The Airports Commission Report Follow-up: Carbon Emissions, Air Quality and Noise Contents

2Air Quality


6.The issue of air quality in urban areas continues to move up the political agenda in light of the recent High Court ruling on the Government’s 2015 Air Quality Plan and scientific evidence around the effects on human health of exposure to NOx. In this section we refer briefly to our previous interim report as we consider the impacts of recent Air Quality developments, including ClientEarth’s High Court case and updated COPERT emission factors, on the Government’s analysis of the Air Quality impacts of Heathrow expansion; and then set out our conclusions of what the Government must do over the course of the NPS process.

EU Limit Values

7.The Airports Commission based its air quality conclusions on EU Directive 2008/50/EC, which limits values in respect of certain key pollutants—including an annual mean limit value of 40μg/m3 NO2. Our interim report and this report focused on NO2 concentrations because this is where the worst of the UK’s air pollution problem lies. The majority of main roads in London regularly breach legal values for nitrogen dioxide. It took only five days for the annual EU limit to be breached on Brixton Road in 2017.4 A zone is deemed to be in breach of the Directive if any receptors in different parts—links—of the zone exceed the limit values. The Airports Commission found that expansion would not delay compliance with EU limit values. Critics of expansion were concerned that this depended on an interpretation of the Directive which meant air quality could deteriorate, provided it was less bad than the worst recorded results within the zone.5 For most witnesses, including the Airports Commission, it was the contribution of rail and road access to NO2 levels that was the key factor in determining the impact of airport expansion on air quality, rather than the increased number of aeroplanes arriving at and departing the airport.6 Prior to the publication of the Airports Commission’s report, the High Court ruled that the Government needed to produce a new air quality strategy. In our interim report we recommended:

Before the Government makes its decision, it will need to demonstrate that its revised air quality strategy can deliver compliance with legal pollution limits within the timescales agreed in the finalised [revised air quality] plan to be approved by the European Commission. It will also need to show this can be maintained even when the expanded airport is operating at full capacity. Heathrow’s existing air quality strategy should also be revised to meet the new targets. Failing this, Heathrow should not be able to expand.7

8.Since our interim report, the UK has voted to leave the European Union in a referendum. The Government plans to leave the EU before April 2019. Our inquiry into the Future of the Natural Environment after the EU referendum found that around a third of EU environment legislation cannot be easily cut and pasted into UK law, and that the loss of EU governance and enforcement mechanisms risks UK environmental protections being watered down.8 The Government should set out in their response to this report, and in the National Policy Statement, how it will ensure that air quality standards, and the means of enforcing them, will be as good as, or better than, current EU standards after we leave.

Vehicle Emissions Modelling and Future Testing

9.In response to our interim report, the Department for Transport told us it had accepted the recommendation to test the Airport Commission’s analysis against its revised air quality plan, noting that “this work [...] confirmed the [Airports Commission’s] conclusion that a new runway can be delivered without impacting the UK’s compliance with air quality limit values for nitrogen dioxide.”9 The work to which the Department referred was the Air Quality Re-analysis Study which was based on the assumptions of the impact of the 2015 Air Quality Plan and on Pollution Climate Mapping modelling, using the then most up to date COPERT—Computer Programme to Calculate Emissions from Road Transport—emissions factors.10

10.However, in September 2016, after the Government’s in-depth re-analysis had already taken place, the COPERT emissions factors were updated. The update occurred because, as the 2016 re-analysis explained, the previous factors “significantly underestimated” emissions from Euro 6 diesel cars and Euro 5 and Euro 6 cars and light commercial vehicles.11 The Foreword to the re-analysis, therefore, included an “initial qualitative review” of the new evidence and produced two forecasts based on different runway opening dates. It also modelled the impact of new vehicles on the road, which will have to be compliant with stricter real driving emissions tests (RDE), due to be implemented for all new car registrations in 2021.12 The Foreword stated:

In 2025, with RDE fully effective but some older and RDE non-compliant vehicles remaining in the fleet [...] the risks remain that the Heathrow Northwest Runway [...] could impact on EU limit value compliance [...]; [therefore expansion could] cause a worsening of exceedances of the limit value alongside one or more PCM [Pollution Climate Mapping] links without delaying compliance of the zone/agglomeration.

