The Great Heathrow Air Pollution Scandal


1. Introduction

The issue of air pollution has come to the forefront in the last couple of years and it has become a political ‘hot potato’ because of the air pollution impacts that a third runway at Heathrow would have.

This report shows that:

·        Air pollution is an issue of the utmost importance in terms of its effect on human life and health.

·        A third runway at Heathrow would make air pollution appreciably worse than it would otherwise be.

·        The Airports Commission (AC) has systematically played down the air pollution impacts of a third runway at Heathrow.

·        The reason why the AC has under-stated impacts is completely explicable when account is taken the social and political context.

This report is timely and relevant, with a court case involving Plane Stupid just finishing.  The defendants argued that their action in invading the runway at Heathrow was justified in order to avert far greater harm, for example climate change and air pollution.  They argued that the conventional democratic methods were ineffective.  The defendants wanted to have an expert witness on air pollution in order to show how air pollution would be worse with a third runway and to show that the conventional democratic methods were ineffective in preventing harm.  The magistrate refused to allow the witness to appear.


2. The problem  

Air pollution is the UK’s biggest environmental cause of premature death (second only to smoking overall) [i], killing 29,000 people prematurely a year from particulates alone. [ii] However if the effects of the toxic gas NO2 are added, the number of premature deaths is expected to double. [iii]

It is estimated that 9,500 Londoners die every year from air pollution. [iv]

Heathrow is already a massive polluter.  The map below shows how EU and UK air pollution standards – set to protect human health – are regularly breached around Heathrow. [v]

It is a matter of the utmost importance that air pollution levels are reduced.  Indeed, the courts have ruled that this must be done. [vi]

If a third runway is built at Heathrow, there will be nearly 50% more flights and passengers.  It is blindingly obvious that this will lead to an increase in air pollution as compared with two runways.  This in turn will lead to further delay in meeting legal limits and will cause more ill health and deaths.


3. History and context

Expansion or otherwise at Heathrow has been a matter of debate and argument for decades.  It came to the fore in the Rucatse study of 1993 which identified a third runway as an option but did not make a recommendation.

In 1995 a public inquiry into a fifth terminal (T5) commenced.  Air pollution was already an issue and evidence was given by local authorities and Friends of the Earth.  BAA claimed that T5 did not imply any need for a third runway.  Their argument was not believed by the NGOs or councils opposing T5.  However, the inspector, in recommending T5, accepted the argument and said that a third runway should be ruled out.  The government accepted the recommendation on T5 but were equivocal about a third runway.

Almost straight after completion of T5, lobbying for a third runway started.  More detail is available in

‘Heathrow terminal 5 and runway 3: A chronology of worthless promises: 1993-2008’

published by Friends of the Earth.

In 2000 the government issued a Green Paper ‘The future of aviation’.  Following extensive consultations, debate and a Judicial Review, the White Paper was finally issued in 2003 [vii].  Government policy was that a new runway would be needed in the southeast and that Heathrow was the chosen option.  Stansted was the preferred fall-back if a third runway at Heathrow proved impracticable and was also the preferred option for the next runway after Heathrow’s third.

Following this policy statement, the Labour government started to prepare for a third runway.  It recognised that air pollution could be a ‘show stopper’ because air pollution is regulated by EU and UK law, unlike climate change or aircraft noise.

The government carried out air pollution modelling which showed that a third runway would probably be inconsistent with air pollution limits.  The government promptly carried out a new study with more optimistic assumptions and – lo and behold – a third runway would be consistent.  This issue was picked up by the Sunday Times which ran a front page feature and by the BCC which devoted an entire Panorama program to the scandal.

In the run-up to the 2010 general election, in October 2009, David Cameron famously said: “No third runway at Heathrow - no ifs, no buts.” [viii].  In June 2010, soon after the coalition government was formed, Transport Secretary Philip Hammond said: "We have been clear in our opposition to additional runways at Heathrow, Gatwick and Stansted, so the challenge we face now is making them better within existing runway capacity constraints." [ix]

In September 2012 an “Independent Commission” was established with the remit to include, among others, a third runway at Heathrow.  Studies on air pollution were commissioned and are discussed in detail in 3 and 4 below.  The AC’s final report was issued in July 2015.  This is discussed in 5, followed by the latest developments and a consideration of the overall context of the air pollution issue.         

