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These London Roads Have Breached An Annual Air Pollution Limit – And It's Only January

Less than a month into 2017, three London roads have already breached one annual air pollution limit.

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Just five days into 2017, Brixton Road in Lambeth, London, breached one of the EU’s annual air pollution limits. It was shortly followed by Putney High Street in Wandsworth, less than two weeks into the year, and last week by Brompton Road in Knightsbridge.

And on Monday afternoon, several days into an episode of particularly bad pollution levels in the capital, the mayor of London, Sadiq Khan, issued the first “very high” air pollution alert since he took over, saying that “everyone – from the most vulnerable to the physically fit – may need to take to protect themselves from the filthy air".

The European Union says the hourly average amount of nitrogen dioxide shouldn’t exceed 200 micrograms per cubic metre of air (200μg/m3) for more than 18 hours in a single year. Headlines about air pollution breaches on London roads have become a January tradition, as the capital’s streets cross that threshold before the first month of the year is even over.

“It’s like the clean-air New Year’s Day,” Alan Andrews, a lawyer with environmental law organisation ClientEarth, tells BuzzFeed News. “Ever since [EU clean-air rules] came into force in 2010, London has every year broken the hourly mean usually at some point in January.”

Brixton Road, Lambeth

Brixton Road reached its annual hourly NO2 limit on 5 January 2017 and has reached levels above 200μg/m³ 36 times this year, as of 11pm on Monday evening.

Last year it was Putney High Street that won the dubious honour of being the first road to cross the threshold, just eight days into 2016. And the year before, Oxford Street did it in just four days.

“The pollutant we have most of the problem with in London is nitrogen dioxide (NO2),” Andrew Grieve, a senior air-quality analyst at King’s College London, tells BuzzFeed News. NO2 comes from road traffic, especially diesel, and scientists know it has short- and long-term health effects.

When overall pollution levels are higher than normal, like during the current pollution episode in London, some people will feel the effects immediately. People with heart or lung conditions might notice their symptoms get worse, and people with asthma might need to use their inhaler more often than usual.

Official health advice says these people at risk should reduce strenuous activity, especially outside, during “high” pollution levels, and avoid it altogether if the levels become “very high”. The advice also says everyone else should also consider reducing activity if they develop symptoms like a cough or sore throat.


But long-term effects of exposure could be even more worrying than these short-term effects: Air pollution has been linked to asthma, type 2 diabetes, stroke and heart disease, and cancer.

A report published by the Royal College of Physicians last year said 40,000 deaths each year can be attributed to outdoor air pollution alone. While it’s hard to disentangle the specific effects of nitrogen dioxide from those of other pollutants it tends to be found with, research is beginning to show that NO2 does independently impact people’s health.

ClientEarth brought legal action against the government for the breaching of these limits in 2011. The case culminated in a High Court ruling last year that said the government’s existing plans to tackle air quality were “illegally poor” and ordered it to come up with a new plan by this April.

"They're running out of excuses, and the latest court judgment is going to make it very difficult for them to avoid taking action,” says Andrews.

Brompton Road, Knightsbridge

Brompton Road has reached NO2 levels above 200μg/m³ 34 times this year already, as of 9am on Monday morning.

London's level of pollution is even worse by other standards – the EU limits on air pollutants are based on guidelines from the World Health Organization, which has even stricter advice that states NO2 should never go above 200μg/m3 at all.

“The introduction of the 18 hours was just a political compromise based on what member states thought they could realistically achieve,” says Andrews. “The hourly 200 limit is based on evidence of the short-term impact of health effects of nitrogen dioxide. At those levels you start to see inflammation of the respiratory tract, and these sorts of symptoms.”

Grieve says: “The important thing to remember is there is no safe lower limit – there's no number that you get under and magically everyone is all right."

Putney High Street, Wandsworth

Putney High Street has reached NO2 levels above 200μg/m³ 28 times this year already, as of 11pm on Monday evening.

Amid the haze of pollution measures and rules, there does seem to be a glimmer of hope: Last week the Evening Standard reported that Oxford Street’s levels of nitrogen dioxide dropped by a third last year compared to 2015, after a switch to make more electric buses run on that route.

