Invisible pollution kills up to 9,000 people a year in the capital. But under government plans, from school gates to shopping streets, Londoners will be breathing dangerous air until 2025. What more can be done?

“In the morning, this traffic island is packed with children and pushchairs and they are about a metre from all the exhausts,” says Shazia Ali-Webber. She is walking her three boys to school in Hackney, the eldest of whom, Zain, is eight and asthmatic.

Crossing choked Mare Street, where the heavy traffic grinds slowly past, is her biggest concern. “Children’s lung development is affected by air pollution: they have smaller lungs for life,” she says. “The government’s new plan says pollution will not fall to legal levels till 2025. But I don’t have time to wait: Zain will be 18 by then. They are condemning a generation of children to ill-health.”

Ali-Webber, like a growing number of people, is alarmed by the illegally high levels of air pollution across London and other UK cities, largely caused by diesel vehicles that meet emissions limits in official lab tests but emit far more on the road.

The greatest problem is with nitrogen dioxide (NO2), a pollutant that inflames the lungs, stunting their growth and increasing the risk of respiratory diseases such as asthma and lung cancer. London has an acute problem with NO2, possibly the worst in the world. Putney high street broke its annual emission limits just eight days into the new year, with Knightsbridge, Oxford Street, Earls Court and Brixton all following suit before the end of January. Across the country, the government estimates 23,500 people die prematurely from NO2 pollution.

Following Ali-Webber on her walk to school is Duncan Mounsor, of Enviro Technology Services, in the company’s brand new electric van, kitted out with £75,000 of the latest pollution monitoring equipment. The existing static network of monitors is vital, he says, but the van allows him for the first time to track the exposure of people in everyday life. “With the van we can really get amidst the hotspots and raise awareness,” he says. As the van crosses Mare Street, the NO2 reading spikes upwards.

Unlike the smoky pollution of the past, NO2 is a hidden killer. “These days you can’t see pollution, you can’t smell it or taste it, so you’d be forgiven for thinking there was no pollution – but there certainly is,” says Monsour.

His next stop is a primary school in Poplar, one of the 1,000 schools in London sitting just 150 metres or less from roads on which at least 10,000 vehicles go past. This school is just 10m or so from the roaring A12, where more than 100,000 HGVs, coaches, construction trucks and cars roar past, while others queue for the nearby exit to the equally busy A13.

Parents start arriving to collect their children, who stream out noisily. Most are walking but some are in cars – one has “Prince on Board” in the rear window – and the NO2 level rises. At a school in Cheltenham, where many children are picked up by car, Mounsor recently measured a tripling in NO2 levels during the school run.

But the more surprising discovery takes place when Mounsor moves off to simulate a car journey home from school. He finds that NO2 levels are 2.5 times higher inside the vehicle than outside. “There’s a concentrating effect of being in a confined space,” he says. Ali-Webber calls it “sweet justice”.

“The public health message is, you can’t hide from air pollution inside a car,” says Ben Barratt, an air quality expert at King’s College London (KCL). “We advise the public to leave the car at home whenever possible. This exposes you and your family to lower levels of air pollution, you’re not contributing to the problem, and you’re also getting the benefits of exercise. That’s tackling three of our biggest public health challenges in one go: air quality, climate change and obesity.”

Facebook Twitter Pinterest Duncan Mounsor, with his van, measuring air quality and pollution outside a school in Poplar, east London. Photograph: Martin Godwin/The Guardian

The parents at the Poplar school spoken to by the Guardian were unaware of the pollution hotspot and the school declined to comment. But the local MP, Jim Fitzpatrick, says: “Air quality is a huge issue. The new cruise ship terminal at Enderby Wharf [which people fear will increase pollution] is a big local issue and reducing emissions from vehicles is another.”

Awareness of the invisible problem is vital, says Barratt: “If you have awareness and concern then people are more likely to accept political strategies which will infringe upon their lives. If politicians come along and say they are going to restrict diesels in their city but the population doesn’t believe there is a problem, they will say no.”

One measure in place in London since 2008 is the Low Emission Zone, which charges highly polluting vans and lorries for entering London. But it has had no impact, according to Ian Mudway, another of KCL’s air pollution experts.

“We found the air quality did not change and when you look at the symptoms of the children [at schools in Hackney and Tower Hamlets], you can show no improvements year on year,” he said. “If anything is a marker that the diesel technology was not working, it was the fact that NO2 did not decrease.”

“I am a concerned parent too,” says Mudway. “The whole of central London is non-compliant with EU standards and I live there. I know it and I take precautions. I always take back routes. I always avoid, if I am with my children, walking down busy congested roads. It’s really important because although the individual risks [of one trip] are small they are additive across time.”

“The life-shortening effects of air pollution are equivalent if not greater than the risks of inactivity and obesity and alcoholism,” he says. “They should be in that bundle.”

Mudway says his litmus test for how seriously authorities take air pollution is if they put new schools, care homes for the elderly and affordable homes for young families by busy roads: “That drives me absolutely insane.” The school in Poplar was rebuilt recently – and moved closer to the heavy traffic on the A12.

Simon Birkett, director of the Clean Air in London campaign group, says: “Children are ultimately defenceless. They can’t vote but they are lumped with the health effects for life.” His research revealed that one-third of London’s schools are close to busy roads and suffer illegal levels of pollution: “That was one of the most upsetting things I ever discovered.”

