Respiratory Protection Against Bioaerosols in Agriculture

描述(申请人提供)：农业工人经常暴露在高浓度的空气微生物中，患呼吸道疾病的风险增加。目前，人们对农业工人使用的呼吸器的有效性知之甚少，特别是对空气中的微生物。在最初的拨款中，我们开发了一种新的方法来测量N95过滤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关于颗粒大小和颗粒类型对WPF的影响的有趣结果。减小颗粒大小会使WPF在0.3到10微米的范围内减小。令人惊讶的是，针对生物颗粒的WPF-值比对相同尺寸范围内的所有尘埃颗粒测量的WPF-值低2-6倍。拟议延续的第一个目标是建立一个关于防治生物颗粒和粉尘的世界粮食安全论坛的综合实地数据库。每个受试者(25名农民或农业工人)将用两种型号的呼吸器(一个N-95过滤面罩和一个弹性半面口罩)重复WPF测试。这项研究将提供关于在真实场地环境中针对不同特征的颗粒的WPF范围的独特的新数据。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渗透到呼吸器中的影响。来自三个选定农场的颗粒物将根据其空气动力学大小、形状和微生物组成进行表征。进行这项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性的颗粒。最后，将在三个选定的农场进行基于人体模型的测试，以确保真实的气雾剂特性和成分。现场和实验室数据和理论模型的结合将提供急需的概括性信息，以完善关于呼吸器使用的指导方针，并设计更有效的呼吸器。这些信息也可用于其他需要呼吸保护的工作环境，如发霉的建筑、医疗保健设施和受生物恐怖主义影响的区域。这一建议与NIOSH的使命非常一致，因为研究成果将通过研究、信息和呼吸防护口罩培训，帮助确保农业工人的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.