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

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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.