The 800 roads in Britain with dangerous levels of air pollution

Britain’s most dangerous roads for air pollution levels have been revealed – and more than 75% are in London.

Analysis by environmental legal firm ClientEarth has emerged following a landmark inquest that ruled air pollution contributed to the death of a nine-year-old asthmatic girl Ella Kiss-Debrah.

Ella, who lived 80ft from London’s congested South Circular Road in Lewisham, endured almost 30 hospital admissions and countless seizures before she died of a fatal asthma attack in 2013. 

Data released by ClientEarth has laid bare the state of pollution on London’s roads, as 603 streets made it onto the list of 800 nationwide.

The Marylebone Flyover, near Edgware Road tube station, was revealed to be the worst spot in the country with average annual nitrogen dioxide levels measuring at  77mcg per cubic metre. EU limits are currently set at 40mcg. 

Birmingham was the next highest for polluted roads – but fell far lower than London with just 15, followed by Manchester with 13.

This map collated by the London Air Network shows daily maximum index values of nitrogen dioxide across the capital. 1-3 is low, 4-6 is moderate, 7-9 is high and 10 is very high 

Nitrogen dioxide levels in London have been decreasing in all zones and site types since 2016

Year Roadside CentralBackground CentralRoadside InnerBackground InnerRoadside OuterBackground Outer

The cities and towns featured in a list of Britain’s 800 most polluted-roads  

London – 603

Birmingham – 15

Manchester – 13

Glasgow – 12

Leeds – 10

Stoke-on-Trent – 10

Newcastle-upon-Tyne – 8

Sandwell (West Mids) – 6

Gateshead – 6

Cardiff – 6

Sheffield – 6

North Lanarkshire – 5

Havant (Hants) – 4

Nottingham – 4

Bristol – 4

Bolton – 4

Surrey Heath – 4

Oldham – 4

Middlesbrough – 3

Rushmoor (Hants) – 3

South Lanarkshire – 3

Belfast – 3

Guildford (Surrey) – 3

Reading – 3

Kirklees (West Yorks) – 3

Bournemouth – 3

Stockport – 3

North Tyneside – 3

Solihull – 2

Southampton – 2

Basildon – 2

Rotherham – 2

Liverpool – 2

Walsall – 2

Coventry – 2

Edinburgh – 2

Flintshire (North Wales) – 2

Trafford (Greater Manchester) – 2

Wolverhampton – 2

Rhondda Cynon Taf – 2

Renfrewshire – 2

Derby – 2

County Durham – 1

Bolsover (Notts) – 1

Swansea – 1

Tameside (Greater Manchester) – 1

Newport (South Wales) – 1

Sefton (Merseyside) – 1

Portsmouth – 1

Fareham (Hants) – 1

New Forest (Hants) – 1

Neath Port Talbot – 1

Spelthorne (Surrey) – 1

Aberdeen – 1

Crawley – 1

Slough – 1

Southend-on-Sea – 1

Newcastle-under-Lyme (Staffs) – 1

Leicester – 1

Plymouth – 1


Katie Nield, of environmental law charity ClientEarth, told The Mirror: ‘What this shows is that there’s a possibility of making this link in a court of law for the many other people who suffer as a result of breathing dirty air.

‘Making this link now may seem like a bit less of a leap than it did before this decision.’ 

London introduced an Ultra Low Emission Zone in April last year, which saw a 13 per cent fall in nitrogen dioxide levels in 2019 from 2018.  

Key pollutants in the air are from vehicles are nitrogen dioxide and particulate matter (PMs). While pollutant levels have fallen in recent years, ClientEarth found 33 out of 43 UK air quality zones still have levels of nitrogen dioxide that are above legal limits.

While particulate matter pollution is within legal limits, it is still above World Health Organisation guidelines and there is concern that it is not being brought below this. 

However it added that traffic and pollution levels have since been back on the rise in many towns and cities, and the temporary dip should not be an excuse for inaction.

Speaking about the London data, its campaigns manager Andrea Lee told MailOnline: ‘For decades really there was very little action on air pollution.

