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Committee on the medical effects of air pollutantsMinutes of the meeting held on Friday 24th February 2006 in Room 149, Department of Health, Richmond House, 79 Whitehall, London SW1A
ITEM 1. OPENING REMARKS, APOLOGIES FOR ABSENCE AND ANNOUNCEMENTS 1. Apologies for absence were received from Prof. V Stone, Mr F Hurley, Prof. R Harrison, Dr M Williams, Prof. P Burney, Mr M Meadows, Prof. S Holgate, Mr R Alexander (Welsh Assembly), Mr N McMahon (Northern Ireland), Dr H Walker (DH). 2. The Chairman welcomed Dr Timothy King, who had recently been appointed as the lay member on the Committee. Mr John Stedman and Mr R Atkinson who were attending due to their involvement in Quark II and Ms Jackie Maud from the Environment Agency, attending as an observer, were also welcomed. 3. Members were informed of the following changes to the membership of COMEAP: Professor Roy Harrison had been co-opted onto COMEAP; Professor Tony Frew and Professor Virginia Murray had both come to the end of their terms, although Professor Frew would continue as a member of the Asthma sub-group; Mr Fintan Hurley had come to the end of his term on COMEAP, but would continue to attend meetings due to his role as chairman of the QUARK II sub-group; Dr Robin Fielder would no longer be attending meetings as an observer from the HPA as the Secretariat had now transferred to this organisation. In the light of this change, Dr Hilary Walker would attend COMEAP meetings as an observer from the Department of Health. 4. The Chairman reminded Members to declare any interests they may have. 5. The Chairman reminded Members to submit their expenses claim forms.
6. The Chairman took Members through the Minutes of the last meeting page by page. Members agreed that the minutes were an accurate record of the meeting. ITEM 3. MATTERS ARISING Annual Air Pollution Meeting 9. Members were informed that the Institute of Environment and Health,
now based at Cranfield University would continue to organise this annual
meeting, although a date for this year’s meeting had yet to be confirmed.
The Secretariat would keep Members updated on progress. The Chairman reminded
Members that they were expected to attend this meeting. 10. The Chairman thanked members for all the hard work that had gone into the production of this excellent report, which would be launched on the 2nd of March 2006. Members were informed that they would be provided with a hard copy of the report. The Chairman also reminded members that the report would be available on the COMEAP website. Ozone Report ITEM 4. REPORT ON PROCESS AND PROGRESS SO FAR FROM QUARK II 12. The Chairman informed Members that a substantial amount of work had taken place in preparing the first part of this report which addressed long-term exposure to air pollutants and mortality. The Chairman informed Members that the effects of long-term exposure dominated cost benefit analysis and that this report would form a basis for such work. In summarising, the Chairman updated Members, informing them that a preliminary statement (tabled) which gave a coefficient of 6% per 10µg/m3 of PM2.5 (a 6-fold increase from that provided in COMEAP’s 2001 quantification report) had been placed on the COMEAP website in mid-January 2006 and that a supporting report of approximately 40-50 pages was nearing completion. The Chairman handed over to the Secretariat to provide a more detailed update. 13. The Secretariat outlined the process used by Members to enable them to provide an interim statement, a co-efficient for Defra to feed into their review of the Air Quality Strategy and to compile a short report on quantifying the effects of exposure to the long-term effects of air pollutants on mortality. The Secretariat explained that this process included members of the sub-group undertaking some original work regarding the statistical aspects of interpreting results from the leading cohort studies on long-term exposure to air pollutants (especially fine particles) and effects on health. In particular, original work regarding spatial autocorrelation and confounding (which takes into account the uncertainty in the estimate) was particularly noted. Members of the sub-group had indicated that there were other grounds for uncertainty and this prompted the Secretariat to undertake an exercise involving the elicitation of members’ views on uncertainty, although the results of this have yet to be discussed. 14. Sub-group members had addressed lags and latency to ascertain the timing of benefits following a reduction in pollutant levels, a particularly important point for policy decision making. It was explained to Members that the use of life table analysis was employed for this, a system run at the Institute of Occupational Medicine. 15. Members were informed that the QUARK II sub-group were still to decide
whether the report on mortality would be published separately or as part
of a larger report incorporating the results from the analysis of the
effects of air pollutants on morbidity. A formal decision would be taken
by the sub-group on the publication of the work on mortality. 17. The Chairman then asked Members if they had any questions or comments regarding the work completed by the sub-group so far. 18. One member questioned whether uncertainty relating to exposure had
been discussed. It was explained that this area had been dealt with in
the context of modelling work being carried out for Defra. The Secretariat
suggested that the QUARK II sub-group might have a discussion on the importance
