• Guides & Advice

By: Nick Geary

Updated: 20th September 2023

Parkrun is now a well established international concept; statistics show over three million runners take part worldwide, with over one-third of the UK's parkrun locations surrounding the M25 corridor. But, with reports of dangerously high nitrogen dioxide in this area, are these routes damaging runner's health?

Here at Boiler Guide, we've done the number-crunching using data released by Imperial College London and the University of Leicester. Using their assessment of NO2 levels for green spaces dotted around the M25 corridor, we analysed official parkrun routes to assess the air pollution levels at each location.

Following standards set by the EU and World Health organisation for 'safe' limits of ?g/m3 per year, we compared N02 levels for parkrun locations in London. This helped us build a picture of which parkruns in London are the best for respiratory health and which are the worst.

As you can see, the leading park runs with the cleanest air in London are Orpington (25.6?g/m3), Harrow Lodge (27.2?g/m3) and Raphael (27.3?g/m3). With levels of N02 between 22-30?g/m3, these parkrun locations are well within the EU safe limit for clean air.

At the other end of the scale, the air has reached dangerous levels at Burgess Park (40.8?g/m3), Mile End (40.4?g/m3) and Hackney Marshes (40.2?g/m3). These NO2 readings are beyond the safe limit of 40?g/m3, where runners are missing the benefits of running in cleaner air, instead being exposed to high levels of air pollution.

The top 10 parkruns inside the M25 with the highest levels of NO2, according to the study are:

Whilst, the top 10 with the cleanest air are below:

Our Founder, David, had this to say about the results:

"Parkrun is a brilliant initiative and we don't want these results to put anyone off getting down to their nearest 5k route on a Saturday. Volunteers dedicate their own time every week to give people the opportunity to exercise in a safe space with other people, and build a sense of community.

"We wanted to put this study together to not only inform runners who are trying to keep healthy and have fun, about the impacts of running in areas of high air pollution, but to provide a further call to local councils and the public that work must be done to address the balance. There is no longer an excuse for those not to employ renewables or other new forms of tech designed to reduce a person's carbon footprint.

"We know that prolonged exposure to high levels of NO2 can cause damage to our lungs and has been linked to childhood asthma, reduced lung growth and reduced brain function and it's integral that government officials and the wider public stand up and do what they can to make our greener spaces even more greener."

That's not to say efforts are not already being made; the London 'Ultra Low Emission Zone' launched in April, both traffic and the number of polluting cars has decreased in the area. In fact, now, 13,500 fewer polluting cars drive in the ultra-low emission zone daily. This initiative followed the success of the 2017 'toxicity charge' in London which triggered a 36% decline in nitrogen dioxide in the central zone.

Despite this step in the right direction, it seems the battle with air pollution in Greater London is far from over. With evidence to suggest that high levels of NO2 can negatively impact running performance and the overall benefit of exercise outdoors, we want to ensure those running their weekly 5k in and around the capital have access to the clean air they deserve.

About the author

Nick Geary

Nick has a wide range of experience writing about conventional and renewable heating solutions, and is always increasing his knowledge by researching any new heating technologies on the horizon.