Minutes of the meeting held on Friday 13 October 2006

Present:

Chairman: Professor J G Ayres

Members:

Prof. D Laxen
Prof. D Derwent
Prof. D Strachan
Prof. V Stone
Prof. P Poole-Wilson
Mr B Armstrong
Prof. D Walters
Prof. R. Harrison
Dr T King
Mr F. Hurley (QUARK II sub-group)
Mr J Stedman (QUARK II sub-group)
Prof. R Anderson (QUARK II sub-group)

Secretariat:

Dr R Maynard
Dr H Walton
Mrs I Myers
Ms I Mills
Mrs J Cleverly

Assessor:

Dr L Newport (DH)
Dr T Williamson (Defra)

ITEM 1. OPENING REMARKS, APOLOGIES FOR ABSENCE AND ANNOUNCEMENTS

1. Apologies for absence were received from Prof. P Burney (QUARK II), Prof. S Holgate, Prof. K Donaldson, Mr R Alexander (Welsh Assembly), Mr N McMahon (Northern Ireland).

2. The Chairman welcomed Mr John Stedman, Prof. Ross Anderson and Fintan Hurley who were attending due to their involvement with the QUARK II report and Mrs Janice Cleverly who had recently joined the HPA and who would be running the expenses and appointments side of COMEAP. The Chairman also welcomed Dr Louise Newport who would regularly attend COMEAP as an Assessor from DH. The Chairman also advised Members that Ms Jackie Maud had left the Environment Agency and that Albania Grosso would now be attending as an observer in her place.

3. Members were informed of the following changes to the membership of COMEAP: Profs. Vicki Stone, Duncan Laxen and Dick Derwent had all accepted an invitation to sit for a further 3 years on the Committee. The Chairman thanked them for their continued support.

4. The Chairman reminded Members to declare any interests they may have.

5. The Chairman reminded Members to submit their expenses claims forms and thanked Mrs Cleverly for setting up the new system (due to the move of the Secretariat to the HPA) so quickly. The Chairman handed over to Janice Cleverly to provide further information regarding the new system to Members.

6. Mrs Cleverly informed Members that the new system was now in operation and that Members who had returned their forms for entry onto the system should expect payment, all things running smoothly, on the 25th October. This would take into account any back-logs which had accrued during the handover of the Secretariat from DH to the HPA. Members were thanked for their patience.

7. The Chairman thanked Mrs Cleverly for her update and reminded members that questions or queries relating to expenses, should be sent to Janice.

ITEM 2. MINUTES OF THE MEETING HELD ON 24th February 2006

8. The Chairman took Members through the Minutes of this meeting page by page. Members agreed that the minutes were an accurate record of the meeting once the following changes had been made:

a) Paragraph 16: add the word 'relative' before 'paucity'
b) Paragraph 30: Check with the named member that they are happy with being named in this instance.

9. Dick Derwent drew Members' attention to his book, recently published by the Environment Agency 'Air Pollution A to Z' and informed the Committee that he was happy for members to contact him for copies of the book or for further information pertaining to it. The Chairman thanked Dick for his advice.

ITEM 3. MINUTES OF THE MEETING HELD ON 23RD JUNE 2006

10. The Chairman took Members through the Minutes of this meeting page by page. Members agreed that the minutes were an accurate record of the meeting

11. One Member noted that in the minutes of the 24th February, reference had been made to the papers by George Knox, which the Committee had discussed on this occasion. In the minutes of the 23rd June, further investigation into these papers had been raised as an action. The Member requested a further update on this matter. The Secretariat were able to confirm that a letter had been sent to Professor Paul Elliot although no response to date had been received. It was agreed that the Secretariat would follow-up the matter.
ACTION: SECRETARIAT

12. Duncan Laxen provided Members with an update on the work of the Roadside Exposure sub-group. Members were informed that things were moving with this group albeit slowly. A Defra contract had just gone out to tender for work which would follow up findings from the work led by Professor Mike Ashmore. It was hoped that there would be a seminar next spring which would focus on the measures of exposure and the relevance of using background sites for better quantification of exposure.

ITEM 4. MATTERS ARISING

Annual Air Pollution Meeting
13. Members were informed that the Annual Air Pollution Meeting, to be held at Cranfield University, would take place on the 1st and 2nd May 2007.

COMEAP Meeting Dates 2007
14. The following dates were confirmed for COMEAP meetings in 2007:

23rd February (London)
22nd June (Didcot)
12th October (London)

Buncefield Fire Statement

15. Members were reminded that their statement on the Buncefield Fire had been placed on the COMEAP website.

ITEM 5. QUARK II MORTALITY REPORT

16. The Chairman raised this item and suggested that the Committee focus on key sections while going through the report. He handed over to the Chairman of the sub-group who thanked its members for their contributions, indicating that they performed well. He noted that members were well informed about the issues covered in the report and that they were able to make judgements about the evidence. He also noted the contributions made by the Secretariat.

