Air quality is probably the last thing we think about when debating whether to walk or drive to work. But based on research conducted by researchers at the University of Leicester, that’s a mistake. It seems there is a significant difference in air quality for those who commute by car. Drivers, as it turns out, may be exposed to higher levels of toxic gases in the air they breathe.

Experts, using air quality sensors, determined that the levels of nitrogen dioxide (NO2)—a marker of air quality that can be harmful to humans when inhaled—were higher for those commuting to work on a regular weekday morning than for those traveling the same routes on foot or by bicycle. At the same time, the walkers and cyclists were exposed to slightly higher levels of fine particulate matter (PM2.5). Researchers obtained these results by testing air quality along four popular routes that take commuters from the suburbs to the city center. The walkers and cyclists were outfitted with air quality sensors in their backpacks. A similar device, meanwhile, was placed in the cabin of a Nissan Leaf electric vehicle. An electric car was chosen to eliminate exposure to pollutants from car exhaust.

Even in an electric car cabin, however, NO2 concentrations were higher than for those just walking or cycling along the road. The researchers did remark, however, that NO2 can be drawn directly into the cabin by way of exhaust from the cars ahead. As we make the switch from gas-powered to electric cars, this will no longer be the case. Meanwhile, however, you’re better off out of the car and on a bike or your own two feet.

Air Quality and Mistaken Assumptions

Dr Rikesh Panchal, a research associate within the University of Leicester’s Centre for Environmental Health and Sustainability, and lead author for the study, said:

“Anecdotal evidence on public perceptions of air quality during commuting collected by Leicester City Council suggested that people believed that exposure to harmful pollutants was higher for active commuters than for car occupants.

“However, the results of this study show that commuting by car in cities during rush hour can result in larger concentrations of pollutants for people inside the vehicle compared to walkers or cyclists making the same journey. This heightened exposure can have detrimental effects on health.

“Additionally, there are well known health benefits of exercise through walking or cycling. Therefore, policies and incentives that encourage drivers to get out of their car and take up active commuting will benefit many aspects of commuters’ health as well as improving the overall air quality of the environment.”

It All Began with a Question

The study, conducted in conjunction with Leicester City Council’s transport and public health teams, was inspired by a question that was asked of Hannah May, who runs the city council’s business engagement program:

“It came out of conversations at our active travel roadshows, which we hold at workplaces to help businesses support their staff with sustainable travel,” said May. “We were asked how air quality might affect people who travel on foot or by bike in Leicester. I wanted to know what the scientific evidence was.

“Thanks to our partnership with the University of Leicester, I was able to take this idea to them. We carried out 16 weeks of testing and the university came up with the methodology and protocol, and did the data analysis. Together, we’ve come up with a fascinating piece of research that will help people to make informed choices about the way they choose to travel. We were also able to use the city council’s public health expertise to help analyze the benefits of active travel and measure them against the effects of air pollution.”

The upshot? If you can walk or cycle to work, you should. Your health will be the better for the cleaner air you’ll breathe while getting yourself to work.