'Hotspots' in Merton exceed EU guidelines for clean air

Updated: Sep 27, 2018


Photo: London Sustainability Exchange

For the past two years Sustainable Merton has been working with partners at the London Sustainability Exchange and the Mayor’s office in London.

We have been measuring the air quality of many sites across the borough and the results have been disturbing, with many areas exceeding the European guidelines for clean air.

The two main pollutants we need to know about are the particulates of black carbon (soot) and nitrogen dioxide (NO2).


Both are produced in Merton by road vehicles such as cars, buses and lorries and for this reason the highest levels of pollution occur on all of our busy main roads.

The poor air on these roads does not disperse very easily but lingers, trapped by the tall buildings which run down the sides of these roads.


This trapping of poor air is called the ‘canyon effect’ and results in high levels of pollution on main roads but much less on adjacent roads.


It is important to know this when planning your cycle routes, walking routes and most importantly, the route to school. This is because young children are particularly vulnerable to the harmful effects of poor air quality.


Doctors at the Whitechapel Hospital in London have discovered a causal link between poor air quality and the poor development of organs such as the lungs in babies, young children and even the unborn child. For this reason, it is vital that parents understand the need to avoid exposing their children to poor air quality whenever possible.


What can we all do to mitigate the worst effects of poor air and what can we do to improve the air in Merton?


  • When walking or cycling, use quiet side roads rather than the busy main roads wherever possible.

  • Avoid driving whenever possible.

  • If driving is unavoidable, make sure the car is serviced regularly and the tyres are at the correct pressure.

  • Avoid idling your vehicle; people who pull over to answer their phones often fail to turn their engines off.

  • Look after the young street trees in your road especially during the dry months of the year by watering when necessary.


Tom Walsh

CEO, Sustainable Merton


To receive updates on pollution levels affecting your journeys through London, download the City Air app, produced by Kings College London and the City of London Corporation.

Sustainable Merton

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