Chairman of Commons Environmental Audit Committee says Cameron must answer questions on Heathrow expansion

The House of Commons Environmental Audit Committee recently set up an Inquiry on the “Airports Commission report: Carbon emissions, air quality and noise.” It closed on 3rd September. A considerable number of submissions have been made, from councils, organisations, individuals (and a few from the aviation industry or its consultants). The Chairman of the Committee, Hugh Irranca-Davies, has said that the Government has “big questions to answer” over how it could meet the legally binding EU air quality rules while backing a 3rd Heathrow runway. The submissions, including the one from Transport for London (Boris Johnson) raised a series of objections to a bigger Heathrow. Boris said: “The Commission has failed to demonstrate that a three-runway Heathrow, even with mitigation, will not have the worst NO2 concentration in Greater London, so risking the compliance of the entire zone and EU fines on the UK.” He said the Commission failed to recognise the impact of increased road traffic. Clean Air in London said: “If the Commission is suggesting that the only relevant requirement is that additional runway capacity should not delay in time average compliance throughout the London zone, then it has misdirected itself on the law.”  Sections on air quality from a number of submissions are copied below.


The  whole list of submissions can be seen here. 

David Cameron must answer questions over Heathrow expansion, says MPs’ committee chief

22.9.2015 (Standard)

David Cameron was today warned that the Government has “big questions to answer” over how it could meet EU air quality rules while backing a third runway at Heathrow.

London Mayor Boris Johnson, environmentalists and campaigners raised a series of objections to a bigger Heathrow in a dossier of evidence presented to the Commons environmental audit committee.

EAC chairman Huw Irranca-Davies said: “This evidence shows that the Government still has big questions to answer about how it would achieve the UK’s legally binding commitment to limit air pollution if it accepts the Airports Commission’s recommendation for a new runway at Heathrow.”

City Hall’s submission is scathing about the conclusions of the Airports Commission over how Heathrow could expand while not delaying UK compliance with EU air quality regulations. The Mayor said: “The Commission has failed to demonstrate that a three-runway Heathrow, even with mitigation, will not have the worst NO2 concentration in Greater London, so risking the compliance of the entire zone and EU fines on the UK.”

Campaign group Clean Air in London said: “If the Commission is suggesting that the only relevant requirement is that additional runway capacity should not delay in time average compliance throughout the London zone, then it has misdirected itself on the law.”

Mr Johnson said the Commission failed to recognise the impact of increased road traffic. Airport chiefs, though, said that the greatest contribution to local air pollution comes from non-airport-related road traffic.



Thank you Christine for sending the SHE response.
Click on …Written Evidence. ..View All.



The section on Air Pollution, from the response from West London Friends of the Earth:  Link 

Air pollution

The air pollution assessment by the Commission is extremely suspect.  The Commission used a new model which suggests that the legally binding UK and EU air pollution Limit Values would not be breached by 2030, and air pollution would therefore not be an impediment to a new runway at Heathrow.

Firstly, it should be noted that the new model predicts that air pollution from sources other than Heathrow will plummet between now and 2030.  This reduction, with its welcome potential to improve public health, can therefore be appropriated by allowing extra pollution from a third runway.

Secondly, it should be noted that the older, more established, model paints a far less optimistic forecast of pollution levels.

Thirdly, the air pollution estimates are for 2030, when the runway will only be about 5 years old and will only be partly used.  The real impact of a runway – a fully used runway – is hidden.

Fourthly, achievement does not mean that there will be no health impacts from air pollution. Extensive research, including a very recent report ( ) shows clearly that there are morbidity and mortality effect of air pollution of PM10 and PM2.5 at levels well below the current EU limits.  Friends of the Earth believes that the aviation industry has a responsibility to protect human health, not just to avoid legal action from the EU.

Finally, “the Commission recommended that new capacity at Heathrow should not be released unless doing so would not delay compliance with European law ..” This is nothing short of confidence trick by the commission.  The UK will not achieve compliance with European law until all locations in the UK meet limit values.  There are a handful of sites in central London that have higher levels even than those at Heathrow. So as long as air pollution levels around Heathrow remain are lower than the worst hotspot in central London, there is no constraint on Heathrow’s air pollution.  The EAC should not be conned.

Instead of allowing its recommendation for a new runway to be influenced by air pollution considerations, the commission has simply come up with some policies which might be considered to offset the extra air pollution from a third runway. There is no evidence that the policies are realistic and the commission does not recommend anything.