By 2030, assuming that the majority of the fleet is fully RDE compliant and with the influence of non-RDE compliant vehicles reducing over time, it is possible that the projected compliance with EU limit values [...] could be maintained.13

11.Hillingdon, Richmond, Wandsworth and Windsor and Maidenhead local authorities were highly critical of this reanalysis. They said:

We are greatly concerned that the Foreword is not a proper analysis, it is described as a qualitative review. This is an unacceptable approach. The Government should have re-modelled and undertaken a proper assessment using the new emissions factors before coming to any conclusion on the air quality impacts of Heathrow expansion.14

12.During our evidence session the Transport Secretary told us that the detailed data on the impact of RDE had not been available to the Cabinet sub-committee which took the decision to approve Heathrow expansion:

At the time that the sub-committee took the decision, we did not have the full detailed data on the new emissions factors, so we did a qualitative analysis. We are now doing a full model run, which will be incorporated in the appraisal of sustainability that will be published early next year and consulted on.15

13.The Airports National Policy Statement published on 2 February 2017 included the Government’s Updated Air Quality Re-analysis. This was published as a “follow-up” to the previous Re-analysis study, but incorporating the updated COPERT factors. The scope of this study mirrors that of the previous, it re-analyses “existing datasets to assess the implications of the updated COPERT emission factors, and associated updates to the PCM projections, on the conclusions of the AC’s work in relation to EU limit value compliance”.16

14.The conclusions of this study, using the updated vehicle emissions factors, echo those of the Government’s previous re-analysis:

In 2030, the option [Heathrow Northwest Runway] does not impact on compliance with limit values in the core assessment scenario.

The risk of an impact on compliance with limit values increases the earlier the assumed opening year for the option. In 2025, the risk is high and the option is likely to impact on zone compliance due to impacts in central London.17

High Court Ruling

15.Both the 2016 and 2017 Air Quality Re-analysis studies published by the Government base their conclusions on the Government’s revised Air Quality Plan, which was published in December 2015. However, on 2 November 2016 the Supreme Court ruled that this plan was based on “optimistic emissions data [and] did not seek to meet the requirements of the Directive as soon as possible” and that the Government must develop a new draft plan by April 2017.18 The Mayor of London, reflecting his fundamental concerns about airport expansion, told us:

It is yet to be demonstrated that an expanded Heathrow could operate without exceeding legal limits for NO2. [...] The requirement for Defra to draft a new Air Quality Plan incorporating more realistic emissions factors is likely to further complicate attempts to demonstrate compliance of an expanded airport.19

16.Hillingdon, Richmond, Wandsworth and Windsor and Maidenhead local authorities argued that the Government should withdraw support for Heathrow expansion and re-model the impacts using the new emissions factors and against the new Air Quality Plan.20

17.In response to our interim report the Government told us they were “carefully considering what this [ruling] means for the airport capacity programme”.21 During our evidence session the Transport Secretary told us that the High Court decision will not affect the Government’s projected timetable. He noted that “it is important to separate these two issues [expansion and air quality]” arguing:

I don’t think that the air quality issue addressed in the Supreme Court and the challenge around reducing levels of NOx is part of the same debate as the Heathrow expansion. The NOx issue, the air quality issue, even around Heathrow itself, is about the traffic on our roads.22

18.The Government published its Draft National Policy Statement on 2 February 2017, it announced that its consultation will last 16 weeks, closing on the 25 May 2017. Given the Government has been given a deadline of July 2017 to complete its new air quality plan, this means the Government will be unable to carry out a full re-analysis of air quality impacts using both the updated COPERT emissions factors and the measures of the new air quality plan within the consultation period.23

Appraisal of Sustainability

19.The Government’s Appraisal of Sustainability was published shortly before this report. We have been unable to provide a full assessment of the Appraisal, however, we would like to highlight some of its conclusions that are of concern to the Committee.