In March 2013 the government published its ‘Aviation policy framework’. [x] As the title suggests, it was not a prescriptive document and said nothing about options for airport expansion.  There was no mention of air pollution in the 10 pages of introduction and executive summary. There is a brief discussion in the section on ‘local environmental impacts’ [xi] but the statements were bland and gave no real indication of the seriousness of the situation. [xii]


4. November 2014 report on air pollution

In Nov 2014 the Airports Commission (AC) issued a report on air pollution which they had commissioned from consultants Jacobs UK Ltd.[xiii]    It is notable that this work only covered the shortlist of sites (Gatwick, Heathrow Northwest NW and Heathrow Extended Northern) which AC had already decided upon. This is telling because it shows how low the AC had in its priorities air pollution and public health.  If those had been high priority, the AC would surely have looked at the air pollution impact of a ‘long list’ of airports and given those impacts significant weight in producing its shortlist.  Instead it leaped to two options in its shortlist which it could not have failed to know would be the very worst in terms of air pollution.

The Jacobs Nov 2014 report covered the present and forecast emissions from Gatwick and the two Heathrow options.  Only the Heathrow NW option is considered here.  The report used results from the Department of Environment and Rural Affairs (DEFRA) Pollution Climate Mapping Model (PCM) which can be used to estimate/forecast the air pollution levels at particular locations.

The estimates of emissions of NO2, PM10 and PM2.5 are shown in the report.  The Executive summary says [xiv]:

UK emissions of NOx are expected to meet current 2020 Gothenburg Protocol targets in both 2025 and 2030. The baseline NAEI 2030 projections are 82.8% of the 2020 Gothenburg NOx targets with the proportion of national emissions increasing to 83.20% with the third runway. While such contributions are likely to be accommodated in the context of the current Protocol targets; there remains a risk that the Protocol targets themselves may become tighter making any accommodation a greater challenge.  

UK National emissions are projected to exceed the Gothenburg targets for PM2.5 emissions in 2025 and remain in exceedance in 2030. Although this is only by a small proportion, without mitigation Heathrow NWR could cause exceedance of the Gothenburg targets to increase 0.12% by 2030.   

Emissions of PM2.5 attributed to associated airport activities in the Heathrow NWR baseline in 2030 represent almost 9% of the projected exceedance of the current 2020 Gothenburg Protocol target without mitigation considered.”   

Table 4.3 of the report [xv] shows that at 2030 that with two runways there would be 11.0 thousand tonnes of NOx emitted, of which 93% is aircraft emissions.  But crucially, emissions from on-airport and other airport-related traffic are excluded.[xvi]  In 2040 the total emissions fall to 10.3 thousand tonnes (kt) and in 2050 to 8.7 kt.  Even without a third runway there would be a steady rise in average aircraft size and number of passengers between 2030 and 2050, so Jacob must have assumed there would be a substantial fall in aircraft emission per passengers.  AEF is not aware of evidence that would support such an assumption and it is surprising that Jacobs (or AC) has not justified in some detail such a key assumption.

With a third runway NO2 emission would be 23% higher in 2030 than without.  This relatively small figure is because the third runway would not be fully used by 2030. [xvii]  When the third runway is full, one might expect the emissions to be about 50% higher than without, on the grounds that flights and passengers are about 50% more.  Mysteriously, emissions are only 34% and 38% higher at 2040 and 2050 respectively, according to Jacobs.      

Table 4.2 [xviii] shows the proportion of total UK annual NOx emissions that would be caused by Heathrow.  The figure is 2.3%.  However, Heathrow is a tiny part of the country and Heathrow’s workforce and its economic activity are also very small in comparison to the UK as a whole.  Therefore 2.3% is a very large amount in relative terms.  It has been stated that Heathrow is the biggest polluter in western Europe.       

On concentrations the report said [xix]The PCM modelling indicates there to be a low to likely risk of exceeding annual mean NO2 EULVs within the Heathrow NWR study area in 2030. The likely risk is identified along the A4 at sections of Bath Road Colnbrook-by-pass.  Projected local monitoring also indicates there to be a low to high risk of exceeding annual mean NO2 AQOs within the same study area. The high risk locations have been identified along the M4, Hillingdon.”

Table 4.6 shows two sites outside the airport which are forecast to exceed UK/EU NO2 limits.  Two other sites are well under the limit as are 4 out of 5 sites in Table 4.7.  However, given that these are roadside sites, the caveat from Jacobs is important: “Currently published PCM projections have been undertaken with the Emission Factor Toolkit (EFT) V5.2c, which was superseded in June 2014 by EFT V6.01. The latest EFT revises overly optimistic uptake rates of Euro VI vehicles in the future fleet mix, which is likely to increase projected emissions and predict higher pollution concentrations. This has been accounted for in Jacobs’ Risk Evaluation for the local assessment. This has been accounted for in Jacobs’ classification of Risk by including NO2 concentrations between 30-36µg/m3 within the low risk category.” In short, their figures are likely to be under-estimates.

App C give an extensive list of sites, very few of which are near the UK/EU limits.  But interestingly, the increases in pollution that would result from a third runway are not shown.  This indicates that Jacobs (and AC) are only interested in staying within legal limits, not in the increases of pollution in the far larger areas where pollution would increase but stay below the legal limits. 