‘In 2014 air pollution levels in London were three times over the legal limit, and this highlighted the extent of the problem cities like London were facing.

‘The improvements were seeing now really stem from mayors recognising they need to act. Back in 2015, Mayor Boris Johnson confirmed the Ulez, which under his plans was going to come in 2020.

‘Luckily we were able to convince the current mayor that the problem was so urgent that we really couldn’t wait that long. 

‘After public consultation it was decided the Ulez would be brought in 18 months earlier, and it was also preceded by other measures to help clean up the bus fleet – zero emission buses on the road.’

The Ulez operates 364 days a year within the same area of Central London as the Congestion Charge. Most vehicles need to meet Ulez emissions standards or their drivers must pay a daily charge to drive within the zone, which is £12.50 for most motorists but £100 for heavier vehicles.

Ms Lee also put the fall down to ‘general talk and awareness raising, to make people realise things like diesel vehicles really don’t belong in towns and cities because of the pollution they cause’.

She added: ‘This helped take London from three times over the limit in 2013 to just over two times over, but it’s obvious more needs to be done.’

Ms Lee suggested this could be helped be making electric cars more accessible and affordable, and further investment in public transport.

ClientEarth said the UK is not meeting legal limits of nitrogen dioxide pollution, where the annual average cannot exceed 40µg/m3 (micrograms per cubic metre of air).

And there are concerns over clean air zones which deter the most polluting vehicles from entering the most polluted parts of towns being pushed back due to the crisis. 

Nitrogen dioxide and particulate matter pollution were both cited by the coroner in Ella’s inquest yesterday, and Ms Lee was asked which is more dangerous to health.

YearMaximum modeled annual mean concentration (µg/m3)No. of times over annual limit value (40µg/m3)Maximum modeled annual mean concentration (µg/m3)No. of times over WHO guideline of 10µg/m3 (NB annual limit value = 25µg/m3)Maximum modeled annual mean concentration (µg/m3)No. of times over WHO guideline of 20µg/m3 (NB annual limit value = 40µg/m3)
Average nitrogen dioxide (NO2) and particulate matter (PM2.5 and PM10) in London are shown

Average nitrogen dioxide (NO2) and particulate matter (PM2.5 and PM10) in London are shown

But she told MailOnline: ‘It’s hard to say which pollutant is more important than the other, and with the inquest into Ella’s death it was very specific to her particular condition. The coroner recognised this soup of toxic air that Ella and all of us are exposed to needs to be dealt with.

‘Nitrogen dixoide is seen as more of a localised pollutant so it means it’s really most concentrated near the source, which is why it’s so important in terms of road transport.

‘But in the UK because it’s such a windy country, we benefit because it helps to sweep it away. PM is a mixture of liquid particles and solid particles with various different sources, from combustion and even agriculture.

‘Because of the way it behaves, the particles can be a 20th of the width of a human hair. They are harder to disperse because of the way they behave.

Ella Kissi-Debrah is believed to be the first person in the UK to have air pollution listed as the cause of death on their death certificate, following the ruling by a coroner at a second inquest

Ella Kissi-Debrah is believed to be the first person in the UK to have air pollution listed as the cause of death on their death certificate, following the ruling by a coroner at a second inquest

The nitrogen dioxide concentration across London is shown for 2013, the year when Ella died

The nitrogen dioxide concentration across London is shown for 2013, the year when Ella died

The difference between nitrogen dioxide and particulate matter


  • Gas is produced along with nitric oxide (NO) by combustion, which are together referred to as NOx
  • 80% of NOx emissions in areas where the UK is exceeding NO2 limits are due to transport
  • Largest source is from diesel light duty vehicles – cars and vans
  • Others include power generation, industrial processes and heating
  • Short-term exposure to high NO2 levels that can cause inflammation of the airways leading to coughs
  • It is also linked to reduced lung development and respiratory infections in early childhood 
  • Studies associate it with reduced life expectancy, although it is unclear whether this is caused by NO2 or other pollutants at the same time 