20.The Appraisal argues that the overall concentration of NO2 will remain below the UK’s annual mean objective, however it adds that all the considered schemes for airport expansion would result in “a net increase in population exposure to air pollution”. It estimates, for Heathrow expansion, that an increased 47,063 properties could be exposed to air pollution, by an average of 0.9μg/m3.24

21.The Appraisal also states that Heathrow expansion is “predicted to cause new exceedances of critical levels at the South West London Waterbodies RAMSAR/Special Protection Area and the Wraysbury Reservoir Site of Special Scientific Interest. These impacts potentially result in significant negative effects of internationally designated sites for nature conservation.25

Interpretation of Compliance

22.The Government’s 2016 re-analysis study of air quality interpreted compliance with EU limit values along the same lines as that of the Airports Commission:

If the maximum concentration in a zone is above the limit value and increases with the option or if the option causes the maximum concentration in a zone to increase from a level below the limit to a level above the limit value, the option is considered to impact on compliance within that zone.

In all other cases, the option is not considered to impact on zone compliance. However, in describing the impacts of an option where the zone compliance is unaffected, we distinguish between cases where all road links affected by an option have predicted concentrations below the limit value and cases where options contribute to worsening of existing exceedances of the limit values or create new exceedances without affecting the maximum concentration in the zone.26

23.The Airports Commission’s approach was characterised by critics during our inquiry as allowing air pollution to get worse in some areas, so long as other areas within Greater London were worse.27 Daniel Moylan, argued that road schemes in London were evaluated against a requirement that the scheme should not cause air quality to deteriorate and that this should be the minimum standard.28 Such concerns were reiterated to us by the group of London Boroughs cited above–they told us that they continue to believe that the Airports Commission approach is incorrect and therefore that the reanalysis study “relies on the same flawed test’.29

24.In our interim report we recommended that a view of compliance which could allow air quality to deteriorate “provided it is no worse than the worst link in the zone” would make little sense in policy terms for protecting public health and wellbeing. 30 31 When questioned on whether the Government is working towards this scenario the Secretary of State told us:

We have now been told by the courts to go back and do the work again, and clearly that is going to happen. There are two issues here. One is, yes, there are legal rules to comply to, but secondly, it is also about doing the right thing.32 33

25.In a letter to the Committee after our evidence session the Transport Secretary reiterated that legal NO2 requirements will remain the Government’s measure for UK air quality compliance, but did not provide clarity on the interpretation of legality that the Government intends to use. He told us the “final development consent will only be granted if we are satisfied that, with mitigation, the scheme is compliant with our legal obligations on air quality”.34

26.The updated Air Quality Re-Analysis published 2 February 2017 provided no further comments on the Government’s interpretation of compliance in relation to the EU air quality limits.35

Health Costs

27.In our interim report we recommended that the Government carry out a full assessment of the likely costs of preventing an adverse impact on health from expansion.36 Some London Boroughs agreed with this, arguing that a full Quality of Life Assessment was needed.37 The Transport Secretary told us that the Government will seek to deal with health impacts as “effectively as we can” by stepping up Government support to encourage people to take on new technologies, like ultra-low emission vehicles.38

28.Alongside the Airports National Policy Statement, the Government published its Health Impact Analysis. The purpose of which is to “assist decision makers in judging the impact of airport expansion and its broader legacy to the population’s health.” Regarding the health impacts of air quality, the analysis found that during both the construction and operational phases of Heathrow airport expansion, there would likely be “moderate adverse impacts upon health outcomes, including increased risk of respiratory disease, cardiovascular disease and adverse, short-term temporary and intermittent impacts”.39 and that there would be:

Major adverse impact upon vulnerable groups where health impacts could lead directly to deaths, acute or chronic diseases. These vulnerable groups include children and young people and people living with long-term health conditions may be susceptible to major adverse health impacts.40