of exposure measurements. Action: Secretariat / QUARK II Sub-group 19. It was noted that the statement discussed cardio-respiratory mortality, whereas during work on the cardiovascular disease and air pollution report, it had been decided that it was best to separate these deaths into cardiovascular and respiratory deaths. The Chairman agreed that further work should be done on this point and another member thought it would be wise to make sure that this was addressed in the work carried out on morbidity. Action: Secretariat/ QUARK II Sub-group 20. One member expressed concern about the selection of PM2.5 as the metric used in this quantification process. It was explained that the focus and use of the cohort studies from the USA have driven this. However, this was challenged in light of the fact that PM10 and TSP measurements were available throughout the whole study which was not the case with PM2.5. Resolution of this point was made by explaining that the metric used in the major cohort studies from the USA was PM2.5 and that a decision based on this metric was given to Defra in the absence of other equivalently good papers using any other metric. The full report on mortality would discuss other metrics. 21. Another member noted that the statement did not marry the estimate
given in the report, with information on exposure in the UK. It was explained
that when this was done it would involve adding up the impacts in areas
with different concentrations and different population sizes. This highlighted
a difficult area, based on the fact that the personal exposure levels
of the entire population of the UK were unknown. Studies of personal exposure
levels where personal monitors were used tended to be too small for quantification
purposes and it was noted that all the large, substantive epidemiological
studies, were ecological. The problem was further elucidated by the point
that even when instilling a known mass of particles into rat lung, reactions
between rats varied enormously. ITEM 5: QUARK II WORKPLAN COMEAP/2006/1 22. Members’ attention was drawn to COMEAP paper 2006/01, which was presented to initiate discussion on long-term exposure to air pollutants and morbidity. Members were informed that this was the next phase of the QUARK II project and one which had not as yet been discussed by the sub-group. 23. The Secretariat passed on the thoughts on this paper which had been provided to the Secretariat by the Chairman of the QUARK II sub-group Mr Fintan Hurley. His comments related mainly to the process behind how long-term exposure to air pollutants was to be defined and how the sub-group would define outcome measures which are unlikely to be related to daily excursions in concentrations of pollutants. Mr Hurley thought that the paper overcomplicated the problem and that the problem could be solved by looking at studies which related to annual average concentrations as an index of long-term exposure and incidence, rather than prevalence and from this derive a coefficient. 24. The need to decide upon an index of long-term exposure was expressed and it was suggested that concerns regarding peaks vs long-term averages could be approached by asking ‘What will be the impact of a long-term decrease in exposure in Britain including both acute and chronic effects?’ It was confirmed that this would be very straightforward and information to feed into this process was available. 25. One member outlined how important morbidity was in relation to cardiovascular disease. The acute onset of a myocardial infarction leading to heart failure was used as an example of a long-term consequence of a short term exposure. Being aware of this was important for the cost effectiveness of policy decisions. COPD was noted as the antithesis of myocardial infarction/heart failure in that it was rare for a short term exposure or event to lead to the chronic disease. These example situations also highlighted the different methods used in the management, diagnosis, treatment and changes of treatment practices of different diseases and the impact this had on admissions data. Defining changes in respiratory morbidity was more difficult than for cardiovascular morbidity – for example changes in admissions for asthma in childhood can vary for reasons other than underlying morbidity rates e.g. changes in hospital policies. It was noted that these were considerations which would have to be taken into account. 26. Members discussed the practicalities of moving forward with work on morbidity. Some looked at the usefulness of preparing a list of plausible health outcomes and then addressing the literature. Another suggestion was to start from the cost benefit analysis end and establish what effects were likely to drive the results and then analyse the literature to find out what evidence there was for the relevant effects. Others suggested establishing what information is required for policy to reduce risks to health, outside of the remit of QUARK II and then ascertain what information from QUARK II could feed into these policy making decisions. 27. Another member informed the group that by looking at the short term effects in the time-series studies and comparing high exposure and low exposure areas, it would be possible to look at variations, both temporal and spatial, to determine the relative importance of short-term variations with an underlying high pollutant concentration vs short-term variations with an underlying low pollutant concentration. Pollutant concentrations in the areas where time-series studies had been performed would be required. 28. A speculative idea was suggested in that, for some disease outcomes,
there was a reasonably well established ratio between morbidity and mortality.
