Infection risk in cable cars and other enclosed spaces

Area of Science:

• Epidemiology
• Environmental Health
• Aerosol Science

Background:

• Indoor environments facilitate airborne infection spread, as demonstrated during the COVID-19 pandemic.
• Concerns have been raised regarding the potential role of cable cars in disease transmission.

Purpose of the Study:

• To experimentally assess cable car ventilation.
• To develop a general stochastic model for airborne infection risk in enclosed spaces.
• To compare infection probabilities in cable cars versus other indoor settings.

Main Methods:

• Experimental characterization of natural ventilation in cable cars.
• Development of a stochastic infection model incorporating epidemiological, virological, and indoor parameters.
• Calculation of infection probabilities based on air exchange rates and occupant density.

Main Results:

• Cable cars exhibit high air exchange rates (up to 180 ACH).
• Infection probability in cable cars with open windows is significantly lower than in aircraft, trains, offices, and classrooms.
• Infection risk in cable cars is 2-3 orders of magnitude lower than in other considered indoor spaces.

Conclusions:

• Cable cars, particularly with open windows, present a low risk for airborne infection transmission.
• The developed model provides a framework for assessing infection risk in diverse indoor environments.
• Inhaled viral dose serves as a practical upper bound for infection probability, facilitating comparisons across settings.