Unproven and "unbelievable": why is Lewisham rolling out Roadvent?

Lewisham air quality officers told councillors in September that they had been awarded a grant of £132,532 to install Roadvent, "an innovative pollution mitigation measure".

They described it as sucking pollution from vehicle tailpipes, then sending it through filters in cabinets installed at the side of the road.

They said the device would be located near a school or nursery in a highly polluted area.

"A bit unbelievable"

Councillor Liam Curran, the sustainable development scrutiny committee chair said: "It seems a bit unbelievable .. I'm trying to understand how it can be big enough to be effective," and was promised more information.

Salamander was also trying to understand this innovation and assess its viability.

We raised a Freedom of Information (FOI) request asking how Lewisham council came to choose Roadvent and for evidence of its performance.

Solution Pollution Holdings, a firm that reports a single employee, director Thomas Delgado, approached Lewisham council in February 2023.

When funding from the Mayor's Air Quality Fund (MAQF) was announced in December 2023, Pollution Solution helped officers bid for funds for the 3 year "trial".

MAQF is providing £132,532 while the council is providing match funding of the same amount, which includes £93,392 from Parking Services and 30 weeks of officers' time, valued at around £39K.

Delgado's firm is being paid £223,256 from public funds.

"Rolling it out, having seen a graph in a lab"

But we found a worrying lack of evidence that Delgado's bright idea works. The "technical specification" is a high level sales brochure, with a single graph extracted from a report from a vehicle emissions testing centre.

The graph immediately raises questions about how and whether this relates to real world traffic pollution.

"Lab testing" at a test centre should be followed by many other stages of testing, before a product is deemed fit to be installed in public. But Delgado seems to have skipped them and started touting his idea around councils in 2022.

Air quality scientist Dr Pete Knapp said: "They seem to rolling it out based on having seen a graph in a lab, there is no evidence that this is what you'd see in the real world".

The council told us that it had also relied on endorsements from academic institutions, that appear in the same brief document.

But the statements are from individual academics, one emeritus (retired), who appear to have attended a demonstration in 2022, not endorsements from institutions.

The quote from Professor Frank Kelly of Imperial says that "early tests" for Roadvent were "promising" for reducing NO2.

The firm has provided no evidence of the rigorous testing that a new innovation should have before it is unleashed on the public.

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Claim to "reduce roadside pollution by 91%" unproven

Pollution Solution depends heavily on its claim that Roadvent "reduces roadside levels of air pollution by 91%".

But the graph that the firm repeatedly shares raises a host of questions about the validity of the test result in the real world.

Air quality experts that we consulted raised a series of scientific questions about the data in the graph, the monitoring that will be required, and further requirements for testing.

Technology readiness levels

Technology innovation generally emerges from incubation hubs, which usually have strong links with universities.

Entrepreneurs progress their innovations through Technology Readiness Levels (TRLs) from TRL1 to TRL8, at which point the product is "fully developed and tested, proving its meets performance requirements" and ready for deployment.

Investment from private or public funders is tightly geared to the level that the innovation has achieved.

The testing which Lewisham council referred Salamander to is lab testing (TRL4) at best.

Roadvent is far from being ready to be rolled out, which raises questions. Why has it failed to find the investment to take it through higher levels of testing?

Impact for disabled people and those with buggies

The trial requires large filter cabinets on pavements, raising immediate issues for pedestrians, including disabled people and people with buggies. It seems this has not been considered.

There is also no evidence that the safety of the vent had been assessed, eg to cyclists (could they get a wheel caught?) or even to small wildlife.

Pollution Solution makes no reference to accessibility or health and safety issues on the pavement or road.

Unless Transport for London steps in first, Lewisham residents will be the guinea pigs.

Life cycle impacts unknown

Roadworks involve digging up the road surface and replacing tarmac, using diesel equipment, and cause sudden and extreme spikes of air pollution.

Lewisham council ignored our question about the local impact of the roadworks for the Roadvent trial, but told us it planned to "install the system during the school holidays to minimise disruption in the area".

But there are serious questions about Roadvent's life cycle impacts.

For any initiative, but particularly one that claims to be positive for the environment, life cycle analysis (LCA) is fundamental. This provides the cradle to grave accounting of whether the benefits of the product outweigh its environmental impacts.

Our experts raised a host of questions which the "technical specification" leaves unanswered.

Examples included: How often will the HEPA filters become saturated and need replacement? What is their environmental cost, how will they be disposed of?

How much electricity will be needed to apply the suction and to run the filter cabinets? What are its carbon emissions and air pollution impact, or opportunity cost?

At a demonstration in 2022, a Roadvent marketing spokesperson responded to a question about the financial cost of maintenance saying: “We are enabling councils to offset maintenance costs via the revenue generated from display advertisement on the roadside air cabinet’s digital screens.”

Lewisham council told us they could not comment on life-cycle impacts before the trial. But it is Pollution Solution's responsibility to confirm the life cycle impacts of it's product, not the council's.

If the firm cannot confirm the benefits and the impacts of Roadvent, this raises further questions about the council's decision.

Toxic road run-off

Around the UK, awareness of the dangers of toxic road run off is rising, with evidence showing that pollution in rainwater that drains from roads is toxic, carcinogenic and contains heavy metals, hydrocarbons and microplastics.

In most areas across England, this flows directly into rivers.

We were advised that the Roadvent system splits the air and water intakes, so it will not increase toxic road runoff.

However, there was no explanation of how the system would separate run off from NO2 and PM2.5, and no evidence to support the claim or that the product has been tested during rain.

Petrol and diesel representation

Pollution Solution demonstrated Roadvent in 2022 to the Westminster Commission for Road Air Quality (WCRAQ), which supports the All-Party Parliamentary Group (APPG) on air pollution.

APPGs are a way of bringing together MPs, commercial lobbyists and NGOs and although they have no official status, they are clearly influential.

WCRAQ has a working party chair from SupaTrak, which runs vehicle tracking solutions focused on saving fuel in internal combustion engines (ICE). Another chair has a background in reducing diesel and petrol vehicle pollution.

Delgado's other businesses in used car sales

Delgado describes himself as the inventor, founder and CEO of Pollution Solution Holdings, the firm which markets Roadvent.

He set up his first company, Warranty Clear, for the "maintenance and repair of motor vehicles" and financing in 2016. Since then, he has been director of 10 other businesses.

In most cases, he has been the sole founder and director; most of his companies have been dissolved.

His dissolved companies include We Buy Cars Today, EMC online (standing for exchange my car) and Clear Air Road Cars.

He is still running Exchange My Car and Car History Check, which he started in 2024.

When Salamander tried to contact Pollution Solutions, one number was unobtainable, while the alternative mobile number went through to Exchange My Car.

A "licence to pollute"

The Greater London Authority (GLA) has objectives to reduce road traffic by 27% by 2030 and to increase active travel, these have also been adopted by Lewisham council.

This "modal shift" would have many benefits for residents such as reducing road accidents, improving air quality, reducing climate emissions and improving health.

But Roadvent works counter to the council's mission to clean up the sources of air pollution, instead offering drivers a "licence to pollute".

Attempting to remove air pollution from an open space is highly inefficient and costly, and there are better ways to reduce air pollution in schools and nurseries.

Lewisham's roads should not be used as a test site for commercial gain. And if the council decides to take that risk, it should be paid for doing so.

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