The section on Air Pollution from the response from the AEF (Aviation Environment Federation):  Link 

Air quality impacts

Government policy

  1. As in the case of climate change, the Government’s approach on air quality is bound by delivery of legal duties. The Air Quality Standards Regulations 2010 transposed into UK law the requirements of the European 2008 air quality directive (Directive 2008/50/EC), which sets legally binding limits for concentrations of major air pollutants that impact public health. While the UK is currently compliant with some of these limits, it remains persistently in breach of the requirement that annual mean NO2 may not exceed 40μg/m3, with sites along major roads both in central London and in the Heathrow area recording breaches every year. The UK is required to meet these limits ‘in the shortest time possible’. In April this year, the UK Supreme Court ruled on a case brought against the UK Government by legal campaign group Client Earth, that the Government’s current policy plan to meet legal air quality limits that came into force in 2010 by 2030 was inadequate and that new policy must be drawn up by the end of this year.
  2. The Airports Commission quotes the National Planning Policy Framework as indicative of Government policy on air pollution, namely that: “Planning policies should sustain compliance with and contribute towards EU limit values or national objectives for pollutants, taking into account the presence of Air Quality Management Areas and the cumulative impacts on air quality from individual sites in local areas.”
  3. Nevertheless, the Commission developed its own ‘test’ against which, it argues, the air quality impacts of expansion should be considered. This is not that the UK must be compliant with EU air quality regulations by the time the runway is built (as was the case in 2009 when the Government announced the environmental limits accompanying its support for a third runway with the Environment Agency proposed to assess compliance).Instead, the Commission proposes that “New capacity should only be released when it is clear that air quality at sites around the airport will not delay compliance with EU limits.” The Commission’s proposed objective does not require that the limits are met but only that the Heathrow area should not be responsible for the most serious breach. In particular, the Commission argues that if, by 2030, there is anywhere in London where air quality is worse than at Heathrow then the airport cannot be held responsible for delaying compliance with the legislation. The Commission appears to pin its hopes on sites on the Marylebone Road continuing to record exceptionally bad air quality.
  4. We do not consider this a sound test of the airport’s sustainability and note that Alan Andrews of Client Earth, the successful litigant in the court case mentioned above, has argued that “If the Government makes a decision based on this test, it would be vulnerable to legal challenge.”[5] Even if the Commission’s proposed mitigations to deliver its air quality objective were realistic and achievable, therefore, we do not believe that they would deliver sufficient improvement to meet the legal requirement reflected in Government policy.
  5. The Commission had earlier set itself an appraisal objective for its shortlisted scheme ‘To improve air quality consistent with EU standards and local planning policy requirements.’ None of the schemes however passed this test with the appraisal concluding that a new runway at Heathrow would have an ‘adverse’ to ‘significantly adverse’ impact on air quality. The scheme would worsen air quality (in terms of annual mean NO2concentrations) at about 47,000 properties, the Commission estimates.


Mitigations proposed by the Airports Commission

  1. The Commission does not set out a clearly defined policy package to be delivered either by the Government or the airport in order to bring air pollution even to the level required by its own proposed test, let alone to within legal limits, and does not set out by whom mitigation should be enforced. But ensuring that the Heathrow area does not, following expansion, record NO2 levels that are even higher than those on the Marylebone Road will require effective mitigation, the Commission states, such that “Local and national Government will need to work together with the scheme promoter to develop a robust set of mitigations to manage both background and airport demand.”[6] The Commission’s analysis includes a number of potential actions, therefore, described as sensitivities, that may result in air quality slightly better than in the baseline forecast.

Are the indicative policies and proposed mitigations set out in the Airports Commission’s recommended option realistic and achievable?

  1. While we do not in this response provide detailed comment on the feasibility of individual mitigations proposed, we note that the Commission’s own analysis raises questions about the deliverability of the measures it suggests.


What are the implications of adopting or not adopting those policies and mitigations for wider Government policy?

  1. Should the possible improvements associated with measures considered by the Commission fail to materialise, the Commission’s modelling suggests that the Heathrow area could, with expansion, have the worst air quality in London. But even if all the mitigations were successful, our understanding is that the Commission’s prediction is that the Heathrow area would continue to significantly breach the EU legal limit for NO2 of itsannual mean not exceeding 40 µg/m3. The mitigation options, the Commission says, could collectively reduce NO2 by 2.4 to 3.6 µg/m3. But the unmitigated forecast is as high as 48.7 µg/m3 (or 47.4 without expansion).[7]


Do realistic and achievable alternatives to those policies and mitigations exist, should the Government adopt the recommended option?