17. COMEAP's Chairman opened the floor for general comments regarding the report. Members expressed the following:

• How will the recommendations of the report be used? It was thought necessary to place the recommendations in appropriate contexts as many will use the recommended coefficients to express various outcomes, such as years of life lost. It was thought important for key points, such as the distribution of risk across the population (the size of an individual's risk and risks across susceptible groups), to be communicated.
• The Secretariat, along with the sub-group's Chairman, indicated that a small group had already been established to calculate the health impact on mortality and life expectancy of changes in air pollution (in this case particles). This work is to be presented to COMEAP at a later stage (2007) and will be written as a supplementary paper to this report. However, this paper will not include the distribution of risk across the population. It was flagged up that the method used for calculating health impact is not new and this method was previously agreed and used by the Committee. The Chairman of the subgroup broadly agreed with this suggestion, however indicated that detailed assumptions (for example, those regarding life expectancy) must be well thought out.
• The Secretariat, along with a few members, pointed out that it was difficult to comment on the distribution of risks in the population and that they were unaware of evidence that could help with this issue. It was suggested that one could hypothesise that all members of the population would not be affected to the same degree. One member found the notion of vulnerability attractive, however, it depended on the methods used for identifying these populations. Various assumptions, which the Committee had not considered, may be required in expressing various outcomes. The Secretariat still thought it difficult to estimate susceptibility. They indicated that for those dying from cardiovascular disease, the Committee could not identify those individuals who died as a result of exposure to air pollution.
• The lay-member thought that the report lacked clarity and elegance as it contained too many long sentences and repetition. This was noted by the Secretariat who indicated that the report still required a final edit. The Chairman of the sub-group indicted that the repetition was deliberate and intentional as it was thought useful in covering specific topics in the report.
• Others thought it was a gripping read and indicated that the report must be followed-up by one on public health impacts. It was flagged up that it should include what it could mean for the distribution of effects in the population. Others agreed with the suggestion to include implications regarding the distribution of effects in the population and that other known risk factors (for example, hypertension) should be considered.

18. COMEAP's Chairman then took members through the report, where the following suggested changes arose (unless stated, the Secretariat will take action on items arising from the discussions regarding this report):

i. P. 3, line 22: "potential impact on mortality" - there is a need to indicate that further work on total impacts is to follow.

ii. P. 3, line 33: consider a full stop after the word "mortality".

iii. P. 3, line 41: consider replacing "we advise against attempts" with "we do not intend to make any recommendations in favour of".

iv. P. 4, line 13: add "the effects of" after "between".

v. P. 8, line 25: consider adding a section heading titled "Evidence since 2001".

vi. P.14: define the term relative risk. Consider explaining why the relative risk (RR) for all-cause mortality is not the sum of the RR of cardiopulmonary and lung cancer. Consider placing definitions and explanations earlier, i.e. chapter 1.

vii. P.15, lines 42/43: let the sentence read "…and these are examined in depth in Chapter 3".

viii. P.15, line 46: note that the report's conclusions are given in chapter 4.

ix. P.16, Table 2.2: consider presenting percentages as relative risks. This will allow for consistency across presentation methods or alternatively, indicate that 13% is 1.13 expressed as a RR. Amend footnote d to make clear 'percentage' and RR are not identical.

x. P.20, lines 41-43: that sentence should contain some biological information to indicate that the PM2.5 fraction of particles represents the fraction most likely to be deposited deep in the lung.

xi. P.21, Table 3.1: make it clear in the title of the table that the RRs are presented for the 'study mean concentrations' (as it is not the 'raw' concentration range). Also, place text of footnote 5 (on this page) directly under the table.

xii. P.21, Table 3.1: why is PM10 not included in the table? Readers may question whether PM10 is a better metric than PM2.5. Data for the PM10 metric was not available in the early measurement period (1979 - 83), however their (USA) measurement methods changed in later years. Consider adding PM10 and doing a comparison of PM10 and PM2.5 for the later measurement period for which data is available for both.

xiii. P.21, line 13: reword sentence to include some scientific validity.

xiv. P.22, Fig. 3.1: clearance and a costing has been provided by the publisher. Payment will be arranged via the Secretariat's Administrative Office.

xv. P.23, Fig. 3.2: better figures are available for the Six Cities study, which the Secretariat may wish to use; an appropriate reference will be provided by a member.

xvi. P. 24, question (iv): consider rewording the question.

xvii. P. 24, line 35: tidy "in question (xi) and in Working Paper 1". Make clear that 'the later section' refers to question (xi).

xviii. P. 26, question (v): Mort Lippmann's work on the variation in toxicity being dependent on nickel concentrations may be relevant to this section of the report. It was thought that his work could provide information regarding the active component of fine particles (PM2.5) and an explanation regarding the toxicity of sulphate.