This drop was calculated based on provisional data collected by scientists at King’s College London, which runs the London air quality network monitoring air pollution levels across the capital. Grieve, who works in the group, says the process of confirming air pollution data typically takes months to complete. But if it does turn out that there has been a big reduction on Oxford Street, "that's great news, because it provides a template for action on other roads,” he says.

One thing the team at King’s must do to determine if the drop on Oxford Street is real is to work out how much, if any, of the effect is down to weather. “Weather has a massive effect on the data,” says Grieve. “You can't fairly compare a year where we had a long, hot summer and then a freezing winter to another year where we had a washout summer and a mild winter.”

Windy, wet weather disperses pollution, whereas hot, still days mean it builds up. Cold, clear weather, like we’ve had in the UK over the last week, is also bad news. A cold air layer builds up at ground level, with warmer air above, creating something known as a temperature inversion. Pollution is trapped in the cold layer at ground level and doesn’t disperse, building up to dangerous levels. This is what led to the infamous London smog in 1952, and also the pollution episode in London that began last week.

Focusing on problem roads, like Oxford Street, that breach air pollution limits within days of a new year might help keep those specific roads out of the headlines, but Grieve cautions against getting too hung up on them; after all, only around 100 streets in London have pollution monitoring devices installed. “Attention, understandably, is always focused on these streets that have monitoring stations on them," he says. "But there aren't monitoring stations on every single road, so it could well be that there are lots of roads in London that are even worse but don't have monitoring stations on them, so you can't know. If you think of Brixton Road and Putney High Street, they're not unique roads. They have monitoring stations on them, but they're likely emblematic of lots of roads around London.”

The government is due to share its plans to tackle air pollution by 24 April this year. “Let’s hope it’s third time lucky, because the first two plans weren’t good enough,” says Simon Birkett, founder and director of campaign group Clean Air in London.

There’s no one solution to the problem, but according to campaigners, there’s an obvious place to start.

“One of the reasons we went back to court last time was that the government was basically ignoring the problem as it related to diesel cars,” says Andrews, "even though their own evidence showed that diesel cars are a major or the biggest source of pollution in most areas in breach. Diesel transport is responsible for something like 80% of these NO2 breaches.”

Birkett agrees: "Mathematically the only way you can deal with something like this, where pollution levels are so high over such a wide part of London, is to ban diesel. It's such a large part of the source.”

Campaigners are also calling for a new network of clean-air zones across the country, investment in clean public transport, and incentives to help people trade in their diesel cars.

Andrews says we can look to other European cities for examples of how to reduce the pollution during smog episodes. Madrid, Paris, and Brussels have made public transport cheaper, or even free, during pollution episodes, and Paris even banned odd- and even-number-plated cars from the city centre on alternate days.

But we can also look to ourselves. During the Olympics in 2012, Andrews says, a public information campaign managed to reduce the number of car journeys: “If it can be done for a big sporting event like the Olympics, why can't it be done to protect public health during these smog episodes?”

Last week the mayor of London announced £1.4 million of funding to tackle air quality at a local level through various schemes, including more charging points for electric vehicles across London and a zero-emissions zone for Hammersmith town centre.

In the meantime, Birkett says, we need an effective public information campaign about how people can protect themselves during episodes of high pollution, and also how people can reduce their own personal pollution.

“You can protect yourself day-to-day a bit by going down side streets, where pollution is typically half or a third of what it is on main roads,” he says. “And when you’ve got levels as extreme as we saw [last week] on Brompton Road, where hourly levels for nitrogen dioxide hit twice the WHO guidelines for maximum human exposure, we need to be suspending some bus services, advising drivers to avoid the area, and advising pedestrians and visitors to keep away from those streets.”

Andrews says: “The mayor has got something right in that he's issued a smog warning. That's the bare minimum our politicians should be doing for us: giving us the information that we need so we can protect ourselves and our families.”


Kelly Oakes is science editor for BuzzFeed and is based in London.

Contact Kelly Oakes at

Chris Applegate is an editorial developer for BuzzFeed and is based in London.

Contact Chris Applegate at

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