  1. Our view is that a Heathrow runway should not be sanctioned until the area is compliant with legal standards for air quality. We have yet to see a mitigation plan that can deliver this objective through realistic and achievable means.



Response from Clean Air in London:  Link 

  1. I am writing on behalf of Clean Air in London (CAL) to respond to the Environmental Audit Committee’s (EAC’s) inquiry into the Airports Commission’s report (the Inquiry).
  1. CAL is a voluntary organisation which campaigns to achieve urgently and sustainably full compliance with World Health Organisation (WHO) guidelines for air quality throughout London and elsewhere.  Further information about CAL can be found at
  1. CAL is independent of any government funding, has cross party support and a large number of supporters, both individuals and organisations.  CAL provides a channel for both public concern and expert opinion on air pollution.  This document provides both general and expert comments in response to the Inquiry.
  1. Airport related traffic is a major cause of air pollution in London, which in turn causes thousands of premature deaths per year, and many thousands more illnesses, chronic illnesses and disabilities.  For this reason, airport expansion impacts on air pollution.
  1. The Davies Commission into London airport capacity makes some ambiguous remarks about the relevance of Directive 2008/50/EC on ambient air quality and cleaner air for Europe (the Directive).  CAL makes two points.
  1. First, if the Davies Commission is suggesting that the only relevant requirement is that additional runway capacity should not delay in time average compliance throughout the London zone, then it has misdirected itself on the law.  For example:


  1. the limit values must be met throughout each zone (save in three specifically excepted circumstances defined in Annex III(A)(2) of the Directive).


  1. air quality must not be made even less compliant in areas where it is already in breach.


  1. Second, any suggestion that the additional capacity could be constructed but on the basis that it would not be brought into operation until air quality was, and would remain, compliant with the Directive would, in present circumstances, be inconsistent with the duty of restraint in the last part of the Treaty on European Union (TEU) Article 4 (3).


The TEU can be seen here:

Unless a robust, realisable and enforceable air quality plan is in place which can demonstrably ensure compliance after the additional capacity comes into operation then the duty of cooperation under TEU Article 4 (3) requires the UK to refrain from constructing such additional capacity.

  1. CAL made similar points to the Airports Commission in a letter dated 23 May 2015 responding to its consultation on new evidence relating to an air quality assessment of the three short-listed options for additional airport capacity.  Our response to the Airports Commission can be seen here:

  1. CAL is seeking an authoritative legal opinion on this matter and will share it with the EAC when available.
  1. In CAL’s considered opinion any decision to approve airport expansion at Heathrow would breach air quality laws unless at a minimum there is an existing robust, realisable and enforceable plan in place to ban diesel vehicles for many miles around the airport, including the M4 and M25 motorways, before the additional capacity comes into operation.



The section on Air Quality from the submission by the 2M group of councils,  Hillingdon, Richmond, Wandsworth and Windsor and Maidenhead :  Link 


B              AIR QUALITY

1              Major shift in mode share for those working and arriving at the airport, consideration of a congestion or access charge.

Question 1 – whether the proposed mitigations are realistic and achievable.

3.1              We do not believe the Commission has demonstrated sufficient confidence that these proposed measures are deliverable. These have been identified as possible air quality mitigation measures, which means that any risk of non-delivery or lack of control on implementation, will have negative implications for ensuring air pollution levels are met.

3.2              The shift to public transport to date at Heathrow has been much slower than that which the Commission assumes will take place with expansion. The Heathrow Sustainable Transport Plan 2014-2019 (page 18/19) details a trend in mode share from 32.5% in 1998 to 40.6% in 2012, which is an increase in 8.1% over 14 years. A further step change is not anticipated until 2024, when schemes such as Crossrail, Western Rail Access and improvements to the Piccadilly Line upgrade come into force and a modal share of over 45% could be expected.

3.3              The Heathrow Air Quality Strategy 2011-2020 defines airside ground movements and staff travel to the airport as something they can ‘guide’ and the aircraft fleet mix andpassenger traffic as something they can ‘influence’. None of these are within the control of Heathrow.

3.4              The major scheme identified by the Commission as achieving a further step change with expansion is a southern rail access link. We believe a suitable additional link is required to address today’s problems with access to the current airport. This should be addressed and paid for by the airport now.  Adding it to the new package of taxpayer funded transportupgrades to deal with an expanded airport is completely inappropriate. There is currently no firm proposal or funding stream for this additional rail provision which also suggests a potential risk in delivery. No details have been provided of any evaluation of a congestion or access charge; the traffic reduction it would achieve; or on the public acceptability of such a charge. Thisagain suggests a potential risk in delivery.