It was flagged up that although nickel is an active species in the ambient aerosol, its contribution to toxicity is unclear. A full understanding of its contribution would require a detailed look at the evidence. As such, the Secretariat thought it possible to have a box indicating that this evidence was received late in the development of the report, but that it strengthens the view currently in the report.

The Secretariat should write to Lippmann to determine the publication status of his material.

xix. P. 33, Box:

• Consider leaving box on a separate page.
• Some members thought it interrupted the reading and suggested that an indication should be given, at the outset (in chapter 3), that a series of boxes will appear later on.
• Replace "interim recommendation" with "conclusions thus far" or "working conclusions".

xx. P.37, Fig. 3.4: consider placing this diagram on a separate page. Members gave suggestions of studies that could be added.

xxi. P. 42, Box: see comments above regarding the box on pg 33.

• Last paragraph of that box - delete "is a reasonable conclusion of our deliberations and has the advantage that" .
• Note that the CLRTAP refers to a convention for Europe.

xxii. P. 43: delete comment box.

xxiii. P. 44, line 46: replace "cardiovascular" with "cardiopulmonary".

xxiv. P. 46, line 16: replace "confidence" with "uncertainty".

xxv. P. 46, line 18: replace "the best estimate of the true coefficient came to lose statistical significance" with "our uncertainty includes the possibility of no effect".

xxvi. P. 46: delete comment box.

xxvii. P. 54, lines 26-31: Secretariat to re-consider wording with the sub-group's Chairman.

xxviii. P. 55, line 49: replace "no evidence of a threshold of effect" with "that the evidence did not point to a threshold".

xxix. Pp. 57/58: place paragraph 4.20 before 4.18

Broad topics in need of change:
1. Lag-times (p. 44, question (xv)): lines 40-46 - members thought that in view of the Secretariat's rough calculations , the sentence regarding a large proportion of benefits occurring in the 1st five years (line 45) after a reduction in air pollution should be weakened. However, they were unclear as to how weak the new text should be, given a proportion of the benefits did occur in the 1st five years of the evidence considered (Clancy et al 2002; Hedley et al, 2002).

It was noted that one difficulty was whether the intervention from the Dublin study is comparable to the ACS study. The calculations suggested that = 50% of the benefits were seen in the 1st five years. Quantification of the short, medium and long-term benefits cannot be done as the ACS coefficient cannot be partitioned in this way.

The Secretariat indicated that although say 30% of the benefits was seen in the 1st five years, it demonstrated front-loading of the benefits. Another member followed this with evidence from the Hong Kong study which showed a shift in the survival curve after an intervention; this shift did not take long to occur. As such, if there is a sudden drop in exposure, some long-term benefits should be seen rapidly (within a year). The Secretariat then suggested that the phrase "of the order of" be used in indicating how much benefit is likely to be seen in the years following a reduction in air pollution.

One member noted that this issue goes beyond calculations:

• Was the sub-group correct in focusing on the earlier rather than the later measurement period?
• Are there any implications regarding what is said about uncertainty?
• Check wording on latencies for lung cancer (a high proportion of the effect on lung cancer is not at all likely in the first 5 years not just less likely as in line 47).

2. Uncertainty. The following arose in the discussion:

• Improve the text (pg 46 lines 43-47) describing Figure 3.5.
• Explain how Figure 3.5 has been derived and why
• Some queried whether the mode or median should be used. The results of the elicitation exercise showed a significant amount of opinion in the central estimate being > 3% and as such it is imprudent to ignore this; it is better to use the median in selecting the central estimate and the percentiles for describing the uncertainty interval.
• Leave current text on this topic in the main report
• Change the order of Figures 3.5 and 3.6 on pg 47
• Figure 3.5 expresses coefficients as %; Figure 3.6 as relative risks - consider making consistent.
• Place the individual responses from the exercise in an annex to demonstrate the disparity of values between members.

A member indicated their preference for a 75% plausibility interval and that it should be used as the headline result. Although the Chairman of the subgroup was content with this suggestion in describing the plausibility interval, he was wary about suggesting that it be used for sensitivity analyses.

