Watching London's air quality performance is a bit like watching the final overs of England v Bangladesh - just because England hadn't lost yet didn't fill you with any confidence that the outcome would be anything other than defeat.
It looks like the European Commission have given London a conditional exemption (so we won't get fined yet). Boris will have to revise his Air Quality Strategy (which surely vindicates those who said it wasn't fit for purpose), and will have to include short-term measures.
This appears to mean that should limits be breached after June 2011, short-term measures will have to be invoked, which could mean banning highly-polluting vehicles from areas within London. According to the Campaign for Clean Air:
The Commission considers there may be a risk of the PM10 daily limit value being exceeded after the exemption period ending on 11 June 2011. The time extension reapplication to comply with the PM10 daily limit value in London has therefore been granted on the condition that short-term measures are introduced to control, or, where necessary, suspend activities which contribute to the risk of the limit values being exceeded. In other words: no new short-term air quality measures; no time extension.
With almost breathtaking chutzpah, the Mayor's office has reportedly said
This is a welcome recognition of the serious steps that the mayor has taken to reduce PM10 pollution in order to confront the legacy of poor air quality he inherited.
He certainly inherited poor air quality but he also inherited measures from Ken Livingstone to deal with it, including taxi emissions checks and low-emission zone changes, which he ditched, while abolishing the WEZ, which was predicted to increase traffic levels.