3.5              There is an increasing amount of evidence in relation to the detrimental health impacts of air pollution. It is not safe, in terms of policy decisions, to assume that the current health limits will not be tightened in the future. The mitigation measures would need to be sufficient to achieve a level below that of the current limit value to ensure there is a) sufficient headroom to account for the need to maintain compliance, and, b) to future-proof the use of the new runway should health evidence suggest a lowering of the standard.  Without this, the likelihood is that it will result in new airport infrastructure being built but the additional capacity not released for use.

Question 2 – the implications of adopting or not adopting those mitigations for wider government policy.

3.6              Airports are large attractors of surface access journeys. Around Heathrow, airport-related traffic contributes to air pollution levels which are above European limits. Targets for mode share and any congestion charge zone must be set at a level which ensures a reduction in pollution from this source. To not achieve a reduction in pollution will compromise compliance with European air quality legislation and harm the health of local communities.

Question 3 – whether realistic and achievable alternatives to those mitigations exist.

3.7              The mitigation measure must ensure air quality compliance is achieved under current operations. Once compliance has been reached, measures must be implemented to ensure that there is sufficient control to maintain compliance under the two runway airport before any expansion is decided upon.

3.8              There must be proper evaluation of the proposed and any alternative mitigation measures to ensure reductions in traffic are achievable.  There would need to be additional traffic management measures in place to ensure that reductions in airport related traffic are not simply taken up by other non airport road users. The revenue from the congestion charge must be ring fenced for local community improvements.

2              New capacity only released when it is clear sites around the airport will not delay compliance with EU limits

Question 1 – whether the proposed mitigations are realistic and achievable.

3.9              We believe the Commission’s approach in relation to compliance with EU limits is incorrect and potentially unlawful. It seems to suggest that the only obligation on the UK is to produce air quality plans to achieve compliance and that operations at Heathrow will be a legal problem if, and only if, they are responsible for a delay in complying with EU limit values.  This misunderstanding of the law leads to their interpretation that there is no need to worry about Heathrow if there is somewhere else in the zone which is worse.

3.10              The Commission recognises that there is a risk of failing to meet the air quality limits, even on their own interpretation of the law, and has sought to cover this by setting a condition which states additional capacity can only be released when it is clear there will not be a delay in compliance with air quality limits. There is no detail as to how this condition will bemonitored and enforced in practice or who the regulator and decision maker would be with regards to the release of capacity.  There has been no consideration of the economic dis-benefits arising from such vast and costly infrastructure being built but not able to be fully utilised. We believe that there is insufficient evidence to suggest this mitigation measure could be either realistic or achievable in practice.

Question 2 – the implications of adopting or not adopting those mitigations for wider government policy.

3.11              The principle of being required to meet EU limit values should be implemented now on the current airport operations, not just related to an expansion scenario. The safe limit to protect health was meant to be achieved in 2010; the Government now predict this will not occur until after 2030; and expansion at Heathrow makes this situation considerably worse.  Failure to achieve EU limit values would be to fall foul of European air quality legislation (the Air Quality Directive) and potentially risk the imposition of fines to the UK Government for non compliance. It also fails national planning legislation such as the National Planning Policy Framework (NPPF, para 124) and the APF (para 3.47) which both reiterate the Government’s commitments to meet EU limit values. The additional burden on the health of the local communities also needs to be properly costed and taken into account.

Question 3 – whether realistic and achievable alternatives to those mitigations exist.

3.12              It is our view that if realistic and achievable mitigations measures were available, they should have already been implemented.

Question 4 what steps should the government take to reach a decision that is consistent with its commitments on sustainable development.

3.13              In our opinion the current Heathrow operation is unsustainable. The T5 Inquiry attempted to set controls to constrain the environmental damage caused by the operation of the airport within a densely populated area.  Unfortunately the Commission has failed to explain why it believes these can now be disregarded.

3.14              The expansion of Heathrow fails the NPPF policy of ensuring that development is appropriate for its location. The surrounding area, of which Heathrow is a significant contributor in terms of pollution emissions, currently fails air quality limits; it has been demonstrated that it will do so until 2030; and expansion will make this situation worse.

3.15              In our opinion the proposed mitigation measures will not address the harmful implications on health arising from air pollution, and therefore the recommendation to expand Heathrow does not represent sustainable development.