Although air pollution levels may remain below legal limits this absolutely does not mean there are not health, habitat and economic impacts from the increases caused by third runway.  It appears that Jacobs and AC are only interested in what the government can ‘get away with’ in terms of meeting limit values, not in human health and environmental impacts per se.

It can be seen from the above that there are a few locations where limit values are very likely to be breached with a third runway and many more where Jacobs says there is a considerable risk.  Furthermore, there are unanswered questions about certain results which make the achievement of limit values even less certain.

The conclusion that one must reach from the study is that there is little confidence that all the air pollution limits can be met.

It was stated by Jacob that this report was not definitive because the DEFRA PCM model used to assess concentrations is a “static” model.  Jacob consider that a ‘pollutant dispersion modelling’ is needed: “The second stage of assessment to be undertaken, following the publication of this report, will consider pollutant dispersion modelling including the effects of potential government and scheme promoter mitigation measures, and will report on an assessment of receptor impacts and risks to limits and targets.” 

We do not dispute that there are in inadequacies in the static model and a dispersion model could be better.  But an important question is whether the decision to carry out another set of modelling was decided on purely technical/professional grounds.  Or was it because the static model did not give the answers the AC wanted to hear?

Rejecting a Heathrow option on the grounds of air pollution would have been a huge embarrassment to AC and would have infuriated the government.  There would, therefore, have been huge pressure and great incentives to AC and Jacobs to do further work which would show that air pollution is not after all an impediment.

In case this view might be considered to be ‘paranoid’ or a ‘conspiracy theory’, it should pointed out that this has happened before.  In about 2007 the then Labour government decided there should be a third runway at Heathrow.  It carried out air modelling which showed that a third runway would probably be inconsistent with air pollution limits.  The government promptly carried out a new study with more optimistic assumptions and – lo and behold – a third runway would be consistent.  This issue was picked up the Sunday Times [xx] which ran a front page feature and the BCC which devoted an entire Panorama program [xxi] to the scandal.


5. May 2015 report on air pollution

In May 2015 the Airports Commission (AC) issued a further report on air pollution which they had commissioned from consultants Jacobs UK Ltd. [xxii] The timing is most telling.  May 2015 was just a few weeks ahead of the AC’s final announcement and report.  Along with the final report, a series of other documents were published.  The Commission had obviously already decided on its Heathrow NW recommendation and was putting together its final report well before the Jacobs report was published.  It follows that the AC had no intention of taking serious account of air pollution or of Jacob’s latest findings when recommending or not the Heathrow NW runway.

The AC did consult on the Jacobs report and the Aviation Environment Federation (AEF) and West London Friends of the Earth responded rapidly in May 2015.  But as the final report was issued at the beginning of July it is patently obvious that AC could not, in its recommendations, have taken account of AEF’s, WLFOE’s or any other responses except in a cosmetic sense (such as adding some words to clarify statements). 

It is extremely difficult for volunteers and NGOs to assess the air pollution modelling which has been undertaken with a large budget by Jacobs.  We are nonetheless able readily detect major shortcomings in the process which cast severe doubt on the conclusions.  The shortcomings are described briefly below.

We are concerned about the apparent disparity in the results from the Defra PCM model (which is used to assess the possibility of preventing UK compliance with EU limit values) and the local dispersal model (the ADMS-Airport model).  While the Nov 2014 air quality report made clear that the Defra PCM model was a static model while the dispersal model is dynamic, beyond this there is a total lack of explanation of the varying results.  There is not even a comparison of results laid out.  For example, one would have to look at Table 4.6 and App C of the Nov 2014 report with Table 5.5 and Table H1 of the May 2015 report in an attempt to see the differences.  Then one would find most locations cannot be matched up anyway.  Not even being able to clearly see the discrepancies does not engender confidence in the results.

The report states in 3.2: “The contribution of airport emissions to ground-level pollutant concentrations falls off rapidly with increasing distance from the airport boundary, and is very small beyond a distance of a few kilometres.  The “Principal Study Area” for each Scheme has been selected to focus on sensitive properties and habitats likely to be substantially affected by the Scheme and encompasses a 2km radius around each Scheme boundary.”  This statement may be correct as it stands, but it totally misrepresents the impacts further away from the airport.  While pollution concentrations resulting from airport emissions decline progressively as one moves away from the airport, the area and number of people affected progressively increase. [xxiii] In societal terms, a lot a people suffering a small increase in pollution may well be as significant as a small number of people suffering a large increase.  The total impact or societal impact on 8 million Londoners downwind of Heathrow could be greater than the impact on 120,000 people in the study area.

