RAPID: COVID Response: Identifying practices that minimize exposure to disinfection byproducts

为了遏制新冠肺炎的传播，世界各地的社区正在对建筑物和其他公共场所进行消毒。清洁工人戴着不同级别的个人防护，从简单的医用口罩到专业的高效过滤口罩。根据口罩类型、清洁过程、表面和使用的消毒剂，清洁工人可能接触到消毒剂、被清洁表面和口罩材料之间反应形成的消毒副产品。该项目将量化在消毒过程中佩戴不同类别口罩时消毒副产品的吸入情况，并使用这些信息就戴哪种口罩以及更换或清洁口罩或口罩部件的频率提出建议。这些数据与当前的全球新冠肺炎危机和未来类似的大流行挑战直接相关。核心项目团队包括至少三名研究生研究助理、一名博士后学者和五名不同背景和不同职业阶段的教授。因此，该项目的进一步影响将是促进下一代科学家和工程师在应对大流行挑战方面的技术教育和培训。该项目包括两个阶段的方法，以解决因应对全球新冠肺炎大流行而大规模使用消毒对清洁工人造成的潜在健康威胁。第一阶段的目标是确定流经个人防护口罩的化学物质的可能浓度范围，其依据是：1)所用消毒剂的类型；2)应用过程(如擦拭、喷雾或喷雾)；3)形成副产品的化学过程(如清洁产品在表面上的反应)；4)环境条件(如通风/稀释率)；以及5)清洁工人与化学源的接近程度。第二阶段的目标是确定吸入消毒副产品的特征。配备鼻子和嘴巴呼吸模拟系统的全尺寸保暖假人将暴露在环境室内第一阶段确定的均匀浓度的副产品中。将使用不同的口罩研究表面化学反应过程和动力学，并将通过质谱仪评估副产品吸入。假人将配备四种不同类别的口罩：外科口罩、无呼气安全阀的防尘口罩、有呼气安全阀的防尘口罩和专业口罩。一些口罩可能会减少吸入消毒副产品，而另一些口罩则通过将清洁产品蒸气吸附到口罩上以及因呼出而增加湿气而增加暴露。这些过程导致面罩化学物质产生额外的化学产品，其在面罩中的浓度比环境空气中的浓度高得多。这些次级产品可能比清洁产品的初级蒸气危害更大。这项研究的成功完成将通过确定不同类型口罩和清洁产品的风险，及时提供与当前危机有关的关键数据。这些信息将为使用口罩保护清洁工人的健康提供建议。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

To curb the spread of COVID-19, communities across the world are disinfecting buildings and other public places. Cleaning workers wear different levels of personal protection ranging from simple surgical masks to professional high efficiency filtration masks. Depending on the mask type, cleaning process, surfaces, and disinfectants used, cleaning workers can be exposed to disinfection byproducts that form as a result of reactions between disinfectants, the surfaces being cleaned, and the mask materials. This project will quantify inhalation of disinfection byproducts during disinfection while wearing different classes of masks and use this information to make recommendations on which mask to wear and how often to change or clean the mask or mask components. These data are directly relevant to the current worldwide COVID-19 crisis and similar future pandemic challenges. The core project team includes at least three graduate research assistants, one postdoctoral scholar, and five professors with different backgrounds and at different stages of their careers. Thus, a further impact of this project will be advancing education and training the next generation of scientists and engineers in techniques to respond to pandemic challenges. This project consists of a two-phase approach to address potential health threats to cleaning workers resulting from the large-scale use of disinfection in response to the global COVID-19 pandemic. The goal of the first phase is to define possible concentration ranges of chemicals that flow through personal protection masks based on: 1) the type of disinfectant used; 2) the application process (e.g. wiping, spraying, or fogging); 3) chemical processes forming byproducts (such as reaction of cleaning products on surfaces); 4) environmental conditions (such as ventilation/dilution rate); and 5) proximity of the cleaning worker to the chemical source. The goal of phase two is to characterize the inhalation of disinfection byproducts. A full-scale thermal manikin equipped with a nose and mouth breathing simulation system will be exposed to uniform concentrations of byproducts determined in phase one in an environmental chamber. Surface chemical reaction processes and kinetics will be studied with different masks and byproduct inhalation will be assessed via mass spectrometry. The manikin will be equipped with four different classes of masks: surgical mask, dust mask without exhalation relief valve, dust mask with exhalation relief valve, and professional mask. It is likely that some masks decrease inhalation exposure to disinfection byproducts while others increase exposure via adsorption of cleaning product vapors to the mask and by addition of moisture due to exhalation. These processes lead to a mask chemistry that produces additional chemical products whose concentration is much greater in the mask than in the ambient air. These secondary products are potentially more harmful than the primary vapors of cleaning products. Successful completion of this study will provide timely and critical data relevant to the current crisis by identifying risks for different types of masks and cleaning products. Such information will inform recommendations on mask use to protect the health of cleaning workers.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.