How to minimise the amount of polluted air you inhale while exercising

In general, the benefits of exercise outweigh the risks from air pollution. But there are steps we can take to minimise our exposure.

I was waiting to cross the road during a recent morning run when a van pulled up beside me. I couldn't help but inhale a thick plume of exhaust smoke.

As a keen cyclist and runner living in London this can be hard to avoid. Active travel is built into my commute, so I'm often stuck behind traffic while I wait for lights to change.

As I cough away the latest wave of polluted air, I often wonder: is exercising on polluted roads doing me more harm than good?

Here's everything you need to know about the risks and benefits, as well as how to best protect yourself when exercising in urban environments. 

What's in the air you're breathing? 

It's well known that air pollution is linked to chronic health conditions including heart disease, respiratory issues, cancer as well as a higher risk of an early death. According to the World Health Organization, 99% of the global population breathes in polluted air, leading to 6.7 million premature deaths per year. 

Air pollution affects pretty much all the organs of your body, says Audrey de Nazelle, an associate professor at Imperial College London who researches the effects of pollution on exercise.

"We used to think it was just respiratory disease, but it's also [linked to] cardiovascular disease, diabetes, cognitive function and reproductive impacts," she says.

One major concern is PM 2.5, tiny particles which measure just 2.5 micrometres across. These fine specks are around 30 times smaller than the width of a human hair. They are released directly into the air from traffic, and can penetrate deep into our lungs, crossing into our bloodstream and travelling throughout the body. 

Over time, this particle accumulation can affect the brain. In a 2025 review looking at 51 studies, a team analysed data from over 29 million people and found a link between three types of air pollution and an increased risk of Parkinson's disease. One of these were PM 2.5. "When the particles are this small, they can cross the blood brain barrier, cause damage to the vessels and the barrier, but also end up in your brain," says Haneen Khreis, an epidemiologist at the University of Cambridge and a co-author of the study. 

But there are other pollutants, too. While exercising along busy roads or in cities, we will be breathing in nitrogen dioxide, which was also found by the review to increase the risk of Parkinson's Disease. Nitrogen dioxide is also thought to cause lung inflammation. In the longer term, it can impair how our lungs develop and function. Then there's sulphur dioxide, ammonia, carbon monoxide and even ground-level ozone. 

When we run, cycle or exercise vigorously, we breathe faster and more deeply. That means we tend to inhale more polluted air when running compared to walking. When covering the same distance, people exercising at a higher intensity receive a larger dose of toxic particles entering into their lungs.

But perhaps surprisingly, sitting in a car doesn't completely shield you from air pollution either. "Personal exposures when you're on a bike........

© BBC