We are lucky to live in a beautiful part of London with lots of green space.

However, when it comes to air pollution, Hampstead is not the green oasis we would like it to be. Our narrow streets are often clogged with traffic, especially during school run and commuting hours.

In 2015, Hampstead Neighbourhood Forum carried out an air pollution study which found that nitrogen dioxide (NO2) pollution exceeded UK legal limits in many Hampstead locations. This is worrying because air pollution contributes to many serious health problems - asthma, stroke, cancer and even dementia - with children and the elderly being particularly vulnerable.

In October 2021, the Forum decided to conduct a year-long project, measuring air pollution in 10 Hampstead locations.

Ham & High: Katharina Schauer has looked at the results of Hampstead's air pollution testsKatharina Schauer has looked at the results of Hampstead's air pollution tests (Image: Katharina Schauer)

We are very grateful to our generous donors and wonderful group of volunteers including the pupils and teachers from three local schools, Devonshire House, UCS Junior School and Maria Montessori, who changed all 30 diffusion tubes every month. Under the guidance of Camden Council, we were able to produce reference quality data.

We discovered that NO2 air pollution decreased in most locations, with average levels 19% lower in November 2021 than November 2015.

This suggests that the Ultra Low Emission Zone extension (ULEZ), improvements in engine technology and an increase in electric cars have had a positive impact.

However, annual average pollution levels were still above or close to the UK legal limit in South End Green, Pond Street, Heath Street and Rosslyn Hill. Levels were above the World Health Organisation annual limit in all 10 locations, including at Viaduct Bridge on Hampstead Heath.

Detailed project results are available on the Forum’s website: hampsteadforum.org

Pollution levels fluctuated throughout the year and peaked in winter, but remained above the WHO limit throughout the 12 months.

We can only assume that during peak periods pollution levels are much higher than the monthly averages we observed.

Our study did not cover other pollutants, including dangerous particulate matter, which is produced by motor traffic and wood-burning stoves. Wood burners have become very popular and are the largest source of PM2.5 air pollution in the UK. Even eco-stoves produce about 300 times as much particulate matter as a gas boiler.

While it is encouraging that our measurements have shown that local air pollution has decreased since 2015, there is still a lot that needs to be done to make Hampstead’s air safe for everyone.

Katharina Schauer is co-leader of the Hampstead Neighbourhood Forum’s air quality project.