3.16              We note that the Commission’s Final Report made it clear that its mitigation measures are an integral part of the recommendation for Heathrow expansion.  Given that the air quality mitigation measures are not realistic and achievable, it follows, on the Commission’s own reasoning, if the measures are not adopted, then the recommendation to expand Heathrow must be rejected.  Notwithstanding this, we believe that even if all the conditions proposed by the Commission were workable, that the Government should not allow the proposal because it is unsustainable.




Section on Air Quality from the submission by Transport for London (TfL) – the Mayor of London  Link

  1. Air quality

3.1.             The additional road traffic demand from the recommended proposal is significantly under-estimated.

TfL estimates that the incremental road traffic demand from the recommended proposal could be of the order of tens of thousands of additional vehicle movements per day. By any measure this is a very significant degree of under-estimation and it is of course over and above that already taken into account in the Commission’s air quality assessment, which takes only a ‘bare minimum’ approach to mitigation.

The additional demand at sensitive locations, such as the Bath Road which, according to Defra, currently has the second-worst air quality in Greater London, would certainly be a major additional impediment to achieving air quality limit values at any point in the future. This would lead to increased NO2 concentrations over and above that projected to be achieved (with mitigation) by the Commission under the recommended proposal. This would result in a much more demanding level of mitigation than envisaged by the Commission. It is crucial that realistic demand figures and the proposed revised alignment of Bath Road are tested via modelling for air quality impacts, with assured mitigation, ahead of any decision, rather than simply assuming that the problem will either go away or become a fait accompli (only to be discovered) when the new capacity comes into operation.

This level of additional demand would either need to be accommodated in practical terms, for example through further enhancements to the transport network (which is acknowledged by the Commission to be operating at over-capacity) or, there would be significant additional air quality impacts on the local highway network on a much wider scale and over more hours. The effects would require comprehensive mitigation which has not been identified by the Commission and which undermine the economic viability and feasibility of the project.

3.2.            The Commission adopts a ‘bare minimum’ approach to meeting air quality objectives, which is inadequate, and does not meet its own appraisal objectives.

Air quality is universally acknowledged as a key public health issue both at national and EU level and this is why it is the subject of legally binding limit values designed to minimise the threat to public health over the shortest possible timescale. The UK is currently projected to be in long-term breach of the limit value for Nitrogen Dioxide (NO2) until post-2030 (although this expectation may change over the short term in the shape of the Government’s response to the recent Supreme Court judgment in Client Earth). The Greater London zone, in which Heathrow largely falls, is projected to be the last in the country to comply. The focus of local and national policy is on how compliance with these limits can be brought forward to the earliest possible date. From first principles, therefore, any expansion of Heathrow would militate heavily against these imperatives and would require substantial mitigation even to get back to a position of ‘standing still’ (i.e. the Do-Minimum situation) – let alone actually working to improve air quality. The Commission does not address these requirements.

The Commission’s treatment of air quality is complacent and, in some places, ambiguous. This casts doubt on the veracity of its understanding and the soundness of its assessment. In particular, whilst acknowledging that this is an ‘all or nothing’ test of deliverability for an expanded Heathrow (see, for example, paragraph 9.52), the Commission fails to demonstrate that it will not, in fact, be a significant issue, and that the adverse effects will be satisfactorily dealt with.

The Commission sees air quality as an obstacle that it seeks only to mitigate to the bare minimum required – that is no better than the otherwise expected worst concentration within the zone. This is expected, on the basis of most recent forecasts available to the Commission, to be Marylebone Road. This approach is open to legal challenge for the following reasons. Firstly, the Guidance relied on by the Commission (a Highways England Interim Advice Note, IAN175) itself does not provide a definitive legal basis for establishing compliance with air quality objectives. Secondly, the Commission then fails to adhere to the principles of the Guidance, which require that in the event of a scheme making air quality worse when it is already above the limit values (as is the case for Heathrow), that mitigation measures must be identified to reduce air quality concentrations so they either meet (1) the limit values or (2) the same air quality levels without the scheme in place (i.e. the Do-Minimum case), whichever is the higher. In this case, where latest-available projections suggest zonal non-compliance for London, the latter is the appropriate minimum target for mitigation.Thirdly, none of the additional tests set out in the Guidance have been undertaken, including disclosure of whether there is an overall increase, decrease, or no change in NO2 concentrations.