This effect is well illustrated in a report by Barrett et al.[xxiv],[xxv]

3.7 of the report explains that only emissions from aircraft below 915 metres have been modelled.  However, aircraft rise rapidly above this height and they spend the vast majority of their time in this country over 915m.  The fact that they are over 915m does not mean they do not cause pollution at ground level.  What it means is that the pollution is spread over a wider area.  The vast majority of pollution emitted by planes that are higher than 915m (but which come from or are going to Heathrow) is probably deposited in areas well away from Heathrow.  This pollution, probably affecting millions of people, is ignored Jacobs and AC.

We note that all the values in Table 5.5, H1 etc are just ‘spot’ values.  There is no attempt to provide error limits or confidence limits.  Without these it is impossible to validly make statements such as there would be no exceedances. [xxvi]  If for example one had an estimate of 35 ug/m3 for a site and the confidence limit was +-10, there would be a very significant chance of the limit value of 40ug/m3 being exceeded.  This is not good enough when human health and the law are concerned.

There is great over-emphasis on exceedance or not of UK/EU limit values.  The health impacts of air pollution increase as air pollution levels go up and there are no known thresholds below which there are no impacts.  Although air pollution levels may remain below legal limits this absolutely does not mean there are not significant health, habitat and economic impacts from the increases caused by third runway.  It appears that Jacobs and AC are mainly interested in what the government can ‘get away with’ in terms of meeting limit values, not in human health and environmental impacts per se.

While the dispersion modelling suggests there would be no exceedances in 2030, the rules for determining compliance require that ‘national’ model is used.  The national model is DEFRA’s PCM model, Jacobs’ dispersion model being a local model.  Using PCM there is one receptor – at Bath Road – which would exceed the limit.

Possible delay to compliance to the EU limit values is discussed in 5.4.4.  Most of the very highest levels or air pollution now and in 2030 are forecast to occur in central London, particularly Marylebone Road.  Jacobs’ interpretation seems to be that all one need do is to bring the pollution at Bath Road down to less than Marylebone Road [xxvii], however high the latter is, and then there is no delay in compliance.  Therefore pollution would not be an impediment to a third runway.  AEF does not believe that playing off a single site against another in this way to demonstrate compliance is the EU’s intent.  Neither does the Environment Audit Committee and nor does Campaign for Clean Air in London’s legal advisor. [xxviii] 

Associated with the great over-emphasis on exceedances, there is great under-emphasis on changes in air pollution at all the locations which would not exceed limit values.  A third runway would increase pollution for nearly everyone in the area.  Jacobs estimates populations subject to increases of pollution at 122,000 by NO2 and 121,000 by PM10.[xxix]  But these populations are only the ones in the ‘Principal Study Area’ – there will be much larger populations outside that are also impacted.  Because there are health and mortality impacts well below limit values, it can be safely assumed there will be adverse health impacts for a very considerable population beyond the 122,000 and 121,000.

The EU directive does by any means regard just exceedances as important.  It regards maintaining and improving air quality as important too. [xxx]  AC’s stated objective is “improve air quality consistent with EU standards and local planning policy requirements. [xxxi] The National Policy Framework is even stronger: “Planning policies should sustain compliance with and contribute towards EU limit values .. [xxxii]          

Jacobs shows that air pollution levels would go up almost everywhere with a third runway, contradicting UK policy and AC objectives.  Jacobs and AC clearly believe, although they do not state it as such, that it is all right to appropriate any reductions in air pollution that would result from other action (such as cleaner cars) and offset them by increases due to a third runway – as long as there are not exceedances.

There is no discussion of the morbidity and mortality due to air pollution from Heathrow and a third runway and no presentation of results. [xxxiii]  Since the major concern about air pollution is human health, this omission is very concerning.

There has been some work on the subject.  In 1988, it was estimated that that the death toll arising from Heathrow’s air pollution was about 57 pa and that a fifth terminal would be add about 17.[xxxiv]  This evidence was not disputed.  In 2010 a report was produced [xxxv] by MIT and Cambridge.  It says: “If a third-runway is built at London Heathrow, early deaths due to emissions from Heathrow increases from 110 to 150.” [xxxvi]  It should be noted these only refer to deaths, not ill-health that does not lead to death.

One can only surmise that Jacobs and AC want to confine discussion of air pollution to an abstruse technocratic exercise, not highlight the real human issues that ought to influence the decision.

As well as EU limit values, there are a series of ‘guidance values’ for pollutants recommended by the World Health Organisation.[xxxvii]  The UK may not be obliged by law to meet these values, but it is remarkable they are not even mentioned in the ‘legislation and policy context’ section of the report.  These guideline values would most certainly be breached in some locations with a third runway.  One strongly suspects this is why Jacobs and AC have kept quiet about them.

