Airflows inside passenger cars and implications for airborne disease transmission

TL;DR

This study uses numerical simulations to analyze airflow patterns in passenger cars and suggests that strategic ventilation can reduce airborne disease transmission risk.

Contribution

It introduces a detailed simulation approach to evaluate how different ventilation configurations affect pathogen spread inside car cabins.

Findings

Airflow patterns significantly influence pathogen dispersion.

Cross-cabin airflow can reduce transmission risk.

Ventilation strategies impact residence time of airborne particles.

Abstract

Transmission of highly infectious respiratory diseases, including SARS-CoV-2 are facilitated by the transport of tiny droplets and aerosols (harboring viruses, bacteria, etc.) that are breathed out by individuals and can remain suspended in air for extended periods of time in confined environments. A passenger car cabin represents one such situation in which there exists an elevated risk of pathogen transmission. Here we present results from numerical simulations of the potential routes of airborne transmission within a model car geometry, for a variety of ventilation configurations representing different combinations of open and closed windows. We estimate relative concentrations and residence times of a non-interacting, passive scalar -- a proxy for infectious pathogenic particles -- that are advected and diffused by the turbulent airflows inside the cabin. Our findings reveal that creating an airflow pattern that travels across the cabin, entering and existing farthest from the occupants can potentially reduce the transmission.