  • Generic term refers to mixture of solid and liquid particles 
  • Some are emitted directly (primary PM), while others are formed in the atmosphere through chemical reactions (secondary PM)
  • Composition depends on geographical location, emission sources and weather
  • Main sources of man-made PM are the combustion of fuels by vehicles, industry and domestic properties
  • Natural sources include wind-blown soil and dust, sea spray particles, and fires involving burning vegetation
  • Particles larger than 10µm are mainly deposited in the nose or throat, but those smaller than 10µm pose the greatest risk because they can be drawn deeper into the lung
  • Long-term exposure to PM increases mortality from cardiovascular and respiratory diseases 

‘They tend to spread out more and there’s less aviation in terms of localised sources and more background levels. They can still be more concentrated in certain areas. 

Experts have previously claimed pollutants play a role in the equivalent of 40,000 early deaths a year in the UK.

Air pollution can trigger strokes, heart and asthma attacks, increase the risk of hospitalisation or death, cause cancer and can stunt lung growth in children.

It has been linked to premature births, damage to children’s learning and even dementia.

Older people, the young and those with chronic illnesses are more vulnerable to air pollution and those on low incomes and from ethnic minorities are disproportionately affected by it.

Legal limits for pollution to protect people’s health should have been met by 2010.

But across the UK levels of nitrogen dioxide still breach the rules today, and while particulate matter pollution is within legal limits, it is still above World Health Organisation guidelines.

The Government has lost three court actions in the last decade brought by ClientEarth, over its failure to tackle the problem of illegally dirty air.

The court cases have prompted requirements for action by local, regional and devolved governments – and a new clean air strategy last year to tackle the problem.

Mr Khan claims that since he took office in 2016, nitrogen dioxide levels have reduced in Central London by a rate five times greater than the national average.

In 2016, London’s air exceeded the hourly legal limit for nitrogen dioxide for more than 4,000 hours – but last year this fell to just over 100 hours.

In 2019, 33 of the UK’s 43 air quality zones were still above the legal limit for nitrogen dioxide, analysis of government figures by ClientEarth revealed, including London, Manchester, Sheffield, Glasgow, Belfast and Bristol.

Nitrogen dioxide and PMs come from sources such as road traffic and domestic heating systems including boilers and wood burners, with vehicles – particularly diesel vehicles – a key part of the problem.

In the long-term, the shift to electric vehicles and heating systems will help, though particle pollution is still caused by tyres and brakes, but those improvements are still many years off.

The annual average UK concentrations of nitrogen dioxide have been mostly falling since 1997

The annual average UK concentrations of nitrogen dioxide have been mostly falling since 1997

In 2019, 33 of the UK's 43 air quality zones (above) were still above the legal limit for nitrogen dioxide, analysis of government figures by ClientEarth found. Full details are in the below table

In 2019, 33 of the UK’s 43 air quality zones (above) were still above the legal limit for nitrogen dioxide, analysis of government figures by ClientEarth found. Full details are in the below table

Traffic’s role in nitrogen dioxide emissions was highlighted earlier this year when levels of the pollutant fell in many cities and towns as people stayed home and roads emptied of vehicles in lockdown.

But the benefits were short-lived, as pollution has already returned to pre-pandemic levels or even higher in the majority of towns and cities.

And evidence suggests that air pollution could play a role in at least some of the deaths from Covid-19, compounding its other health impacts.

As people continue to stay away from public transport, efforts to encourage active travel such as walking and cycling in towns and cities – which would also benefit health and reduce the pollution that drives climate change – have been mixed.

Low traffic neighbourhoods and cycle lanes have been installed, but a backlash from some motorists has seen them removed in places such as Kensington High Street.

Campaigners want to see measures to speed up the use of electric vehicles, including e-bikes, and the introduction of clean air zones, which charge drivers of the most polluting vehicles in certain areas.