Table 5.9 shows that almost half of all the ‘designated habitats’ in the vicinity of Heathrow would be subject to breaches of limit values for NO2 with two runways.  In almost every case, a third runway would make things worse.  Jacobs states that a third runway would only cause one new exceedance [xxxviii] but fails to mention that this is because most of the sites will be over the limit even with two runways.

After Table 5.9 Jacobs says: “The macroscale siting criteria in the Directive states that sampling points for the protection of vegetation and ecosystems should be sited  a) more than 20 km from an agglomeration (about 250,000 people), and b) more than 5 km from Part A industrial sources, motorways and built up areas of more than 5,000 people.  The UK Government interprets this to infer that the critical level for NOx does not apply within these areas.”  This is a blatant attempt by the UK government to disregard the effects of air pollution on ecosystems.  If applied, it could rule out a large majority of the country’s ecosystems on the grounds they are near a small town or a polluting industrial site or a motorway.  It is doubtful that this interpretation would be upheld in court and it is most certainly not within the spirit of EU law.

The forecasting of the impact of third runway on air pollution levels and the tables and discussion all relate to 2030.  But a third runway would only come on stream at about 2025 and it would by no means be fully used.[xxxix]  The full impact of growth on air pollution would only be seen when the runway is filled up.  Showing only 2030 impacts blatantly misrepresents the air pollution impacts of a third runway.    

In addition to the annual average of 40ug/m3 for NO2, there is a UK/EU limit values for 1 hour means of 18 occurrences each year  [xl]  The Jacobs report says of this standard: “The 1-hour mean Limit Value/objective for NO2 that is cited in Tables 2.1 and 2.2 has not been explicitly considered.  It is extremely challenging to predict 1-hour mean concentrations with any certainty, and the annual mean limit value/objective is more stringent.  Reliance is thus widely placed on an empirical relationship between the two metrics, whereby if the annual mean NO2 concentration is less than 60 µg/m3, there is little risk of exceeding the 1-hour mean criteria. 

It may be the case that this assumption of no exceedances is justified but given the importance of the issues – it is one of just two limit values for most problematic pollutant – this explanation is inadequate.  The consultees surely deserve more than a single ‘throwaway’ paragraph that gives no explanation of who places reliance on the assumption and on what basis they do so and does not even provide references.

There can be no doubt that hourly exceedances are a significant issue.  One site in London had 1537 breaches in 2015 compared with the limit of 18! [xli] The limit for the whole of 2016 was breached by 8th Jan.  Other sites are following closely behind. [xlii]  The annual average for this site was well over the limit at 123ug/m3 so this statistic does not of itself disprove Jacobs’ assumption.  But an 85-fold exceedance of the hourly limit when the annual average is only exceeded 3-fold must cast doubt on the assumption.  

Because there could be exceedances using the PCM model, Jacobs considered a number of possible mitigation measures (5.7.1 on page 81).  The attempt is laudable but a striking feature is that while they were able to suggest measures, they could not estimate the impact of most of them.  Those measures that they have quantified make little difference – well under 1ug/m3 for most.  Perhaps more significantly, the most important measures are unlikely to be politically deliverable.  Congestion charging is anathema to the government (whereas road building is supported.)  A charge or tax on NOx is very unlikely for governments that are seeking to reduce tax in the form of Air Passenger Duty, despite aviation already being massively under-taxed compared with other sectors of the economy.


6. Airports Commission final report

In July 2015 the AC made its final report.  It recommended, as most people expected, a new runway at Heathrow.  

The report had an appreciable significant section on air pollution, euphemistically called “air quality”.  It used the Jacobs reports to promote the view that air pollution should not be an impediment but did not include important qualifications and nuances in Jacobs that would call into question the recommendation.  Nor did AC highlight any of major flaws that we have described above.

The major flaws and omissions in the AC final report may be summarised as follows.

AC just concentrates on meeting EU legal limits. That is, what the UK can get away without legal action.  It ignores the deaths and ill-health as issues in their own right, even though air pollution at well below EU legal limits has health and other impacts.

AC considers that as long as EU limit values are achieved, the potential health benefit of reduced air pollution from non-airport sources can be appropriated by extra pollution from a third runway.

AC recognises that delay in compliance with European law could be an impediment but interprets this to mean that extra pollution from Heathrow, however great, would not matter as long as one on other site, probably in central London, remained even worse.


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 new runway – a fully used runway – is not shown.


Almost half of all the ‘designated habitats’ in the vicinity of Heathrow would be subject to breaches of limit values for NO2 with a third runway.  AC meekly accepts the government’s view that these should be ignored.     


Hourly limit values have legal force along with annual averages.  These are not mentioned, apart from a ‘throwaway’ sentence in a Jacobs report.


