Protecting Transportation Employees and the Traveling Public from Airborne Diseases (2024)
Chapter: 1 Introduction, Research Objectives, and Overview of the Work Plan
Chapter 1
Introduction and Research Objectives
It is of public and transit’s interest and importance to develop and adopt advanced cabin air control systems and measures, which can lower the risk of transmission of airborne disease substantially, for more sustainable and resilient public transportation. This project conducted a series of experiments and investigation to understand: (1) effective short- and long-term contagion mitigation strategies and practices, (2) better methods for conveying information, and (3) more thorough implementation guidance (that addresses costs and effectiveness). This will assist transportation agencies’ responses to the COVID-19 pandemic and prepare for future pandemics.
Overview of the Work Plan
The work plan was composed of two primary technical components – studies conducted with buses and a literature synthesis. The bus studies consisted of an experimental component that addresses the impact of 1) clear barriers, 2) cabin air filtration, 3) on-board High Efficiency Particulate Air (HEPA) filtration, 4) ventilation conditions, and 5) parallel ventilation systems on the transmission of COVID-19-sized aerosols in a city bus. Two full-scale buses were used in stationary and on-road tests. These studies were supplemented with computational fluid mechanics models (CFD) and some results were validated in on-road experiments.
In parallel with this, the literature synthesis was conducted on the following topics that are COVID-19 mitigation strategies: 1) effect of dilution by ventilation, 2) effect of PPE/masks, 3) effect of surface cleaning, 4) effect of cabin air filtration, and 5) effects of Plexiglas barriers. This literature synthesis was conducted in the context of public transportation safety and risk reduction. Additionally, the literature synthesis was conducted on exposure and infection rates in buses, trains, and airplanes. This was followed by a significant review of aircraft ventilation strategies, which are known to provide a highly protected cabin environment. These results were combined to generate effective mitigation strategy recommendations for practitioners, methods to improve current practices, and suggestions for implementation.
