% and 83.4% of the samples, respectively. Examination of fungal secondary metabolite profiles for the floor dust samples will continue in FY21.