Mitigation, ie action to bring air pollution levels down to within legal limits with a third runway, are discussed in the final report. [xliii]  But they are little more than a set of ‘good ideas’.  They have not been assessed for financial, social or political deliverability and were not recommended.



7. Legal challenge to UK government

On 29/4/15 The UK Supreme Court quashed the Government’s “ineffective plans to cut illegal levels of air pollution in Britain” and ordered it to deliver new ones by the end of the year.  The Supreme Court Justices were unanimous in their decision, saying: “The new Government, whatever its political complexion, should be left in no doubt as to the need for immediate action to address this issue.  The ruling was the culmination of a five year legal battle fought by ClientEarth.[xliv]

In Dec 2015 the government published a new air quality plan.[xlv] ClientEarth considered that the plan was unsatisfactory: “These plans are an outrageous statement to the Supreme Court essentially stating that the government doesn’t intend to comply as soon as possible. It is an arrogant response that is simply not good enough.”  ClientEarth concluded that it will have to make a legal challenge to force the Government to take faster action to achieve legal pollution limits.[xlvi]

The fact that the government has been taken to court is highly relevant.  This affair will have been watched closely Jacobs and AC.  They could not have failed to conclude the government does not want to be pushed into implementing the EU air quality directive. Nor could not it have failed to occur to them that one of the reasons why the government was resisting on air pollution in London is because of Heathrow expansion.  There was a pretty strong message, albeit inferred and most certainly not written, that the government did not want or expect the Commission to reject Heathrow expansion because of air pollution considerations.


8. Environmental Audit Committee

In December 2015 the House of Common Environmental Audit Committee published a report on its investigation into the environmental impacts of Heathrow expansion.  [xlvii]      

It found, independently of ourselves, the same three major flaws in the AC’s work that we had found earlier. 

Para 43: “Many of our witnesses interpreted the Commission’s interpretation of the Air Quality Directive as implying that significant increases in NO2 resulting from Heathrow expansion would be allowable because of worse performance elsewhere in London. This would make no sense in terms of protecting public health and wellbeing. The Government should make clear that this is not the position it intends to take when assessing the scheme for compliance with the Directive.”

Para 47: “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 plan to be approved by the European Commission. It will also need to show that 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 allowed to expand.”

Para 50: “The Commission recommended that the release of capacity at an expanded airport should be conditional on air quality standards being met. The Government should not approve expansion at Heathrow until it has developed a robust framework for delivery and accountability. This should have binding, real-world milestones and balance the need for investor certainty with assurances that a successor Government cannot set the conditions aside if they become inconvenient.”


9. Government position (as at January 2016)

Following the AC final report in July 2015, the government indicated that it would respond by the end of the year.  The government statement on 10th December said it supports the building of a new runway in the south east, to add capacity by 2030 (earlier airports claimed they could have a runway built by 2025). However, the decision on location is “subject to further consideration on environmental impacts and the best possible mitigation measures.”  All three short listed schemes will continue to be considered.


It is almost certain that air pollution is a major reason for deferring a decision.  It is probably the only real ‘show stopper’.[xlviii]  It is extremely likely that government experts, including lawyers, have advised that a new runway at Heathrow would be wide open to challenge in the UK courts and from the EU.   


10. The political context

Air pollution from Heathrow is not a technocratic issue, isolated from everyday life.  The issue can only be interpreted by reference to the sider social, economic and political context.  A whole book could - and should - be written about the non-technical aspects of air pollution.  There follows here the briefest of analysis.

In October 2009 David Cameron said: “No third runway at Heathrow - no ifs, no buts.” [xlix].  In June 2010, soon after the coalition government was formed, transport secretary Philip Hammond said: "We have been clear in our opposition to additional runways at Heathrow, Gatwick and Stansted, so the challenge we face now is making them better within existing runway capacity constraints." [l]


However, these statements did not prevent heavy lobbying from industry and Conservative MPs for airport expansion.


An “Independent Commission” was established in September 2012.  The government appointed an ‘establishment’ figure, Sir Howard Davies, as part-time chair and four establishment and virtually silent part-time commissioners.  The detailed work was devolved to a secretariat drawn mainly from the DfT (Department for Transport).  Those staff returned to their roles at DfT after the Commission’s work finished.


This chronology of events demonstrates that David Cameron was prepared to renege on his Nov 2009 promise.  If he had been determined to stick to his promise, he could have still established a commission, but one whose remit excluded a third runway at Heathrow. 


As the only airport in the country nearly full to capacity and having by far the highest forecast future demand, Heathrow was always likely to be the airport recommended for expansion.  The implicit change in policy – from ruling out to supporting or at least accepting Heathrow expansion - could not have failed to be noticed by those involved, not least Howard Davies, the Commissioners and the consultants employed by AC.  This, then, is the context in which all the AC’s work was conducted.


