Respiratory Protection Against Bioaerosols in Agriculture

描述（由申请人提供）：农业工人经常暴露于高浓度的空气微生物中，患呼吸道疾病的风险增加。目前，对农业工人使用的呼吸器的有效性知之甚少，特别是对空气中微生物的有效性。在最初的拨款中，我们开发了一种新的方法来测量N95过滤式口罩对生物和非生物颗粒的工作场所保护系数（WPF）。我们的中试现场研究显示了颗粒大小和颗粒类型对WPF的影响。随着粒径的减小，WPF在0.3 ~ 10瓮范围内降低。令人惊讶的是，对生物颗粒的wpf值比对相同尺寸范围内所有尘埃颗粒的wpf值低2-6倍。拟议的续编的第一个目的是建立一个关于生物粒子和尘埃的世界气象论坛的综合实地数据库。每位受试者（25名农民或农业工人）将使用两种呼吸器模型（一种N-95过滤面罩和一种弹性半面罩）重复WPF测试。该研究将提供关于实际野外环境中不同特征粒子的wpf范围的独特新数据。第二个目的是通过基于人体模型的调查和理论建模来研究颗粒特性对其进入呼吸器的影响。来自三个选定农场的颗粒将根据其空气动力学大小，形状和微生物组成进行特征分析。进行这种测试是为了选择非生物测试颗粒，并分离真菌和细菌以供进一步的实验室测试。呼吸器的性能将通过基于人体模型的实验室测试来比较不同特征的颗粒。最后，基于人体模型的测试将在三个选定的农场进行，以确保真实的气溶胶特性和成分。现场和实验室数据以及理论模型的结合将提供急需的通用信息，以完善防毒面具使用指南并设计更高效的防毒面具。这些信息也可用于需要呼吸防护的其他工作环境，如发霉的建筑物、卫生保健机构和受生物恐怖主义影响的地区。该提案与NIOSH的使命完全一致，因为研究结果将通过研究、信息和防护口罩培训，帮助农业工人确保安全和健康的工作条件。

DESCRIPTION (provided by applicant): Agricultural workers are often exposed to high concentrations of airborne microorganisms and at increased risk for developing respiratory diseases. Currently, little is known regarding the effectiveness of respirators used by agricultural workers especially with respect to airborne microorganisms. In the original grant, we developed a new method to measure workplace protection factors (WPF) of N95 filtering facepiece respirators against biological and non-biological particles. Our pilot-scale field study showed intriguing results on the effect of particle size and particle type on the WPF. Decreasing particle size decreased the WPF in a size range of 0.3 to 10 urn. Surprisingly, WPF-values against biological particles were 2-6 times lower than those measured for all dust particles in the same size range. The first aim of the proposed continuation is to generate a comprehensive field database on the WPF against biological particles and dust. Each subject (25 farmers or agricultural workers) will repeat WPF testing with two respirator models (one N-95 filtering facepiece and one elastomeric half-facepiece). The study will provide unique new data on the range of WPFs against particles of different characteristics in real field settings. The second aim is to investigate the effect of particle characteristics on their penetration into the respirator by manikin-based investigation and theoretical modeling. Particles from three selected farms will be characterized in regards to their aerodynamic size, shape, and microbiological composition. This testing is performed to select non-biological test particles and to isolate fungi and bacteria for further laboratory testing. Respirator performance will be compared for particles of different characteristics by manikin-based laboratory testing. Finally, manikin-based testing will be performed at three selected farms to assure realistic aerosol characteristics and composition. The combination of field and laboratory-based data and theoretical modeling will provide much-needed generalizable information to refine the guidelines on respirator use and to design more efficient respirators. This information can also be utilized for other work environments in which the respiratory protection is needed, such as moldy buildings, health care settings, and areas affected by bioterrorism. This proposal is well in line with NIOSH mission as the study outcome will help assure safe and healthful working conditions for agricultural workers through research, information, and training on respirators.