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Twelve misconceptions about air pollution

Simon Birkett18/06/2014 - 13:00

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London's busiest roads are over legal limits
London's busiest roads are over legal limits

Air pollution in our biggest cities is much worse than most of us have realised. It averages well over twice World Health Organisation (WHO) guidelines and legal limits near many of London’s busiest roads. In the first of an occasional series, Simon Birkett, the director of Clean Air in London, details the 12 most common misconceptions about air pollution.

Cartoons by Andy Davey @DaveyCartoons.




1. Air quality is better than it was


Visible coal smoke disappeared after the Clean Air Act and has been replaced by diesel exhaust and other largely invisible particles and gases. During this time, the certainty and scale of the health effects of air pollution have rocketed upwards while public understanding has remained where it was 30 years ago for smoking.


2. Particles are more dangerous than gases


We’re worried about particles and gases. Around 15 years ago scientific studies began showing the health impacts of long-term exposure to dangerous airborne particles (PM2.5 and PM10) were much greater than impacts due to short-term exposure. Nowadays NO2 is the only regulated gas and recent studies suggest the health effects of it on mortality may be as great as those of PM2.5 and largely independent of them.


3. Air pollution is much worse in Beijing than London

Levels of dangerous airborne particles are higher in Beijing (and Eastern Europe) than London, though not always. A leading UK scientist said recently that Oxford Street may have the highest officially monitored levels of nitrogen dioxide (NO2) in the world at well over three times the World Health Organisation (WHO) guideline and legal limit.


4. People die from breathing difficulties

The Committee on the Medical Effects of Air Pollution estimated around 80 per cent of deaths attributable to air pollution can be classified as cardiovascular with those affected losing about two additional years of life at typical ages for heart attacks and strokes. The latest report from the WHO estimated outcomes caused by outdoor air pollution are mainly heart disease (40 per cent), stroke (40 per cent), chronic obstructive pulmonary disease (11 per cent) or lung cancer (6 per cent). They called it the largest single environmental health risk. Only smoking causes more early deaths.


5. It’s not like we’re breaking the law, or anything


Air pollution near our busiest streets is well over twice the legal limit. The UK said it complied with PM10 legal limits in 2012 but NO2 limits were breached in 34 of 43 UK zones in the same year. The London mayor estimated 1.7 million people in London were exposed to NO2 above the legal limit in 2012. The European Commission singled out the UK for infraction action on NO2 in February 2014.


6. Tube dust is ‘safe’


Scientists still believe that particle mass concentrations are the best way to predict the main health effects from air pollution. Such tube dust concentrations may exceed 1,000 μg/m3 at the worst places in the London Underground i.e. around 20 times the WHO guideline for average daily exposure.


7. Diesel is better for the environment than petrol


Diesel vehicles may emit slightly less carbon dioxide than petrol vehicles but 10 to 20 times the PM2.5 and NO2. The WHO classified diesel exhaust carcinogenic to humans in 2012.


8. Wood burning is good for the environment and green walls are the answer


It is illegal to burn wood in open fires in Smoke Control Areas which were established after the Clean Air Act in many parts of London and other cities. Lots of people are ignoring the law and causing about 5 per cent of PM10 over London. Everyone loves greenery but ‘offsetting’ is never the answer or sustainable as air pollution must be tackled at source.


9. They protect you in hospitals, don’t they


The Department of Health is still refusing to ensure healthcare buildings comply with British and European indoor air quality standard EN13779. Remember buildings can have any, all or none of (mechanical) ventilation, air conditioning and filtration.


10. There’s nothing I can do about it


Find out about air pollution near where you live, work and play. You can protect yourself by walking or cycling down quieter streets and reduce pollution for yourself and others by walking, cycling or using public transport rather than driving a diesel vehicle. Check health advice during air pollution episodes, which occur about 12 times a year in London, and get the CityAir, Clean Air in Cities and London Air apps. Become a campaigner.


11. Why don’t I know about this?


Successive governments and others have covered up the problem. For example, the Mayor of London sprayed pollution suppressant by monitors most-used to warn of smog episodes and report legal breaches and the current government has breached the requirement to warn of smog on a number of occasions.


12. What’s the good news?


As we come up to 60th anniversary of the first Clean Air Act for the City of London Corporation on 5 July, there is a wonderful opportunity for London to mobilise political will, technology and behavioural change to show the world again how to tackle wider air pollution, climate and sustainability issues.


Simon Birkett can be followed at @CleanAirLondon

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