Low Emission Technology

29.The Transport Secretary told us that the problem of air quality must be tackled before the new runway becomes operational. When questioned on the significant impacts of air pollution, including the worrying health impacts, he consistently referred back to the effectiveness of Government action encouraging the take up of ‘low emission technologies’ to improve air quality. He stated: “we have to continue, in my view, an across-the-piece strategy to drive the migration of the transport in our busiest urban areas to lower emission technologies”.41

30.The Government’s Updated Air Quality Re-analysis study concluded that:

The level of risk is primarily dependent on the timing of the introduction of, and effectiveness of, measures to reduce emissions from vehicles on the wider road network. It is largely independent of assumptions relating to the impact of the option itself or the direct mitigation of option-related emissions, Impacts near the airport, do not, in general, affect zone compliance.42

31.The importance of reducing vehicle emissions to improve air quality is demonstrated in the Government’s updated air quality reanalysis. However the Government’s reliance on low emission technology as the solution is of concern because we have no confidence that the Government will meet its target for 60% of all new cars to be Ultra-Low Emissions Vehicles (ULEVs) by 2030, as a result of our inquiry into Sustainability in the Department for Transport.43


32.The UK has already breached legal NO2 limits in London for 2017. The High Court has ordered the Government to produce a new plan to tackle air pollution by July 2017, the conclusions of both of the Government’s air quality re-analysis studies are based on the previous, over-optimistic plan. The effectiveness of the Government’s new air quality plan will be integral to determining whether Heathrow expansion can be delivered within legal limits. We are concerned that the timing of the draft NPS consultation means the Government will be unable to carry out a comprehensive re-analysis of the air quality impacts, using the new air quality plan, before the consultation process is complete. The Government must publish such an assessment alongside the final National Policy Statement, it must work towards a scenario in which all road links affected by expansion have predicted concentrations below the limit value. Whilst the health impact assessment is a step in the right direction, the Government must carry out work to reduce the significant health impacts identified, before construction of the third runway begins.

33.Since the Government intends to withdraw the UK from the EU before April 2019, there is no certainty about what our legally binding air quality limits will be after 2019. We are disappointed that these limits are not clearly laid out in the Draft National Policy Statement. We encourage the committee scrutinising the NPS to consider this report and its recommendations, and urge the Government to clarify its position in its response to this report.

34.We are concerned about the Government’s apparent reliance on low emission technology to solve the problem of air quality. We do not consider encouraging people to buy ULEVs an adequate response to the significant health impacts of air pollution and we have no confidence that the Government will meet its 60% target. The Government should work with Defra on an air quality alert system for people who are especially vulnerable to the effects of short-term exposure to pollutants.

Surface Access

35.In a recent report Sustainable Aviation stated that “the primary emission source of concern to UK air quality is road traffic” and that non-airport road traffic in the vicinity of Heathrow airport accounts for 27% of NOx emissions.44 In our interim report we recommended:

Before the Government decides to go ahead with Heathrow expansion it should set out its assessment of what would be required in terms of infrastructure improvements, agreed responsibilities for funding and milestones for completion. This should be part of a wider transport strategy for West London to minimise the risk of unintended consequences. The Government must make a binding commitment that Heathrow will fund the infrastructure improvements.45

36.Heathrow Airport reiterated that road traffic “remains the key contributor to air pollution around the airport”. In their Statement of Principles they note that one of the key drivers for their surface access plan is to “have no more airport cars on the roads” as a result of expansion.46 They plan to achieve this through working to increase public transport mode share to at least 50% and by improving road access to the airport.47 They cited evidence of the Airport’s track record of delivering meaningful improvements in air quality, noting that “over a five year period, ground based emissions of nitrogen oxides from airport activity reduced by 16%”.48


37.There is little agreement on the surface access requirements that are essential for expansion. The Airports Commission estimated £5 billion in total capital costs would be required for surface access, including improvements to the M4, M25, local A-roads and Southern Rail access to Staines.49 Heathrow said, in its Statement of Principles, that it considers the M25, A-road and airport stations works essential to the new runway being operational by 2026 and said it had set aside £1 billion to pay in full itself for these works.50 TfL said it would cost £15–20 billion to fund the total transport infrastructure required.51

