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Bishop’s Stortford’s air pollution blackspot Hockerill could be the first in the country to be cleaned by Hertford firm Pollution Solution’s Roadvent technology





Bishop’s Stortford’s traffic pollution blackspot at Hockerill could be the first site in the country to be cleaned by a Roadvent.

Hertford company Pollution Solution is behind the innovative technology which claims to significantly improve air quality by pulling dirty vehicle emissions into slots in the highway and cleaning at the roadside.

Hockerill junction – where Stansted Road, Dunmow Road, London Road and Hockerill Street intersect – has been a cause of concern since 2007, when it became the first air quality management area (AQMA) in East Herts. It was followed by Gascoyne Way, Hertford, in 2010 and London Road, Sawbridgeworth, in 2015.

Traffic queues along Dunmow Road to the Hockerill lights
Traffic queues along Dunmow Road to the Hockerill lights

The legal annual mean limit is 40 micrograms of nitrogen dioxide (NO2) per cubic metre of air (µg/m3), but levels of more than 70 µg/m3 were recorded at Hockerill.

Hertfordshire County Council is responsible for highways and a spokesman confirmed: “We are investigating the possibility of installing a pollution filtering system at the Hockerill junction as one contribution to improving air quality at this location.

“This work is at an early stage, although initial surveys suggest this might be a suitable location. There is a lot of work to be done before any system can be installed, but it is something we are actively exploring.

Roadvent. Picture by Pollution Solution
Roadvent. Picture by Pollution Solution

“One of our sustainability ambitions is for cleaner air for everyone, and whilst we are working to reduce harmful emissions in the first place – for example, our vehicle anti-idling campaign to minimise traffic-based emissions – we are keen to reduce the level of pollutants in ‘hot spots’.”

East Herts Council is responsible for air quality and published an action plan earlier this year, setting out its improvement strategy.

A spokesman said: “We are in talks with Hertfordshire County Council on the possibility of installing a Roadvent at Hockerill junction. Meetings between East Herts and the county council to discuss this are planned for later this month.

“We welcome any ideas that would help tackle air quality issues at the junction and look forward to updating residents about progress on the various initiatives in our new Air Quality Action Plan.”

Hockerill junction air pollution protest
Hockerill junction air pollution protest

The Roadvent captures and cleans emissions like a household vacuum cleaner and claims to reduce roadside pollution exposure by up to 91%.

It traps exhaust gases as well as brake and tyre dust – including pollutants such as nitric oxide (NO) and NO2 and inhalable particulate matter 2.5 microns or less in diameter (PM2.5) and 10 microns or less (PM10).

The dirty air is cleaned as it passes through an electrostatic precipitator, activated carbon and HEPA filters. Once the process is complete, clean air is released from the top of the roadside air cabinet.

Stock image
Stock image

As well as Herts County Council, Lewisham Borough Council is keen to install Roadvent near a school and has received £132,532 from Sadiq Khan’s Mayor’s Air Quality Fund. The authority has said it hopes to complete the project by the autumn.

Entrepreneur Thomas Delgado came up with the Roadvent idea in 2014 and has been developing the technology with his team ever since. He was happy to answer Indie questions about his invention.

Traffic queues along Stansted Road to the Hockerill lights
Traffic queues along Stansted Road to the Hockerill lights

Is a Roadvent in operation anywhere in the country, outside of a testing or demonstration environment?

“At present, no. We have recently launched the product and a significant amount of time has been invested in showcasing the system to interested parties.

“The Hertfordshire or Lewisham installation will be the first of its kind. We are awaiting updates on timescales before we can confirm who will be first.”

Mr Delgado demonstrates his device at UTAC Millbrook Proving Ground, Bedfordshire, and told the Indie his company had already planned installations with four more parties – including one outside the UK – but the details were confidential.

How does Pollution Solution prevent the Roadvent from becoming clogged with dirt and debris?

Traffic queuing back along Stansted Road from the Hockerill junction
Traffic queuing back along Stansted Road from the Hockerill junction

“The road-based slots have a built-in ‘mesh’ which stops large items (like leaves, cigarette butts etc) from entering the channel.

