After steady rises in air quality up until the turn of the century, London should be well on the way to tackling one of the most serious public health concerns today.
Instead the city has some of the most polluted air in Europe.
Average concentrations of dangerous air pollutants in 2008 were more than three times greater than safe limits established by the World Health Organisation (WHO), and the capital's deteriorating air quality is estimated to directly contribute to around 6-7,000 deaths every year.
The Greater London Authority estimates some 700,000 Londoners live in areas expected to breach legal standards for Nitrogen Oxides, which can cause lung problems, in 2010.
Nationally, twice as many people today suffer from lung disease and asthmatic conditions caused by air pollution than did 20 years ago.
Pollution targets ignored
Under EU laws introduced five years ago, London, along with other cities in the UK and Europe, should have taken action to reduce levels of dangerous airborne particles.
But it has failed to meet every single one of the reduction targets since they came into force in 2005. When the EU issued warnings, the UK Government simply ignored them.
Now, after being threatened with a £300 million fine, it is seeking permission to delay meeting the targets and improving air quality in London.
While the fines are imposed on the UK government, responsibility for tackling air pollution actually lies with the London Assembly and Mayor Boris Johnson.
His response to the health crisis has been, to the dismay of campaigners, another delay.
In February 2008, former Mayor Kevin Livingstone introduced the Lower Emission Zone (LEZ) which requires owners of large lorries, buses and coaches to meet emission standards.
The LEZ aimed to reduce pollution from diesel exhaust, which is a major source of nitrogen oxides (NOx) and particulate matter (PM).
PM, which refers to any airborne particles small enough to pass into the lungs, is seen as particularly dangerous. Although by definition it can consist of all kinds of material carried by the wind, its main source is road traffic and diesel vehicles.
Livingston's LEZ was due to be extended to some of the major diesel emitters - vans and minibuses - in October 2010, but the new mayor postponed the plans until 2012 because of fears about its impact on small businesses during the recession.
This two-year delay has left London, in the words of Green Party London Assembly member Darren Johnson, 'without a hope in hell of reaching EU legal standards - let alone WHO limits - any time soon.'
Johnson chaired an Assembly investigation into air pollution earlier this year. As well as calling for the extension of the LEZ, the report, published in May 2009, also recommended tough additional action in hotspot areas around London.
'You only need to look at the pollution maps to see the appalling levels - it's perfectly reasonable to take some faster measures in the hotspots,' said Johnson.
Such immediate action seems unlikely. The Mayor's own Air Strategy proposals, which include planting trees, cleaner buses and local traffic measures are not expected to come into force before 2012.
'The timetable is far too relaxed for something that is leading to the premature death of thousands of people every year,' says Johnson.
In the most recent survey of attitudes in 2008, one-third of residents in Westminister cited 'poor air quality' as their biggest environmental concern.
In evidence to the London Assembly's investigation, a teacher from Stoke Newington, in North London, said:
‘Many people in this area suffer heavy colds, congestion,sinusitis and respiratory problems. Our houses are constantly filled with a really fine powder despite our efforts to keep them clean. What is going into our lungs?’
The UK Government and the Mayor of London are hopeful that their Air Strategy proposals will help avert EU fines for failing to reduce air pollutants. But campaigners say it fails to give Londoners a timetable for when air quality will meet EU safe limits.
The environmental law group ClientEarth has written to the EU urging them to refuse the extension, and to press ahead with a fine.
'It has been ignored for over a decade and now they're trying to tackle it at the last minute and no credible plan has been put forward,' said ClientEarth lawyer Alan Andrews.
'It's London’s dirty little secret,' he said.
Tough policies needed
The Campaign for Clean Air in London (CCAL) says even the Mayor's delayed and in many cases unfunded proposals will not be enough to reduce air pollution below EU safe limits.
'He says road transport produced 83 per cent of PM emissions in central London in 2006,' said Simon Birkett, from CCAL.
'The Air Quality Strategy suggests this huge problem can be dismissed as just 'a few hotspots' and tackled by planting street vegetation, unspecified and unfunded local traffic measures and cleaner buses on these most polluted roads.
'The bottom line for the Mayor and the Government is that this strategy needs to tackle a problem estimated to have resulted in 6,300 to 7,900 premature deaths in London in 2005 due to dangerous airborne particles alone – and it does not,' he said.
Green Party member Johnson says the Government has 'underplayed' the problem in the past.
'There has been a tendency in the past to see this as an abstract environmental issue rather than a devastating health issue.
'This can't be a buck-passing exercise between national Government and London - they need to work together to ensure the necessary plans and funding are in place.'
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