19. All changes will have implications to the Executive Summary as well as the text in the final chapter.

ITEM 6. AOB

QUARK II Morbidity

20. Members were informed of a meeting between the Chairman of COMEAP, Prof. Steve Holgate (Chairman of the working group) and the Secretariat on the 29th August. Apologies for this meeting were received from Mr Fintan Hurley (Chairman of the QUARK II subgroup). It was considered a useful meeting and raised questions which would need to be considered by the morbidity working group, such as:

• Defining the problem of long term exposure to air pollution on various indices of morbidity
• Defining long term exposure
• Defining morbidity
• The evidence available and consideration given to ancillary evidence and mechanistic work
• The evidence available for the different air pollutants.

21. The Secretariat indicated that a paper would be written to describe the philosophy behind the morbidity work and this would be circulated to the working group prior to their first meeting, proposed for December 2006 (date still to be confirmed).
ACTION: SECRETARIAT

22. It was agreed that mechanisms were important in interpreting long-term effects of the development of disease over a long period. Mechanistic evidence would also enable judgement to be made on whether the epidemiology indicated long-term effects.

23. It was accepted that the report would cover outcome measures that were unlikely to be related to daily excursions, as was mentioned by one member and it was also confirmed that the problem of baseline rates would need to be discussed.

24. Members were reminded that the coefficient for mortality and Myocardial Infarction could be scaled to give an approximate estimate of morbidity.

EPAQS

25. It was explained to the Committee that the majority of work on metals being undertaken by EPAQS was near completion. In light of this and the decline in further work pertinent to EPAQS being provided to them by Defra, it had been decided that EPAQS and COMEAP would merge. It was noted that not all members would be transferred, although at this time no names in this regard could be provided. Members were informed that the transferring EPAQS members would, in their own right stand as a sub-group, being used to answer questions regarding the Air Quality Strategy. However, Members of this sub-group would be full Members of COMEAP in their own right and any decisions made by this sub-group would have to be finalised through the main COMEAP committee, as is the case with all sub-groups of COMEAP.

26. It was noted that the EPAQS sub-group would be chaired by Professor Stephen Holgate. It was also made clear that the report emanating from the external review of EPAQS would be made available on the Defra website once the press release on the merger had been made public.

27. It was acknowledged that there was a need to develop thoughts regarding the role of the new sub-group and there would be an horizon scanning process where ideas could be floated. In the past, EPAQS had shown a good approach to risk assessment, which it was agreed, would be prudent to harness. It was suggested that work could be undertaken on organic compounds, which could be produced in a series of reports.

28. It was confirmed that the first day of appointment of previous members of EPAQS would be noted as being their start of appointment on COMEAP.

WHO Children's sub-group

29. It was confirmed that letters of invitation to proposed members of this sub-group had been sent and that the HPA had provided funding for running the group, which would meet a couple of times in order to produce a short report which would: highlight any areas which the WHO report had not considered, discuss implications to the UK of the WHO report's findings and also highlight papers which could feed into the work which had been published since the publication of the WHO work.

Swimming pools and asthma

30. Members were made aware that the Secretariat had asked certain Members of the Committee to provide advice on a paper looking at swimming pools and the incidence of asthma emanating from Belgium (Nickmilder and Bernard, 2006). These Members' comments had been helpful in understanding the importance of this work in light of its contribution to the literature in this subject area. The Committee were informed that, in light of the comments and of the subject area, a discussion paper would be provided at the next meeting.
ACTION: SECRETARIAT

31. Members were reminded that this subject area required careful handling. Naturally this topic could easily be sensationalised by non-scientists through incorrect interpretation of scientific material. It was imperative that incorrect media headlines did not emanate from the Committee's discussion of this topic. It would therefore be incumbent upon the Committee to be able to clearly define asthma and its effects and to show that although chlorine and its byproducts are well known irritant gases, the plausibility that inhalation of the relevant gas would turn someone into an asthmatic needed to be weighed up carefully. At the next meeting of COMEAP, the Committee will be asked to ascertain what the studies imply.

32. One Member expanded on this, highlighting that there were difficulties when linking early life exposure to inception and induction of a disease, which in this scenario would be further complicated by environmental aspects such as humidity.

COMEAP website

33. Members were informed that COMEAP would be getting a new website in light of the Secretariat move to the HPA. The website would be devoid of logos, so highlighting Members' independence. Information from the old website would be transferred to the new one.

34. It was requested that papers, prior to meetings be placed on a password protected part of the site. It was agreed that such an option would be looked into.
ACTION: SECRETARIAT

35. Members were told that a link to the new website would be provided on the Department of Health's website.

36. Members would be kept abreast of progress and of the new website address, once confirmed.
ACTION: SECRETARIAT

ITEM 7. DATE OF NEXT MEETING

37. 23rd February 2007 at Department of Health - Skipton House, Elephant and Castle, London.

Secretariat
November 2006

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