Swiss Cottage residents say their street has become so polluted that they cannot open their windows.

They claim road changes, intended in part to improve air quality, have instead seen the area paralysed by heavy traffic.

Transport for London (TfL) will decide soon whether to make the changes permanent.

According to ward councillor Shiva Tiwari, TfL recently indicated that “they have no intention of removing” the new layout.

TfL said it could not comment, due to the impending election.

Residents had hoped pollution data would support their campaign to undo the road changes.

But here is a problem - on Camden Council’s website, the data is missing.

Ham & High: Traffic on Greencroft Gardens in Swiss CottageTraffic on Greencroft Gardens in Swiss Cottage (Image: Polly Hancock)

‘Ludicrous’

Over 41 years, Rosemary Coleman, 79, has watched Greencroft Gardens get gradually busier.

The road has “always been a bit of a rat-run", particularly during roadworks on nearby Finchley Road, she said.

But in the last year, she added, there has been a significant leap in traffic.

“Even indoors, I can smell the fumes,” she said. “It’s horrible.”

Last year TfL closed the Finchley Road bus lane to create more space for pedestrians to socially distance.

The next lane became a replacement bus lane.

“They left one lane for traffic on the main arterial road out of London,” said Rosemary. “It’s ludicrous.”

Ham & High: Resident Rosemary Coleman said she could smell the fumes even inside her home.Resident Rosemary Coleman said she could smell the fumes even inside her home. (Image: Polly Hancock)

According to TfL’s website, the scheme was designed to stop roads becoming gridlocked and improve air quality.

Residents say it has done neither.

‘Terrified’

Cllr Tiwari said the closure has “turned large swathes of Finchley Road into a smoggy and virtually permanent traffic jam”.

“I am not surprised to now hear from residents that it is worsening air quality where they live too,” he added.

Dr Jo Davis first noticed traffic building in Greencroft Gardens last summer.

As the problem worsened, she started asking drivers where they were coming from.

“They would say: ‘We’ve been routed this way.’” she said. “They were following their satnavs, which were trying to avoid the traffic on Finchley Road.”

Initially the traffic jams started at around 4.30pm, but Dr Davis says she is having to close her windows earlier and earlier.

Last week it was jammed by 2.45pm, she said.

She said she is "terrified" for her son, who has an underlying health condition.

“I don’t even know if we are safe in the garden,” she said. “I’m trying not to be paranoid, but you can smell the traffic. There’s dirt and dust coming into the house.”

Ham & High: Dr Jo Davis said she was 'terrified' of the pollution's potential impact on her son.Dr Jo Davis said she was 'terrified' of the pollution's potential impact on her son. (Image: Polly Hancock)

The Data

The six-lane Finchley Road is one of the most polluted places in Camden.

For years, the council has monitored Nitrogen Dioxide (NO2) there.

The toxic gas, emitted by vehicles, can cause respiratory illness and reduce life expectancy.

The legal limit for NO2 is 40 microgrammes per cubic metre of air. Levels on Finchley Road breached that limit for years.

In January 2017, one monitor gave an average reading of 106.71 microgrammes – the worst anywhere in Camden that year.

Three monitors in Finchley Road gave average readings far over the legal limit for every month in 2017.

Data was incomplete for both 2018 and 2019, but every captured month was far beyond the legal limit.

Camden Council said monthly average concentrations were not the most accurate measure for air pollution.

Ham & High: Traffic on Greencroft Gardens.Traffic on Greencroft Gardens. (Image: Polly Hancock)

What now?

On Camden Council’s website, NO2 monitoring in Finchley Road cuts out after January 2020 – which was 52% over the limit.

The council said it monitored Finchley Road by two methods – automatic monitoring and diffusion tubes.

The diffusion tube data is what the council usually publishes and is not available “for much of 2020”, it said - “an indication that our monitoring equipment has been tampered with”.

The council said it does have “full data” on NO2 pollution in Finchley Road from automatic monitoring.

With this data, residents may be able discern whether the gridlock resulting from the Finchley Road closure has increased toxic fumes – as cars sat still in traffic can emit twice as much pollution as when they are moving – or has reduced them by displacing traffic to other areas.

Ham & High: Residents of Greencroft Gardens NW6 say traffic using the road has become unbearable.Residents of Greencroft Gardens NW6 say traffic using the road has become unbearable. (Image: Polly Hancock)

Residents are now lobbying for air monitoring in Greencroft Gardens.

Camden Council said: “We will work closely with TfL to understand the monitoring being undertaken for the scheme and the impacts on our surrounding road network.”

It added that all automatic monitoring stations in Camden had recorded an overall improvement in NO2 levels from 2019 to 2020, during which repeated lockdowns imposed bans on non-essential travel.