The Commission has done none of these and, in so doing, has accepted a widespread worsening of air quality (with no offsetting positive impacts), gives itself no room for manoeuvre and, notably,fails to address its own appraisal objective ‘to improve air quality’ (see paragraph 9.92). Furthermore, the benchmark comparison against Marylebone Road is now already out of date, as TfL’s Ultra Low Emission Zone scheme (now a committed scheme) will have the effect of significantly lowering emissions here from 2020. At that point, in the absence of further change, the A4 Bath Road would likely be the ‘worst link’ in the Greater London zone.

Given the importance of this issue, greater ambition and more certainty is required. To be in conformity with wider air quality policy the Commission should at least have demonstrated a proposed package that would ensure no overall worsening/increase in NO2 concentrations across the affected study area, from the ‘Do-Minimum’ rather than solely the ‘next worst road link’ approach actually adopted.

A logical corollary of the ‘next worst link’ approach adopted by the Commission would be that air quality could get worse across the Greater London zone provided that it did not get any worse than Marylebone Road. This is clearly nonsense in public health terms, and is against the principles required by the EU Directive that require Governments and other responsible authorities to work towards achieving compliance with limit values at the earliest possible date.

Such assurance should also have been given for all stages of the construction and operation of the expansion – at the start of operations, when background concentrations would be at their highest, and at several incremental stages of operation, when emissions arising from the expanded airport would be at their highest. The extent of the information given, as well as the level of assurance about progress towards meeting limit values, is therefore inadequate.

The Commission seems ambivalent or oblivious to the fact that, as demonstrated by its assessment, Heathrow currently is, and will continue to be, a significant source of air quality problems that are inhibiting compliance with air quality objectives in the Greater London zone. The fact (even if correct) that there may be other significant sources which are possibly worse is an entirely unconvincing excuse in scientific or legal terms and is most unlikely to persuade the European Commission, a UK judge or the European Court of Justice.

3.3.             The adequacy and deliverability of mitigating measures is not convincing.

Even on the basis of the Commission’s estimated scale of air quality impact, which has been significantly under-estimated, and its limited ambition to reduce this, the adequacy and the deliverability of the mitigating measures as set out is not convincing. They are poorly-specified and quantified, are not committed to in any meaningful form, and presuppose actions from third parties which have not been verified. We therefore doubt that, even in its minimal form, it is credibly deliverable, and observe that it ties any decision on Heathrow expansion to a range of imponderables that may – or may not – be considered to happen, depending on the agenda of the commentator.

Mitigation is seen as a limitless ‘catch all’ that can solve whatever air quality problems arise. Undoubtedly it can if it is extensive or draconian enough – but that is not the point. Higher impacts and/or higher levels of ambition would require correspondingly greater mitigation, which may have to be of such a scale as to be ‘transformational’ – for example requiring significant new public transport capacity at additional cost and/or being such as to inhibit the realisation of the very economic benefits sought by the proposals, for example a powerfully discouraging road user charging scheme which would require a wide ranging expansion of public transport provision in its own right. All of this suggests that the costs of the third runway have been substantially under-estimated, and that the business case is consequently flawed. Standing back, which sensible business would proceed with a project the ultimate use and cost of which would be dependent on such uncertainties, or be willing to assume that all such matters will be resolved satisfactorily? Yet this is exactly the basis upon which the Commission has assumed that the scheme proceeds.

The Commission’s reluctance to consider or assess mitigations of this scale is telling. This is a reflection of its complacent stance on this issue, and it does not have due regard to the actual infeasibility and/or extremely high cost of mitigation that would be required to provide a more acceptable level of assurance on air quality. For any decision to be properly grounded, these requirements must befully addressed and their efficacy conclusively demonstrated. Statements like “air quality impacts should be addressed wherever possible” are further evidence of the Commission’s half-hearted approach to this issue and its incomplete understanding of its importance.

The Mayor’s position is therefore that the proposals should properly have included a committed, fully-costed and deliverable package of mitigation that assures, as a minimum, no overall deterioration in air quality in the affected area, maintains this state from that point onwards, works towards achievement of limit values at the earliest possible opportunity, and does not significantly damage the ‘business case’ and economic benefits sought by the expansion. In the absence of such a costed package, no sensible investment decision can be made.

3.4.            Any Government decision on the proposals need to be fully cognisant of, and aligned with, the UK’s response to the Supreme Court ruling, and the soon-to-be-published (for consultation)revised NO2 Action Plan. It is not possible to see how this can be achieved over the short or medium term.

The positioning of the Government’s decision on the Commission’s recommendations given the parallel requirement to respond to the Supreme Court, via a NO2 Action Plan, is of crucial importance, as this will effectively reset the baseline against which the air quality impacts should be judged, probably bringing forward the expected date of compliance within the London ‘zone’ (this is an explicit requirement of the Supreme Court ruling). This could fundamentally affect the applicable target for air quality mitigation, depending on any change to the future projected compliance status of the Greater London zone.