38.The Mayor of London was critical of the Government’s approach and Heathrow’s, saying that:

Delivering mode shift will be critical to limiting highway traffic and helping tackle air pollution, but no new rail infrastructure is deemed by Government or Heathrow Airport Limited to be required for expansion, rendering such an aspiration simply not credible.52

39.The Government has yet to publish an assessment of the essential infrastructure requirements for expansion. In its response to our interim report the Government told us that it would set out its surface access requirements in the NPS, and noted that Heathrow had set out a surface access plan and committed to public transport use targets and to no increase in road traffic.53 The Committee has not examined the Draft National Policy Statement in detail, however early impressions are that it does not add further clarity on this question.54

40.In oral evidence the Transport Secretary told us “I understand how it is going to be funded” and strongly criticised TfL’s estimates of £15 billion, saying that he did not “know what you would spend the money on.”55 Documentation released with the announcement of expansion indicated the Government’s support for the Airports Commission’s conclusions that the total cost for surface access improvements would be £5bn, however they are yet to provide their own more detailed estimate.56 The Transport Secretary argued there are two dimensions to the Government’s plan for improving public transport access:

First of all, there are the immediate improvements needed as a result of the runway itself. That is to the various neighbouring roads to the M25, all of which will be borne directly by the airport. Then there are improvements that will be happening anyway, like the Piccadilly line improvement, which will substantially increase capacity on the Piccadilly line, and Crossrail and HS2.57

41.In response to Heathrow’s promises, the Transport Secretary told us that “the Heathrow contribution will be much higher” than the £1 billion they plan to set aside. He also confirmed that the airport’s commitments to deliver no increase in the overall road access to the airport and the proportion of passengers accessing the airport by public transport will be regarded as “mandatory parts of the agreement process.”58 The Airport also said it wanted costs to be “capped” and to be exempt from cost overruns it had not proposed.59 In response Mr Grayling said that any cost overruns on the project itself would be the responsibility of the airport: “as it is a privately funded project, any commitments that they do not get right, they will have to pay for”.60

Accountability and Capacity

42.Identifying the impact of Heathrow on local traffic, and therefore on air pollution, is complex and contested by the airport and local authorities. Our previous report stated:

The Government should not approve expansion at Heathrow until it has developed a robust framework for delivery and accountability. [...]

The Government must establish clearly delineated responsibilities for meeting air quality limits before deciding to go ahead with the scheme. We foresee significant legal challenges further down the line if this is not done, for example, if central Government tried to hold local authorities to account for a failure to meet the [air quality] targets that they attributed to airport expansion or to penalise the airport for pollution that it attributed to background traffic.61

43.In response to questions on responsibility and capacity being dependent on meeting air quality limits, the Transport Secretary said:

Of course we will monitor the overall issue and make sure that the airport is held to the commitments it has made in a variety of different areas, but on-the-ground enforcement for obvious breaches resides with the local authority.62

It depends when and where [a breach should occur]. If it is clearly the case that the airport does not have the ability to deliver the commitments, for example, on road access to the airport, so that we are expecting a huge increase and air quality problems as a result, then no, the airport will not be able to release its infrastructure.63


44.The Government has not yet published a comprehensive assessment of the infrastructure requirements of an expanded Heathrow, including an outline of costs, responsibilities and accountability. The Government must publish such an assessment and consult on it before publishing a final National Policy Statement.

45.We reiterate that we foresee legal and commercial risks down the line if clear responsibilities and accountability for meeting air quality targets are not set out at the beginning of the process. For example, Heathrow have said there will be “no more cars on the road” as a result of expansion. There needs to be clarity over how this pledge will be delivered and monitored, the consequences if it is not met and the implications of that for local authorities’ responsibilities to deliver air quality compliance.

4 ERG, King’s College London, London Air Data; at 21h on 5th January 2017 Brixton Road reported its 19th hour above the EU limit threshold for NO2

5 See Transport for London; Aviation Environment Federation; Communities Against Increased Aviation Noise; Friends of the Earth England and Wales; Gatwick Airport; Twickenham Friends of the Earth.