Facebook Twitter Pinterest Children campaigning for better air in Hackney, East London. Photograph: Kristian Buus

For the solution, Birkett cites the great smog of London, which killed 4,000 people over the course of a few weeks in 1952. It led to the landmark Clean Air Act of 1956, which rapidly improved air quality, but recent decades have seen air pollution climb again with the rise of diesel vehicles. “We are back where we were in a sense,” he says. “There were 4,000 deaths from the great smog and we did something about it. Now it’s 4,000-9,000 deaths a year in London.”

“We need to ban diesels as we banned coal 60 years ago. That is the only way we can comply with World Health Organization (WHO) guidelines,” Birkett says. Paris is planning such a ban for 2020 and a ban on older diesels in Berlin started in 2010. An Ultra Low Emission Zone (Ulez) coming into force in London in 2020 will charge – not ban – more polluting vehicles but only covers 300,000 people in the capital, not the 3 million living in polluted inner London boroughs.

Richard Howard, at the thinktank Policy Exchange, says a complete diesel ban is not feasible. “Diesel vehicles are worse than petrol, but we as a nation have gone out and bought 11m diesel vehicles.”

His report, which found a Londoner’s life expectancy is cut by about 16 months by air pollution, was published in December. It says that, on top of the legal and moral reasons for action, there is an equality case too, as poorer neighbourhoods are worst affected.

“There is a lot going on, but this is a very difficult problem to solve,” Howard says. “There are no silver bullets.” He says action is needed at EU level, to set and enforce tough vehicle emissions standards, at national level, to reform tax incentives for diesels, and at local authority level, to create low emissions zones.

Prof Sir Malcolm Green, founder of British Lung Foundation and an eminent respiratory physician, is in no doubt about the scale of the issue. “London certainly has significant pollution, enough to have effects on health. It is a hidden killer.”

In addition to NO2, particulate matter (PM) remains at double the WHO guideline levels. “It’s like inhaling little particles of tar,” says Prof Green. “They go right down into the lungs and can pass through the membrane into the bloodstream”, increasing the risks of strokes and heart attacks. Though levels in London are close to the higher EU limits for PM, no threshold has yet been established below which harmful effects end.

Facebook Twitter Pinterest In July 2014 researchers from King’s College London found that concentrations of nitrogen dioxide in Oxford Street are the worst on earth. Photograph: Nick Savage/Alamy

But while particulate traps have been fairly effective in cutting this type of pollution from vehicles, standards to cut NO2 emissions have been a huge failure. The Volkswagen scandal exposed devices enabling diesel cars to cheat their way through NO2 emissions tests but most other manufacturers found legal ways to circumvent the regulations, by tuning their cars to emit low levels of NO2 in test conditions but belch out far more when actually on the road.

“The car manufacturers told us their vehicles were very clean, but now we know that was not true,” says Prof Green. “I think the VW fiasco may be a blessing in disguise because it has brought the problem to everybody’s attention. I hope and pray it will cause a step change in the regulation of emissions and I really hope it will be a wake-up call for vehicle manufacturers that they will have to spend serious money and energy on improving the emissions from vehicles. I am absolutely convinced it is doable.”

On Wednesday the EU passed new standards for diesel emissions but these were heavily criticised for being double the legal limit and followed lobbying from the motor industry.

Birkett agrees that the issue is finally getting the attention it deserves and is starting to drive change: “I think we will see some quite dramatic changes by 2020, but anything can go backwards again, so we need to redouble our efforts.”

Back in Hackney, Ali-Webber and her small group of concerned parents are ramping up their campaigning ahead of the London mayoral elections. She wants the Ulez expanded to all inner London boroughs, protecting 3 million people, not just the 300,000 covered by the current plan.

But the air pollution is not only a political one for her, but also very personal. “I said to Zain don’t run around in the playground so much. But he loves football, so what’s he supposed to do?”

How to reduce your exposure to air pollution

The first step in reducing your exposure to air pollution is to be aware of peaks in pollution, via monitoring on websites, Twitter or via mobile phone apps.



On high pollution days, the government recommends adults and children with respiratory problems such as asthma, adults with heart problems and older people should avoid strenuous exercise.

But, across the year, London and other UK cities suffer average levels of air pollution above legal limits, meaning people may want to cut their exposure from day to day.

Air pollution largely comes from road traffic, so avoiding busy roads and junctions will help, especially if the street is flanked by high buildings and there is little wind.

“Walking along back roads rather than beside busy roads will reduce your exposure,” say the experts at KCL. One recent study also showed that air pollution can be a third lower on the inside of the pavement, compared to the kerbside.

Perhaps surprisingly car drivers can be exposed to higher levels of air pollution inside their vehicle than on the pavement, suggesting that walking or cycling could be healthier. For those who need to drive, the British Lung Foundation (BLF) recommends keeping the windows closed and recycling the air in the car, rather than keeping air vents open.

The BLF also says: “There is little evidence to recommend the use of face masks. Wearing one can be uncomfortable and can make breathing more difficult.”

Choosing when to exercise may be important, say KCL: “The faster you breathe the more airborne pollutants are delivered to your lungs. By changing your exercise routine [to times or places with lower pollution] you can reduce your exposure.”

KCL also notes that diet is believed to help protect against pollution: “A study conducted in Mexico City has shown that children eating more antioxidants, from fresh fruit and vegetables, are better protected against the oxidative effects of ozone and other ambient pollutants.”