The timeline of the adoption of the Action Plan is also likely to be lengthy – this being subject to consultation, possible legal challenge and formal adoption by the European Union. This means that the final shape and details of future air quality compliance will not be definitively known for maybe two years or more.

The Commission’s own response to these issues was that it ‘considers that expansion at Heathrow should be capable of being incorporated into that plan without delaying compliance…’. At best, this is a massive hostage to fortune. At worst, it is a reflection of gross complacency and ‘throwing the problem over the fence’ (see paragraphs 14.112 – 14.114). In the Mayor’s view, this could not possibly be achieved when the Commission’s assessment makes no attempt to show how either the do minimum or limit values could be met because the mitigation package provided does not aim in any way to meet limit values – a fundamental requirement of the Action Plan. A very major new source of air pollution in an area which is non-compliant and which must become compliant within demanding timescales is a problem which cannot be dismissed so easily as the Commission appears to do.

Bearing in mind that an expanded Heathrow will almost certainly not be considered in the Action Plan, there are several possible outcomes. If the anticipated date of compliance in the Greater London zone is ahead of a new runway coming into operation, then by definition the air quality impacts of the expansion cannot be allowed to reverse that position. Such an outcome would require a comprehensive reassessment of the air quality impacts so as to not prejudice compliance with limit values at the earliest date projected by the Action Plan.The requirements would, by definition, be very demanding indeed. It would not be possible to extrapolate from the current assessment as the context and assumptions would have fundamentally changed. The level of assurance required would also be much more stringent, as the UK’s compliance status would be dependent on the outcome. Furthermore, this level of assurance would need to be given at all stages of the construction andoperational development of the new runway.

Should the expected date of compliance set out in the Action Plan correspond with the early stages of the bringing into use of the new capacity, then the incremental impacts of expansion would assume critical importance, as they would be acting in the opposite direction to all other factors affecting air quality at this time. Yet again, a completely revised assessment and very high levels of mitigation and assurance are called for.

Whatever the actual revised projected date of compliance, if it is the Government’s view that the Heathrow proposals must simply ‘fall into line’ with the trajectory to compliance set out in the ActionPlan, the requirement for mitigation and assurance, would be greater, possibly very much greater, than that assumed by the Commission. In all cases, the requirement must be for a completely revised assessment with very high levels of mitigation and assurance. This would imply difficult practical issues connected with the provision of surface access and significant additional costs, which have not been fully accounted for in the proposals and which should not properly fall on the public purse.

Whilst it cannot at this stage be known for certain, it is very likely that the Government’s Action Plan will significantly ‘raise the bar’ for the assessment and mitigation of air quality impacts. It surely will have to if it is to have any chance of being accepted by the European Commission and not leading to further proceedings in the domestic or European courts.  An expanded Heathrow will thereforeneed to comply with more stringent air quality requirements, to a tighter timescale, with a more stringent level of assurance, and at greater cost, than foreseen by the Commission. All this is on top, of course, of the generic under-estimation of the scale of impacts that TfL believe has taken place in the Commission’s assessment.

TfL have previously responded[7] to the Commission’s final consultation raising a number of concerns in relation to the technical methodology employed when undertaking the air quality modelling which concluded that the air quality impacts and necessary levels of mitigation had been underestimated.

It should therefore be recognised from the outset that a decision to expand Heathrow Airport based on the information to hand is not technically feasible and will potentially draw the Action Plan into disrepute. It is therefore inconceivable that the Government could be in a position to have sufficient information to make a reasonable and proper determination on the basis of air quality impacts at this point.

Further work required

  • Revision and updating of the partial approach to traffic demand estimation provided by the Commission to date is required, and a re-working of the air quality impacts assessment on this basis is also required (for further comment, see Surface Access section).
  • The Government should produce a ‘road map’ detailing how impacts constrained to the ‘do minimum’ case would be achieved, and how the proposals work towards compliance with air quality limit valuesat the earliest possible date.
  • Mitigation should be presented with the (at least minimum) aim of delivering air quality representative of the situation without the expansion, in the case that the London zone is still forecast to be non-compliant in Defra’s most recent assessment rather than just seeking to mitigate to the ‘next least worst’ (and higher concentration) road link within the London zone.
  • Should the Government’s NO2 Action Plan project zonal compliance for Greater London by the time of opening of an expanded Heathrow, then the Government should provide a robust and costed assessment that demonstrates that limit values will not be infringed at any stage.
  • The Government’s decision on the proposals must consider the parallel requirement to respond to the Supreme Court’s order by an NO2 Action Plan. Sufficient information needs to be available for the Government to make a proper determination on the basis of air quality impacts. This is unlikely to be possible for up to two years.



