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Air Quality

Across London, levels of harmful pollutants regularly exceed UK and EU Air Quality Standards and objectives, posing a serious threat to human health[1].

Despite measures to reduce emissions, high levels of nitrogen dioxide (NO2) and particulate matter (PM10) remain, putting the capital’s millions of residents, workers and visitors at increased risk of respiratory and cardiovascular damage[2].

But a little bit of awareness and planning can mean that everyone can play a role in helping clean up London's air and also move around the city in a healthier, safer way. 

Air Quality & Breathing Space

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Breathing Space visualises the live NO2 levels at 11 locations across London. The readings are fed to LED lights which change in colour depending on the level of pollution in that particular area. The colour banding is based on the DEFRA Daily Air Quality Index. 

Click to enlarge.

Click to enlarge.

Why Should We Care About Air Quality?

Thousands of Londoners die early every year  as a result of poor air quality [3], and pollutants can have a significant effect on your health. To see how each pollutant affects your body, click on the infographic.

Air Quality in Space & Time

Many air pollutants come from road transport, so it is unsurprising that on average, the air quality near these roads can be very poor [4]. The impact of busy roads on air quality is made very clear on the annual average NO2 map of London produced for 2013 by the GLA [5]. Air quality also changes throughout the day, due to volumes of traffic & weather conditions. Particularly warm, sunny days will generate more ground level ozone [6], whereas cooler, breezier days will typically record lower levels of pollutant. Choosing a route which avoids main roads, particularly in rush hour, can significantly reduce your exposure to harmful pollutants. 


We also did a short experiment* around Breathing Space, taking NO2 measurements to see just how localised air quality can be. Watch the video to see our results.

What Can You Do To Reduce Your Exposure?

There are a number of choices you can make every day to reduce your exposure to poor air quality.  

  • As the majority of pollutants are generated by vehicles, choosing to walk or cycle away from major transport routes or travel outside rush hours will help to avoid the highest concentrations [7].
  • Breathing faster whilst doing sport means that you are breathing in a higher quantity of these pollutants [8], so the considerations regarding where and when to exercise are even more important. 
  • Keep an eye out for peaks in pollution, and reduce your activity during these times, as recommended by the government [9].
  • Your chosen mode of transport may also play a part in reducing the amount of harmful pollutants you breathe. The concentrations inside vehicles can be much higher than outside them, studies suggest [10]
  • Through the Mayor’s Air Quality Fund, the Mayor of London has supported the Cleaner Air Better Business (CABB) project to develop an interactive map of London that allows you to put in any route and be shown a low pollution walking option. To visit the site and plan your next journey click here

[1] London Air: ‘During pollution episodes, roads in London can exceed the annual limit in a single day’

[2] ‘Particulate pollution can harm our heart and lungs – it is linked to asthma and death’; ‘NO2 can inflame the airways and long-term exposure can affect lung function and breathing – it can also worsen asthma’

[3] Transport for London: 'Every year, around 9,400 deaths in London are attributed to illnesses related to air quality'

[4] London Air: 'In London, pollution concentrations with a few metres of busy roads are normally 2 or 3 times those at background locations'

[5] London Atmospheric Emissions Inventory (LAEI) 2013

[6] London Air: 'on sunny days in polluted air concentrations of ozone can increase ' 

[7] London Air: '...walking along back roads rather than beside busy roads will reduce your exposure to traffic pollution'

[8] London Air: 'The faster you breathe the more airborne pollutants are delivered to your lungs. By changing your exercise routine you can reduce your exposure' 

[9] DEFRA: When air pollution is very high -  'Reduce physical exertion, particularly outdoors, especially if you experience symptoms such as cough or sore throat.'

[10] BBC: 'It's better for the environment if you leave your car at home and better for your health. It exposes you to less air pollution, you're not contributing to the problem, and you are getting the benefits of exercise.'


*Data collected using ScienceScope Graphic Logger Enhanced with NO2, VOC, CO & CO2 attachments. Pollutant visualised on maps is NO2. Data collected by walking a repeated route at different times over several days, starting at the time indicated in the video and ending ~1hour later.