6 Airports Commission Final Report, page 28

7 Environmental Audit Committee, Airports Commission Report, page 14, para 47, HC 389

8 Environmental Audit Committee, The Future of the Natural Environment After the EU Referendum, HC 599

10 Air Quality Re-analysis Study, Page 6, Para 1.1.17

11 Air Quality Re-analysis Study, Foreword, Page 1

12 Under RDE test, introduced through EU law, a car will be driven on public roads and exposed to a wide range of different conditions. Specific equipment installed on the vehicle will collect data to verify that legislative caps for pollutants such as NOx are not exceeded.

13 Air Quality Re-Analysis Study, Foreword, page 2

14 Written Evidence, para 2.3

15 Secretary of State for Transport, Oral Evidence, 30 November 2016, Q8

17 Ibid. page 2

19 Letter from Mayor of London to the Committee, 17 November 2016, para 6.1; Hillingdon, Richmond, Wandsworth and Windsor and Maidenhead local authorities made a similar point in their written evidence, para 2.3

20 Written Evidence, para 2.16

21 Letter from Chris Grayling to the Chair, 8 November 2016

22 Oral Evidence, 30 November 2016, Q1

25 Ibid.

26 Air Quality Re-analysis Study, Page 6, Paras 1.1.17–18

27 For example, Daniel Moylan, 14 October 2015, Q46

28 Oral Evidence, 14 October 2015, Q48

29 Hillingdon, Richmond, Wandsworth, Windsor and Maidenhead, written evidence, para 2.1

30 Richard di Cani, TfL, Oral Evidence, 30 November 2016, Q41

31 Environmental Audit Committee, Airports Commission Report, page 14, para 43, HC 389

32 Oral Evidence, 30 November 2016, Q41

33 High Court Ruling,

34 Letter from Chris Grayling, 9 January 2017

35 WSP | Parsons Brinckerhoff, Updated Air Quality Re-analysis

36 Environmental Audit Committee, Airports Commission Report, page 11, HC 389

37 Hillingdon, Richmond, Wandsworth and Windsor and Maidenhead, para 2.7

38 Oral Evidence, 30 November 2016, Q42

39 Draft Airports National Policy Statement : health impact analysis, shortlisted schemes, pages 168–177

40 Ibid.

41 Oral evidence, 30 November 2016, Q1

42 DfT, Updated Air Quality Re-Analysis, February 2017, p. 2

43 Environmental Audit Committee, Sustainability in the Department for Transport, HC 184, para. 25

44 Sustainable Aviation, ‘UK Aviation and Air Quality: our contribution, the challenges and opportunities’, pp24,46

45 Environmental Audit Committee, Airports Commission Report, page 17, HC 389

46 Heathrow Airport Limited: Statement of Principles, page 38

47 Ibid.

48 Heathrow Ltd., Written Evidence, para 3.2

49 Airports Commission Final Report, tables 8.2 & 11.2

50 Heathrow Airport Limited: Statement of Principles, page 20, para 1.10.1

51 Oral Evidence, Richard di Cani, 14 October 2015, Q55

52 Letter from Mayor of London to the Committee, para 6.1

53 Letter from Secretary of State for Transport to the Chair, 8 November 2016

54 WSP | Parsons Brinckerhoff, Updated Air quality Re-analysis: impact of new COPERT emission factors and associated new pollution climate mapping sensitivity testing

55 Oral Evidence, 30 November 2016, Q20 & 22

56 DfT, Review of the Airports Commission’s final report, page 17, para 73

57 Oral Evidence, 30 November 2016, Q20

58 Chris Grayling, Oral Evidence, 30 November 2016, Q23

59 Heathrow Airport Limited, Statement of Principles, page 19, para 1.9

60 Chris Grayling, Oral Evidence, 30 November 2016, Q23, Q25

61 DfT, Review of the Airports Commission’s final report, page 16 para. 53

62 Oral Evidence, 30 November 2016, Q28

63 Ibid.

20 February 2017