Greater London Urban Area771.9
South Wales (includes Newport)641.6
Eastern (includes Cambridge and Norwich)571.4
Glasgow Urban Area561.4
West Midlands Urban Area (includes Birmingham)521.3
West Midlands521.3
The Potteries (includes Stoke on Trent)511.3
Southampton Urban Area511.3
Edinburgh Urban Area501.3
Teesside Urban Area491.2
North East491.2
West Yorkshire Urban Area481.2
Sheffield Urban Area481.2
South East (includes Bath)481.2
Yorkshire Humberside481.2
Liverpool Urban Area471.2
Greater Manchester Urban Area461.2
Portsmouth Urban Area461.2
North West Merseyside461.2
Central Scotland461.2
Belfast Urban Area451.1
Reading/Wokingham Urban Area441.1
North Wales441.1
Nottingham Urban Area431.1
East Midlands431.1
Southend Urban Area431.1
Bristol Urban Area431.1
Bournemouth Urban Area421.1
Cardiff Urban Area421.1
South West421.1
North East Scotland411
Leicester Urban Area401
Kingston upon Hull401
Swansea Urban Area401
Birkenhead Urban Area391
Preston Urban Area381
Scottish Borders310.8
Northern Irelands290.7
Blackpool Urban Area260.7

But efforts to bring in clean air zones have been delayed by the pandemic in some areas.

Part of the lack of urgency on the issue may be because, unlike the old pea-souper smog events that prompted the UK’s first Clean Air Act to clean up pollution in the 1950s, today’s pollutants are an invisible killer.

But now the fatal impact of pollution has a human face – an active nine-year-old girl who died because of the toxic air she was surrounded by. 

Yesterday, inner South London coroner Philip Barlow concluded in a landmark ruling: ‘Ella died of asthma contributed to by exposure to excessive air pollution. The whole of Ella’s life was lived in close proximity to highly polluting roads.’

There is now likely to be growing pressure on the Government to adopt the stricter World Health Organisation pollution guideline limits in the wake of the ruling.

The Government has said it will set legally binding targets for fine particulate matter or PM2.5, the most harmful pollutant, alongside a further long-term air quality target under the new Environment Bill. 

Previously healthy schoolgirl Ella – who was first diagnosed with asthma in 2010 – is the first person in the UK to have ‘air pollution’ listed as a cause of death on her death certificate.

The ruling marks the culmination of a seven-year battle by her mother Rosamund, 64, to have the role of toxic traffic fumes in her daughter’s death recognised.

Welcoming the coroner’s conclusion, the former teacher said the family finally had the ‘justice’ that the gifted schoolgirl from Lewisham ‘so deserved’.

But she added her efforts were ‘far from over’ as she was fighting for other children still breathing in toxic air. She said she had no interest in playing a ‘blame game’ but wanted to focus on a public awareness campaign on the risks posed by pollution.

Miss Kissi-Debrah hopes to work with Arnold Schwarzenegger after her campaign was praised by the Hollywood star.

After a second inquest lasting two weeks, Dr Barlow concluded Ella was exposed to excessive levels of nitrogen dioxide and particulate matter pollution – mainly from traffic emissions – her whole life. ‘Air pollution was a significant contributory factor to both the induction and exacerbations of her asthma,’ the coroner said.

‘During the course of her illness between 2010 and 2013 she was exposed to levels of nitrogen dioxide and particulate matter in excess of World Health Organisation guidelines.

Her mother Rosamund Kissi-Debrah (pictured arrive at Southwark Coroner's Court yesterday) described her nine-year-old daughter Ella as 'the centre' of her family's world

Her mother Rosamund Kissi-Debrah (pictured arrive at Southwark Coroner’s Court yesterday) described her nine-year-old daughter Ella as ‘the centre’ of her family’s world

‘The principal source of her exposure was traffic emissions. During this period there was a recognised failure to reduce the level of nitrogen dioxide to within the limits set by EU and domestic law, which possibly contributed to her death.’

He said her mother had not been warned of the pollution’s health risks, which would have led to her taking preventive steps – such as moving home – and helping to prevent her death.