The section on air quality from Hounslow Borough Council.  Link

2.0              QUESTION 1

Whether the indicative policies and proposed mitigations set out in the Airports Commission’s recommended option are realistic and achievable


2.1              Local air quality is extremely important to us but is now also an issue of national significance.  As a result of a Supreme Court decision, the UK Government must by the end of 2015 submit an action plan detailing how it will meet the standards for Nitrogen Dioxide.  This will create a supervised process for regional and national measures required to resolve the background air quality issue.

2.2              Nitrogen Dioxide (NOx) concentrations within the Heathrow area are higher than the permitted EU limit and have been for a considerable length of time.  The London Borough of Hounslow has been designated as an Air Quality Management Area (AQMA) due to exceedances in Nitrogen Dioxide.

2.3              The Council accepts that there is a balance to be struck between the vibrancy of the economy and the environmental effect of the airport operation whether expanded or not.  In a recent community survey undertaken by Hounslow Council, 70% or respondents said that they were concerned about poor air quality and high levels of pollution in the Borough.  Continuing poor air quality without the prospect of improvement after 20 years of policy implementation is not acceptable.

2.4              Hounslow Council believe that any future expansion at Heathrow Airport that does not meet the EU limit value objective for Nitrogen Dioxide or pushes a compliant area back above the limit could be deemed unlawful. In any case, this would be unacceptable in a civilised society. Were the present levels of air pollution in our Borough to be visible in the same way as twentieth century smog, action would have been taken far earlier. This pollution is no less harmful to our citizens.

2.5              We welcome the Commission’s recognition of the need for air quality mitigation measures to be implemented because congestion on our Borough’s road network generated by the presence of Heathrow is a significant issue. It gives rise to poor air quality, affects community health and limits the ability of our local economy to diversity.

2.6              Within their Final Report, the Airports Commission proposed that any new capacity at Heathrow should not be released unless doing so would not delay compliance with European law on air quality. The Commission found that this would require a package of mitigation measures, notably the introduction of a congestion or access charging scheme and measures to encourage surface access by public transport.

2.7              However, we believe that the proposed mitigation measures related to air quality should be implemented before any expansion takes place. Then further measures should be introduced should expansion plans be authorised.


2.8              The proposed third runway is estimated to bring Heathrow’s total capacity up to 740,000 air traffic movements (ATMs) per annum.  The Airports Commission has recommended that slot capacity at an expanded Heathrow should only be released when it is clear that the air quality at sites around the airport will not delay compliance with the EU Air Quality Directive.

2.9              For Hounslow, the crucial point is the definition of “around the airport”.  It would be relatively easy for the owners of the Airport to achieve compliance within or close to their own boundaries by, for example, using electric vehicles for terminal activities or by employing a congestion charging scheme at their perimeter.  But such measures would not of themselves improve air quality in Boroughs such as ours which are affected by petrol and diesel powered road vehicles running to and from the airport as well as by pollution from aircraft overflying us. Indeed, some of the proposed mitigation measures outlined by the promoter such as an alternative congestion charging zone could simply result in an increase in congestion on the road network in our Borough through traffic displacement.

2.10              If a legally binding agreement is placed on the airport operator that capacity will only be released if compliance with the Directive is not delayed, we require a guarantee that the definition of “around the airport” includes our community.

2.11              Past experience of pledges by the owners of Heathrow causes us to question the willingness of governmental agencies to hold them to such a guarantee after committing expenditure to building the runway. We ask the Committee to recommend that the linkage between improved air quality and the release of new capacity must be totally legally binding with meaningful penalties for abuse.

2.12              Mitigation is so important to us because there are potential increases, albeit small, in the present unacceptable levels of NOx, PM10 and PM2.5 emissions due to surface access flowing from the Heathrow third runway proposals.  These will make task of delivering Hounslow Council’s Local Air Quality Management (LAQM) obligations even more difficult as demonstrated by DEFRA’s PCM maps which indicate exceedances of the annual mean limit value for NO2 along A4 (Bath Road & Great West Road), A312 and A316.




The full list of published responses can be seen at



ABTA’s response does not even mention the air quality issue.