RAPID: Effective mass spray disinfection using Unmanned Aerial Vehicles (UAVs)

Engineering - The SARS-CoV-2 persists on contaminated objects or surfaces, referred to as fomites, for long times, which may promote virus spread. Effective and efficient disinfection of surfaces in public spaces will play an important role in plans to resume business, education, commerce, and other important activities. Mass spray disinfection is currently used in multiple countries by employing Unmanned Aerial Vehicles (UAVs). While this strategy has potential benefits, such as the minimization of health risk to personnel performing the disinfection and the potential for large-scale and quick deployments, the effectiveness of mass spray disinfection, especially for Covid-19, has not been systematically examined. The goal of this RAPID project is to identify effective mass spray disinfection strategies for Covid-19, and employ UAVs to implement those strategies. The results of this project will provide effective means to mitigate the spread of Covid-19, as well as other infectious diseases (e.g., influenza), by intercepting virus transmission via fomites. The approach has the potential to be adopted as a general and scalable strategy for sanitization in hospitals, schools, and other public facilities that are susceptible to virus exposure and contact with a large number of people. To ensure the broader impact and accessibility of the research, all results will be available in open-source archives, as well as on social media dedicated to this project (e.g., Facebook, Twitter). The unique collaboration among the researchers provides an excellent opportunity for training and workforce development at the interface of multiphase flow physics, UAV engineering, and infectious diseases.

Fomites are objects or surfaces that can become contaminated with a pathogen. Studies have cited fomites as significant vectors for virus transmission in a range of environments including hospitals, schools, and offices. SARS-CoV-2 has been shown to contaminate a wide range of porous and nonporous fomites, and can persist on many surfaces for extended periods of time from a few hours to days. The long persistence time indicates the need for effective surface disinfections to intercept virus transmission and the spread of the disease. Mass spray disinfection from Unmanned Aerial Vehicles (UAVs) has many advantages including the high-tempo coverage of large and difficult-to-reach areas, and the minimization of health risks to personnel performing the disinfection. Nevertheless, the basic science that underlies the effectiveness of such mass spray strategies has not been examined. Instead, most prior work on surface disinfection is highly empirical. This project will develop a physicochemical understanding behind the empirical results. The project aims to address these gaps, and will determine the spray parameters and the underlying physics for effective disinfection under different conditions, and devise perception and decision-making algorithms that allow a UAV equipped with programmable sprayers to implement the spray strategies identified.

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.