Photo: Scott Barbour / Getty Images
Photo: Scott Barbour/Getty Images

With days to go before a rumoured decision on airport expansion the Today programme yesterday opened by reporting that Heathrow could build a third runway without breaking EU air pollution laws.

The news was accompanied by a online piece suggesting “new, independent research seen by the BBC suggests Heathrow airport could build a new runway without breaking European pollution laws.”

The only problem – the study hasn’t been published or peer reviewed. Indeed, nobody even has a copy.

From what we can tell though its headline grabbing conclusion is based not on assumptions about Heathrow but instead on assumptions about the UK government totally changing how we power our vehicles which are, at best, a little on the optimistic side.

There is no published report

That’s right. The research, conducted by Professor Rod Jones, at the University of Cambridge has neither been published nor peer-reviewed. He said it will be, but not for some time.

The BBC has seen the research – in the form of a presentation – but no longer has it, Jones told Energydesk.

The results were likely presented at a public meeting in September but when Energydesk asked to see it, Jones said he did not want to pass it on because of concerns it would be misinterpreted.

Several outlets, including the Telegraph and the Evening Standard, have reported that the study was led by the University of Cambridge, but it has not publicised it – which isn’t surprising because, until it’s published and peer-reviewed, there is no study.

The conclusions are based on assumptions in the Airports Commission

Which is a problem because the basis of the study’s claims are exactly the sort of contentious issue you might want to examine the detail of.

Last year the Airports Commission made a “clear and unanimous” recommendation that a third runway be built at Heathrow.

But there was a number of conditions, including, crucially, that air quality at sites around the airport does not delay compliance with EU limits on the toxic pollutant nitrogen dioxide, which is believed to be the cause of more than 14,000 premature deaths in the UK.

Airport expansion would increase NO2 levels in the area, which are already in breach of legal limits.

However the conclusion drawn from this new research – we think – is that future reductions in emissions unrelated to the airport – largely from traffic – would compensate for the increase from building a new runway.

“There will be more pollution linked to the airport but it will be against a background of reduced pollution from the wider area so the general pollution level will drop, we think, below the critical level that we currently have for health impacts,” Jones told Energydesk

But the new research does not actually assess whether these reductions in non-airport emissions will happen. 

It verifies emissions caused by the airport, by using sensors to measure air pollution around the airport to differentiate emissions from the airport and around it.

Again, without seeing the research it’s not possible to really know, but it appears that the study’s conclusion that background traffic emissions will fall is based on a number of other reports, primarily that carried out by and for the Airports Commission.

The Airports Commission says the following:

“Even if demand growth at the airport is as high as in the modelling it is reasonable to proceed on the basis that suitable mitigating actions are available to reduce the impact of the Heathrow Northwest Runway scheme to a level where other measures employed to tackle the wider air quality problem can be expected to bring the identified exceedances within legally required limits.”

Such reductions would be brought about by “reduced NO2 from other traffic, because of Euro 6 engines and electrification of the traffic fleet,” Jones told the BBC.

Euro 6 emissions

So the accuracy of the mysterious study appears to depend on whether the assumption that emissions will fall is reliable.

Jones told Energydesk that their conclusions incorporated real world emissions, based on findings for the Airport Commission that use a conformity factor of five – they assume vehicles are five times more polluting in the real world than in tests.

Conformity factors are based on EU rules that should tighten up in coming years - so the Commission findings may prove pessimistic – but government findings from this year show that the average Euro 6 diesel car emits more than six times the emission limit for NOx when tested on British roads.

Given the industry’s track record, and the fact that the UK is leaving the EU, it’s anyone’s guess whether or not these reductions actually feed through by the time a runaway is built.

Government plans

Of course all of this does depend on how many diesel, electric and petrol vehicles there are – not just how polluting they are.

Research by IPPR and King’s College London suggests that in order for London to be compliant within a decade, it is likely diesel cars would have to be completely phased out.

This is not impossible, but doesn’t look likely based on the government’s current record. It may also be referenced in the study – who knows. 

What we do know is that the UK is already falling behind on its commitments to transition to electric vehicles, a cross-party group of MPs has reported.

Forecasts by the Department for Transport predict thatby 2020  the take up of ultra-low emission vehicles will stand at less than 5% of the fleet – half the target recommended by government climate advisors.

Cait Hewitt, deputy director of the Aviation Environment Federation, said that the assumption that the government would introduce such plans to an adequate extent is “speculative and optimistic”.

“The government should not back Heathrow expansion based on this report unless it has the policies in place to deliver the optimistic assumptions in electrification of the transport sector and take-up of next generation of diesel vehicles,” she said.

The Airport Commission also cites the government plans to tackle air quality, prompted by a ruling by the Supreme Court.

It says:

“The recent Supreme Court ruling means that the government has been ordered to take action on air quality, producing an action plan by the end of the year in order to bring forward the national and regional measures required to resolve the background air quality issue. It is reasonable to expect that the proposals in that plan would reduce emissions from road vehicles and so further reduce the unmitigated levels set out above.”

Campaigners have challenged whether this plan is supported by realistic policies and lawyers at ClientEarth who brought the case are taking the government back to court in two weeks time because they say it is inadequate.

Hewitt told Energydesk: “Defra’s air quality plan fails to demonstrate convincingly that the UK is taking sufficient action to meet legal limits, consisting almost entirely of a description of measures already in place rather than setting out steps that will accelerate the UK’s compliance with limit values.”

Even if they are adequate, the earliest date these plans will bring about compliance in London is 2025 – the anticipated opening date for the third runway.

All of which leads to a fairly inevitable question.

And did Heathrow help with the study?

Jones stressed to Energydesk that the research is independent and funded by the Natural Environment Research Council.

He has no links to the car industry, he said.

However, the British Airports Authority supported the project by putting the sensors into Heathrow and by providing detailed information on aircraft movements.

It didn’t really make much difference to the outcome though – as the study’s key conclusion wasn’t based on anything you can measure but on a somewhat optimistic assumption about future government policy.