London has been put on “very high” alert as cold and still weather, traffic, and a peak in the use of wood-burning stoves combined to send air pollution soaring in the capital and across swaths of the UK.
According to data from King’s College London, areas of London including Camden, the City of London and Westminster all reached 10 out of 10 on the air pollution index, with many other areas rated seven or higher.
The forecast for Tuesday is that air pollution levels will remain unacceptably high in the capital with pollution levels expected to similarly persist in other areas across the country.
“Today the shameful state of London’s toxic air has meant that I am forced to trigger the first ‘very high’ air pollution alert under my new comprehensive alert system,” said the Mayor of London, Sadiq Khan.
“This is the highest level of alert and everyone – from the most vulnerable to the physically fit – may need to take precautions to protect themselves from the filthy air.”
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Researchers said the pollution is primarily down to particulates, although nitrogen dioxide is expected to reach moderate levels at roadsides in rush hour.
“This is a particularly bad pollution episode,” said Timothy Baker of the environmental research group at King’s College London. “The peak we saw [on Sunday] night was the highest level [of PM2.5 particulates] since April 2011 as an average across London.”
According to the latest data from the Department for Environment, Food and Rural Affairs, by Monday evening eight regions of the UK were rated as having high or very high levels of air pollution, including the south-east, south-west, the east Midlands and Northern Ireland.
In particular, parts of Bristol, Belfast and Nottingham were among those flagged as having high 24-hour mean levels of PM2.5 particulates.
Baker and colleagues said that London’s plummeting air quality was down to the onset of chilly weather and a lack of wind that had enabled the accumulation of local pollutants, with high levels of particulates from traffic and wood burning adding to the problem.
“This episode is actually a perfect illustration of all the things that control air pollution,” said Baker. “The weather conditions happened to coincide with the two peaks – one from the traffic, one from the wood burning – and then that was on top of what we had already built up locally over a number of days and a bit coming in from the continent.”
A similar set of ingredients, he added, was likely to be behind the increase in air pollution in other regions of the UK and Europe.
The continued cold snap, added Baker, meant that the city’s problem was unlikely to clear until later in the week, with particulate levels for Tuesday predicted to remain high to very high.
“The wood-burning contribution we’ll expect to fall a little, but the traffic contribution we are expecting to increase,” he said.
And while the wind was expected to pick up later in the week, dispersing local emissions, there was a chance that imports of air pollution from the continent could increase.
In response to the high levels of air pollution, people were being advised to reduce physical exertion, with Sir John Cass’s primary school in Aldgate, London, reducing outdoor activity for under fives.
Pedestrians, said Baker, could also reduce their risks by using side roads to reach their destinations. “Even though pollution is elevated everywhere across London at the moment, you can still limit your exposure somewhat by just not walking along main roads,” he said.
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Earlier this month it was revealed that parts of London had surpassed their entire annual air pollution limit in the first five days of the year.
The public health impacts of air pollution, meanwhile, continue to unfold, with dementia, heart attacks and strokes all linked to poor air quality.
Simon Birkett, the founder and director of the campaign group Clean Air in London, raised concerns that messages around the dangers of air pollution were failing to be delivered to those outside the capital.
“Three hundred people died early during one winter air-pollution episode in 2014. For goodness sake, therefore, why has this government stopped distributing press releases to warn people about the highest levels of air pollution? At least Londoners have Sadiq Khan warning them,” he said.
Baker agreed that the time for action was now. “[This] is yet another piece of news which highlights the importance of trying to do something about air pollution across the board,” he said.
“This is the sort of thing that leads to the sort of figures that are given as to the number of early deaths that occur because of air pollution – because it is something that impacts on the whole population.”