“Roadvent is active only when vehicles are present. When they are not, the system turns off and any dirt/debris simply blows away.

“Any small dirt and debris that enters the system is flushed away in the same way that the roadway drainage systems currently handle this.”

How does Roadvent deal with water, ice and snow?

“Roadvent is designed to ingest and drain water and snow from the road surface – it is also connected to the main water sewer.

“Roadvent has been developed by re-engineering pre-existing products, one of which is the slot drains which we install into the carriageway.

“These drains have traditionally been used as water drainage channels which are self-flushing, self-cleaning and have a natural gradient inside of them to ensure efficient drainage.

“Roadvent creates a vacuum to capture exhaust, brake and tyre emissions but also doubles up as a normal drainage system. Of course, in the instance of significant snow or rainfall, the system has an inbuilt sensor which ensures the system doesn’t activate.”

How much energy does the Roadvent require to work effectively?

“The most efficient way to activate and run Roadvent is via a vehicle activation sensor. As you can imagine, traffic volumes vary greatly depending on location, but for example, if Roadvent was to run constantly for 60 minutes, it would use around £5 worth of electricity. However, this would be very unusual (to run the system continuously).

“A more common way to run the system is for short bursts (four to five minutes) while vehicles are slow-moving or idling at a junction, for example at traffic lights.”

Roadvents are available in 20m modules and designed to have a lifespan of more than 20 years.

Mr Delgado said: “This lifespan calculation is on the back of the main component – the channel in the road – having been used in other heavy-duty use cases for over 20 years. Some examples include Formula 1 race tracks, car parks, roads, motorways, airports etc.”

He added that the funding for the Lewisham contract did not indicate a typical Roadvent cost as “there is a large amount of community engagement, research and communication involved in that project”.

Hertford and Stortford MP Julie Marson
Hertford and Stortford MP Julie Marson

His invention has impressed Hertford and Stortford’s Conservative MP Julie Marson. After a meeting with the business, she claimed on social media: “Since I was elected, I’ve tried to find a measure that will improve air quality at the Hockerill lights in Bishop’s Stortford, one of the worst areas around for pollution.

“After exploring numerous options, I am clear that I want to see a Roadvent installed at the site. I am confident in its efficacy and want to see it installed at site as soon as possible.”

Cllr Richard Roberts
Cllr Richard Roberts

She claimed she had been working with Hertfordshire County Council’s Conservative leader, Cllr Richard Roberts, to progress the plan.

In response to her Facebook post, town and East Herts district councillor Chris Wilson asked her to work with local members, regardless of party, to find a solution to Hockerill. He holds a Bishop’s Stortford All Saints seat for the Liberal Democrats on East Herts Council and is also its executive member for resident engagement.”

Cllr Chris Wilson
Cllr Chris Wilson

He told her: “This should not be a political issue, and I would welcome your input and influence in trying to solve this issue.”

However, Mrs Marson did not respond and Cllr Wilson told the Indie: “Disappointingly, Mrs Marson has still failed to contact me regarding this vital issue for my ward’s residents.

“What’s more, East Herts Council has a statutory responsibility to address air quality issues and it would therefore be vital for Mrs Marson to work with members of that council on any potential solutions to the long-standing issues at Hockerill.

Stortford Lib Dems protesting about pollution at Hockerill.
Stortford Lib Dems protesting about pollution at Hockerill.

“Instead, she has issued publicity photos with councillors of her own party, past and present, who neither represent the wards in question nor control East Herts.

“I would again urge her to work with those of us responsible for this issue, including the local county councillor and the district councillor responsible for environmental sustainability. I can safely speak for all of us when I say that our doors are always open and we would be delighted to find a solution to this public health issue, regardless of who helps solve it.

“Finally, I would note that whilst the potential remedy Mrs Marson cites may be very promising in finding a way to reduce air pollution, it can do nothing to stop Stortford residents continuing to suffer from dreadful traffic congestion at Hockerill and nearby.

“Once again, I would restate my willingness to work with her on this and any issue to the benefit of residents.”



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