Sir Howard Davies is a conventional economist and his biography shows [li] that he is greatly favoured by government.  In appointing him yet again to a prestigious and high-profile post, this time as head of the AC, David Cameron clearly regarded Davies as a ‘safe pair of hands’.  Given the government’s prioritising of economic growth and its lack of interest in environmental issues such as air pollution and climate change, it does not take a political scientist to realise that the government did not want or expect AC to rule out new runways or a new runway at Heathrow on environmental grounds.  Davies was just the person to not do so.


If Davies had recommended against a new runway on environmental grounds, the government and sections of the business community would have been furious.  It is inconceivable that Davies would have been offered any further government commissions.


The contrast with another prominent economist, Sir Nicholas Stern, could not be more marked.  Stern produced a seminal report showing how the economy could be seriously impacted by climate change.  Having spelled out this truthful but politically unpalatable message, he was sidelined by government.


If is also apparent that if Davies had come out with the ‘wrong answer’ he would not have been favoured by the private sector.  It is inconceivable that someone with strong and radical messages about air pollution and climate change and who challenged the primacy of economic growth and claims about what really generates growth, would be appointed as chairman of a large bank.


The four commissioners, thought largely silent and un-noticed by the public, will also be seen to be establishment figures, with a history of public or public sector appointments and no history of controversial views.  It is notable that not one of them dissented or chose to speak out about any aspect of the AC’s findings, despite the extremely suspect conclusions on air pollution, climate change, economics, etc.  They too would have lost favour with government had they spoken out.


As noted above, most of the secretariat of AC were seconded from DfT.  They are civil servants and are now back again as servants to their DfT seniors and to the Minister of Transport.  For them to highlight evidence, let alone argue a case against a third runway, when the political mood was so obviously in favour, would have been a career-limiting move.


The consultants too had strong reasons to not to ‘rock the boat’.  Air pollution consultants depend to a great extent of work given to them by developers and businesses who employ them to show that air pollution should not be an impediment to their scheme. A consultant who signalled air pollution problems any more strongly than s/he absolutely had to [lii] would rapidly discover work drying up and would be unlikely to get any more government contracts.


This above analysis shows clearly that all the major parties in the inquiry had strong reasons not to promote evidence that would undermine recommendations for a new runway in southeast or a third runway at Heathrow.  In no way, therefore, was the AC genuinely “independent”.    


With no confidence in the AC and a one-sided multi-million pound propaganda campaign by Heathrow, one should not be surprised that NGOs and committed individuals feel they need to represent the concerns and rights of ordinary people in whatever way they can.  They have been deprived of any meaningful hearing by AC or government and do not have deep pockets to pay for public relations campaigns.  The question that arises is a profound one for them, for public policy and for democracy.  Should people who feel they have no alternative but to resort to non-violent direct action be criminalised for doing so?


Nic Ferriday, for West London Friends of the Earth

January 2016  



[i]  Healthy Air Campaign - air pollution, the problem:

[ii]  Committee on the Medical Effects of Air Pollutants/COMEAP – 29,000 premature deaths attributed to long-term exposure to man-made particulate air pollution per annum:


[v] The Heathrow area in 2010 breaching the NO2 annual legal limit (all areas yellow to red are breaching legal limits). Source: (2010 is shown “because it is the latest year for which an accurate model is available.”)

[vi] The Supreme Court ruled that that the UK Government must draw up a new action plan by the end of 2015 to tackle air pollution and ensure that the period of failure to comply with the EU limit values for air quality is ‘as short as possible’.  Press summary of the ruling is available here:

[vii] ‘The future of air transport’. December 2003. Incomplete URL: 


[xi] Ibid paras 3.47 to 3.52 on pages 64, 65. 

[xii] For example “The Government assesses the UK’s compliance with the EU air quality limits and target values. Air quality monitoring is also carried out by local authorities to support their local air quality management objectives. PM limits are largely met, but challenges remain with nitrogen dioxide,” (para 3.50).  “Studies have shown that NOx emissions from aviation-related operations reduce rapidly beyond the immediate area around the runway. .. The Government expects them [airport operators] to take this responsibility seriously and to work with the Government, its agencies and local authorities to improve air quality.

[xiii] Jacobs.  6. Air Quality: National and Local Assessment. Prepared for the Airport Commission. November 2014.

[xiv] Ibid page iv

[xv] Ibid p48. Table 4.3 Heathrow NWR annual mass emissions by source. 

[xvi] There is an estimate of ‘fugitive emissions’ which are leaks and other irregular or unintended emissions.  But these will be very small compared with regular engine emissions and only represent 2% of the quoted Heathrow emissions.  

[xvii] More precisely, the 3 runways together would not be used to capacity.  It is not possible to say how heavily each individual runway would be used.   

