What are the chances of catching Covid-19 in a cab? New study paints a grimmer picture

According to the research, the driver was at slightly higher risk than the passenger since the average airflow in the car goes from back to front, but added that both occupants experience a dramatically lower transfer of particles.

As per the study, opening windows increases the number of air changes per hour (ACH) inside the car that reduces the overall concentration of the virus. The study showed that different combinations of open windows created different air currents inside the car that could either increase or decrease exposure to remaining aerosols. Since the occupants in the simulations were sitting on opposite sides of the cabin, researchers said very few particles ended up being transferred between the two.

The study yielded counterintuitive results when all windows were down. Citing an example of one such instance, scientists said opening the windows next to each occupant carried a higher exposure risk, compared to putting down the window opposite each occupant. "When the windows opposite the occupants are open, you get a flow that enters the car behind the driver, sweeps across the cabin behind the passenger and then goes out the passenger-side front window," said Kenny Breuer, a professor of engineering at Brown University and a senior author of the research. "That pattern helps to reduce cross-contamination between the driver and passenger," Breuer said.

The scientists said airflow adjustments are no substitute for mask-wearing by both occupants when inside a car, adding that the findings are limited to potential exposure to lingering aerosols that may contain pathogens. Citing another limitation of the study, the scientists said it did not model larger respiratory droplets or the risk of actually becoming infected by the virus.