Making legal history, Dr Barlow recorded Ella’s medical cause of death as ‘1 a) acute respiratory failure, 1 b) severe asthma, 1 c) air pollution exposure’.

It comes after Miss Kissi-Debrah won a High Court battle for a second inquest when new evidence revealed pollution near her home was at unlawful levels before her daughter’s death.

Ella lived 80ft from the South Circular in Lewisham, South East London (pictured yesterday)

Ella lived 80ft from the South Circular in Lewisham, South East London (pictured yesterday)

A previous ruling from 2014, which concluded Ella died of acute respiratory failure possibly triggered by ‘something in the air’, was quashed by a judge.

Yesterday Miss Kissi-Debrah said that while she was pleased with the outcome she was ‘sad’ that she was never able to tell Ella why she had been so poorly.

Professor Sir Stephen Holgate, author of the report that quashed the initial findings of the first proceedings, said in his evidence to the inquest that Ella was a like a ‘canary in a coalmine’.

Labour MP Geraint Davies, chairman of the All-Party Parliamentary Group on Air Pollution, said the case may establish ‘civil liability’ – the basis for a damages claim to local or national government as they have a ‘duty of care to reduce air pollution to safe levels and they have failed’.

More action is needed to tackle air pollution, says Ella’s mother

The mother of a nine-year-old girl who suffered a fatal asthma attack said she has won justice for her after a coroner ruled air pollution contributed to her death.

But with other children still exposed to illegal levels of air pollution, the ‘matter is far from over’, Rosamund Kissi-Debrah said.

Ella Kissi-Debrah is believed to be the first person in the UK to have air pollution listed as the cause of death on their death certificate, following the ruling by assistant coroner Philip Barlow at a second inquest into her death.

Ella, who lived 80ft (25m) from the South Circular Road in Lewisham, South East London, died in February 2013, having endured numerous seizures and made almost 30 hospital visits over the previous three years.

A previous inquest ruling from 2014, which concluded Ella died of acute respiratory failure, was quashed by the High Court following new evidence about the dangerous levels of air pollution close to her home.

Speaking at a press conference after the new inquest ruling, Ms Kissi-Debrah said her campaign for a second inquest had been about getting air pollution on her daughter’s death certificate. But it was also about protecting other children still exposed to high levels of air pollution in London, she said.

Ms Kissi-Debrah said her daughter would have cared about the suffering of other children, and she wanted her legacy to be a new Clean Air Act and for governments around the world to take the problem seriously. She called for a public information campaign with clear messages to educate people on the damage air pollution is doing.

In his conclusions, Mr Barlow said it was not disputed that in the period between Ella being diagnosed with asthma and dying, the whole of the UK was in breach of its obligations to comply with the nitrogen dioxide limits set under both EU and domestic law.

He said: ‘As I understand it, London has still not reached compliance with those limits.’

After the inquest, Ms Kissi-Debrah told reporters: ‘Yes, this was about my daughter, getting air pollution on the death certificate which we finally have, and we’ve got the justice for her which she so deserved.

‘But also it’s about other children still, as we walk around our city of high levels of air pollution, and I hope you heard what the coroner said that there are still illegal levels of air pollution now, as we speak, so this matter is far from over.’

After the coroner also ruled Ella’s mother had not been given information on the health risks of air pollution that might have helped prevent Ella’s death, Ms Kissi-Debrah said she was ‘not going to sit here now and regret things that have gone on’.

She said she hoped there would be more information available in the future at GP surgeries, hospitals and on leaflets, so people could make informed decisions.

Ms Kissi-Debrah said: ‘When you balance it out, yes the information should have been there, it wasn’t, but maybe we can make sure the information is there for the future.’

And she said: ‘There needs to be a whole education about air pollution and exposure to air pollution. I still think there’s a lack of understanding about the damage it does to young lungs, especially that are not truly formed. I would rather, going forward, we do a public awareness campaign, teach the population about the damage air pollution is doing, rather than a blame game.’

The messages on air pollution need to be concise and very clear, she said.