London targets WHO air quality limits by 2030

London will aim to go beyond EU air quality targets and meet the World Health Organization’s health-based guidelines for restricting particulate matter by 2030, the Mayor’s draft Environment Strategy has stated.

Launched for consultation today, the strategy contains a range of measures including a pledge for a £9 million Greener City Fund, which will be available for projects to boost trees and green infrastructure, as well as measures to tackle waste within the capital.

London will seek to meet WHO particulate matter limits by 2030, the Mayor’s draft Environment Strategy has stated

The Mayor also pledged that London’s air quality will be among the cleanest of any world city by the middle of the century.

Writing in his introduction to the report, the Mayor of London, Sadiq Khan, recognised air pollution as among the most significant environmental challenges faced within the city.

He wrote: “More than 9,000 Londoners die prematurely every year as a direct consequence of our air, which is so dirty it repeatedly breaches legal limits. Air pollution has been linked to asthma, strokes, heart disease and dementia — and is also to blame for children in parts of our city growing up with underdeveloped lungs. Indeed, some of the worst pollution hotspots are around schools.”


As well as outlining existing measures such as the T-charge, due to come into effect in October, the Mayor has pledged that London’s air quality ambitions — particularly for particulate matter — will go beyond current legal requirements.

In doing so, the strategy commits to meeting the World Health Organization’s ambient air quality guideline limits for the emission of particulate matter, which are based upon studies into the health impacts of exposure to elements such as sulphate, nitrates, ammonia and sodium chloride.

The guideline values state that there is a risk of potential harm to health if PM2.5 levels exceed an annual mean of 10 μg/m3. For PM10 WHO recommends a maximum annual mean limit of 20 μg/m3.

This would go beyond current levels set out in law under the EU’s Air Quality Directive, which sets a mandatory 25 μg/m3 PM2.5 target, alongside a 40 μg/m3 objective for PM10.


Sources of PM2.5 and PM10 include tyre and break wear from road transport as well as emissions from wood burning.

Outlining a number of measures already in motion, the strategy notes: “This strategy also recognises the need to go beyond legal limits, as these reflect political and economic considerations as well as health impacts. These should therefore be treated as a starting rather than an end point.

“WHO guidelines, meanwhile, were driven solely by the available health evidence and as a result are set much tighter for PM10 and PM2.5. Achieving these more ambitious targets would provide many extra health benefits for Londoners. This strategy sets out the timescale, and the changes needed, to achieve these tighter targets.”

It adds: “Progress in dealing with PM emissions will stall in 2020 once exhaust emissions are significantly reduced. London is currently far from achieving WHO health-based limits for PM2.5. One of the best ways to do this would be to reduce the number of vehicle kilometres by supporting a mode shift to walking, cycling and public transport. It will also be necessary to address wood burning related emissions, which evidence suggests are a significant source of emissions, particularly on some of the most polluted days.”


Policies set out within the Environment Strategy follow on from the Mayor’s draft Transport Strategy, published for consultation in June, which set out an ambition for London’s transport system to become ‘zero emission’ by 2050 (see story).

The Mayor’s draft Environment strategy consultation runs until 17 November.


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