[xviii] Ibid p46. Table 4.2.

[xix] Ibid page iv

[xx]  ‘Cabinet split over proposed Heathrow third runway’.  “The Sunday Times has revealed how the official data was manipulated by BAA, the airports operator that owns Heathrow.”

[xxi] ‘Friends in high places’. 21/7/08.

[xxii]Module 6: Air Quality Local Assessment. Detailed Emissions Inventory and Dispersion Modelling. Prepared for the Airports Commission. May 2015’.

[xxiii] The area within a radius x of a pollution source increases as the square of the radius.  Therefore the area within 4km of the source is 4 times as great as the area within 2km.  The population impacted will be correspondingly greater.

[xxiv] Air quality impacts of UK airport capacity expansion.  Steven Barrett, Steve Yim, Marc Stettler and Sebastian Eastham.  A report by the Laboratory for Aviation and the Environment at MIT in collaboration with the Energy Efficient Cities Initiative at Cambridge University.  Page 3

[xxv] The diagram shows the effects of UK airports generally, not just Heathrow.  But the spreading out of pollution for individual airports at progressively lower levels but over progressively larger areas is well shown.

[xxvi] 5.4.3 page 64 states: “There are no predicted exceedances of the air quality objective at any receptor location, in either the Do-minimum or Heathrow NWR scenarios. 

[xxvii] Para 5.7.1 on page 80:As it is concluded that the Heathrow NWR would delay compliance with the Limit Value, the potential benefits of these measures (in terms of changes to annual mean NO2 concentrations) at the Bath Road link, where the PCM model predicts the highest concentration in 2030, are summarised in Table 5.16.

[xxix] Jacobs Mar 2010 report, Table 5.6 on page 65.  

[xxx] Directive 2008/50/EC says member states should “endeavour to preserve the best ambient air quality consistent with sustainable development”. 

[xxxi] Para 9.2 on page 167 of the AC’s final report.

[xxxii] NPPF says: “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.  Planning decisions should ensure that any new development in Air Quality Management Areas is consistent with the local air quality action plan”.  Quoted in Jacobs report para 2.2.5 on page 16.  It should be noted that no evidence is given by Jacobs that a new runway or associated infrastructure would be consistent with any of the relevant councils air quality action plans.    

[xxxiii] The economic impacts assessment takes account of morbidity and mortality, but the figures are not visible or accessible. 

[xxxiv] Evidence presented by West London Friends of the Earth: ‘Inquiry note FOE/128.  Deaths from air pollution as a result of T5.’ 

[xxxv]Air quality impacts of UK airport capacity expansion.  Steven Barrett, Steve Yim, Marc Stettler and Sebastian Eastham.  A report by the Laboratory for Aviation and the Environment at MIT in collaboration with the Energy Efficient Cities Initiative at Cambridge University.  

[xxxvi] Ibid.  Section 3 on page 4. 


[xxxviii] Page 68, under Table 5.9.

[xxxix] See footnote xii.

[xl] See Table 2.2 on page 16.

[xli] London Air at Kings College


[xliii] Final report 9.84 to 9.88.


[xlvii] The Airports Commission Report: Carbon Emissions, Air Quality and Noise.  At

[xlviii] There are no legal controls on aircraft noise.  There is act which regulates climate-changing emissions, but the Act, and the ‘budgets’ can be changed by the UK government and the government can also interpret the targets to exclude emissions from international aviation.  There is no law about the veracity or rigour in claims about economic benefits, jobs, etc.  A Judicial Review on any of these issues would have to rely on case of a decision being “irrational”.  The bar is set extremely high for such a challenge.     

[li]  “Davies was employed by McKinsey and Company from 1982 to 1987 after working at the Treasury and the Foreign and Commonwealth Office, which included a posting of Private Secretary to the British Ambassador to France.[3] From 1985–86 he was Special Advisor to Chancellor of the Exchequer Nigel Lawson. From 1987–92 he was Controller of the Audit Commission. In 1992 he was appointed Director General of the Confederation of British Industry, a position he held until 1995, when he was appointed Deputy Governor of the Bank of England. In 1997 Davies was appointed Chairman of the newly established Financial Services Authority, serving until 2003.”  From Wikipedia. 

[lii] Consultants have to be careful not be too cavalier in supporting their clients’ objectives when the evidence is dubious.  Otherwise, they would could lose their professional reputation and risk their clients’ scheme being appealed against or judicially reviewed.  However, that does not prevent their reports being unbalanced and slanted in favour of their client.  Academic papers routinely have 3 features that go a long way to ensure that they are rigorous, balanced and transparent.  They are:
a) naming the authors
b) peer review
c) declaration of actual or potential conflicts of interest

The Jacobs reports did not, as far we can see, have any of those.