Skip to content

Seven air quality reasons not to expand Heathrow

Anyone who keeps up with the Heathrow third runway debate will know the expansion question is still on the table. The public consultation on the Airports National Policy Statement (NPS), which paves the way for a third runway, first opened in February and closed in May this year. A parliamentary vote on Heathrow’s expansion was due to take place in the latter part of 2017, but has been pushed back by June’s snap election.

Fast forward to October, and the Government has reopened the consultation to the public, having revised its evidence in light of revised passenger forecasts and new modelling on air quality. This leaves us with 44 documents, 2552 pages and four data files to read before it closes on 19th December. The Transport Committee, meanwhile, traditionally strongly in favour of expansion, has been reappointed to provide the official parliamentary scrutiny of the NPS, and has issued a call for evidence in light of the new Department for Transport (DfT) documents, which closes at the end of this month.

National Policy Statements are designed, in part, to stop future governments from overturning decisions on controversial, large-scale infrastructure projects and to speed up the planning process. The decision to expand Heathrow, if it is voted through parliament and survives legal challenge, will be very hard for future governments to block. But despite the fresh evidence, significant uncertainties related to the environmental impacts of Heathrow’s expansion remain. MPs shouldn’t, we argue, take such a big risk; now is not the time to make an irreversible decision that threatens public health.

One of the key questions is whether Heathrow expansion is compatible with achieving air pollution limits and targets. The NPS, in our view, presents an unconvincing case for effective mitigation. Below are seven reasons why air quality presents a barrier to approval:

1. The common sense argument

Air pollution in London, generally, and specifically in the Heathrow area is already at levels that have led to regular breaches, and it goes without saying that this will be made worse by a third runway, which would add an extra 260,000 flights a year and double Heathrow’s air freight. Now is not the time to add to the burden, particularly as the hoped-for improvements in air quality that the Government predicted last time Heathrow expansion was on the table have failed to materialise.

2. A high risk of legal breaches for NO2

The Government argues that effective implementation of the Air Quality Plan (which remains subject to legal challenge) will allow Heathrow to expand by the mid-2020s without breaching legal limits. But the new analysis published for consultation shows that the margin between pass and fail is slim, and there is a high risk that expansion will cause legal breaches. The new aviation demand forecasts predict that a third runway will fill up more quickly than originally expected, with the new runway expected to be almost full by 2030. This will lead to a greater impact on air quality in the first few years of the runway being in use.

3. Impacts of construction

Despite acknowledging that the construction of the third runway will have a significant impact on quality of life, the NPS does not model the impacts of construction on legal air quality limits.

4. Future breaches of the National Emissions Ceiling Directive (NECD)

The NECD set limits for the amount of pollutants actually produced, as opposed to the concentration of N02 in the atmosphere. While we currently comply with the Directive, by 2020 we are due to be in breach of the limit for small particles (PM2.5), and Heathrow expansion is predicted to worsen this breach.

5. Whether or not Heathrow expansion causes legal breaches depends on an air quality plan described as ‘weak and incoherent’

Creating headroom for Heathrow expansion while achieving legal limits depends on effective implementation of the Air Quality Plan, which aims to tackle roadside NO2. But environmental law firm ClientEarth has branded the plan ‘weak and incoherent’, and recently announced that it will be taking the Government to court for the third time over failure to deliver air quality improvements quickly enough. It is hard, in this context, to feel confident in the Government’s ability to tackle the air quality crisis. In an unfortunate twist of fate, meanwhile, the plan puts almost all responsibility for tackling air pollution onto local authorities, including those who are opposed to Heathrow expansion on air quality grounds but who don’t have the authority to stop it.

6. There’s no Plan B if the forecasts are over-optimistic

The NPS makes Heathrow responsible for demonstrating that the construction and operation of a third runway will not affect the UK’s ability to comply with legal obligations, and says that it must “strive to meet its public pledge to have landside airport-related traffic no greater than today”. But there is currently no meaningful provision for enforcement if Heathrow’s modelling turns out to be wrong, or if it fails to meet its surface access pledge.

7. Even if the UK does pass the legal test, a third runway will still cause harm to health

Even if the UK manages to get nitrogen dioxide and particulate emissions to within legal limits, air pollution, even at lower levels, can still harm health, and this will be exacerbated by Heathrow expansion. It is becoming increasingly clear that air pollution standards are not tough enough. Whilst much of the focus has been on NO2, it is important that we do not overlook the impact of other pollutants; the Guardian recently revealed that “every Londoner is breathing dangerous levels of toxic particles”, and whilst we do have limits for particulate matter concentrations, they’re some way above those recommended by WHO.

We will be developing these arguments for the Transport Committee, and they will also form part of our response to the DfT’s consultation which closes in December.