If, for example, the relationship in the population between deaths from
myocardial infarction and numbers of people with angina was known and
the effect of air pollution on fatal myocardial infarctions was known,
it would be possible to get an indirect indication of the effect of air
pollution on angina. It was noted that this assumed that the effect of
air pollution on cardiovascular deaths acted through an effect on the
incident disease. An effect of air pollution on arrhythmias for example,
might lead directly to death without an intervening effect on morbidity.
It was also noted that this idea was not appropriate for asthma where
asthma deaths were rare but the burden of asthma morbidity was substantial. Action: Secretariat 30. Ken Donaldson informed Members of a paper by Andrew Churg who found ‘normal’ women in Mexico City who had died from trauma presented classical signs of small airway remodelling which could produce COPD. It was agreed that this paper would be sent to the Secretariat. Action: Professor Ken Donaldson 31. Another approach was suggested whereby stakeholders could be asked to provide questions which the committee would then try to answer. It was noted that the biggest impact would be the effect of a policy on life expectancy, rather than the impact on costs to the NHS. Included in this was the shortening of life expectancy and how much people would be willing to pay to prevent this occurring. Publication of QUARK II report Action: Secretariat ITEM 6: HAZARD IDENTIFICATION 34. It was agreed that although this was a good idea in principle, there were potential difficulties with timing and workloads which would need to be addressed.. 35. The Chairman agreed to discuss this with the QUARK II chairman as it was necessary for some pollutant/effect scenarios to be addressed foremost for the QUARK II report. Action: Chairman/Secretariat ITEM 7. COMEAP FORWARD PLAN Asthma and Air Pollution Report COMEAP contribution to CEHAPE COMEAP 2006/02 37. This paper outlined a suggestion that a working group should be formed to develop a response to a DH and HPA request for advice on the effects of air pollutants on child health. 38. It was agreed that the recent WHO report on Children’s Health and Development would be used as a basis on which to base a UK focussed approach. Members were in agreement that a small working group, led by Professor Dafydd Walters, should be formed to carry out this task. It was noted that the WHO report was not a comprehensive report and that much of the work on which it was based was from Eastern Europe where the air pollution would be different from that found in the UK. 39. Members were asked to express interest in the group and were notified that a report would be required by mid-2006. 40. The Secretariat would assist in the setting up of this group. Action: Secretariat Buncefield Fire COMEAP 2006/04 41. Members’ attention was drawn to the paper COMEAP 2006/04, a preliminary note which alerted Members to a request by the Health Protection Agency to comment on the on the air pollution data relating to the fire at the Buncefield fuel depot and possible consequences to health. Members were informed that a paper would be prepared for the June meeting of COMEAP and that Professor Virginia Murray from the HPA, who was involved with front-line management of the incident, would attend.
ITEM 9. ROADSIDE EXPOSURE 44. It was noted that it was important to know the relationships between the different possible exposure metrics. Use of a ‘gold standard’ exposure metric might not be possible but use of a surrogate was acceptable if the relationship with the ‘gold standard’ metric was well validated. 45. Members were informed that further information would be provided following a meeting between Professor Ashmore and Professor Laxen and the Secretariat. 46. It was agreed that 3 months notice of the proposed seminar would be given. It was suggested that the seminar might be run as part of the Annual Air Pollution meeting in the summer. Action: Secretariat/Professor Laxen
COMEAP 2006/03 47. Members were provided with a paper from the COC Secretariat which summarised the COC’s views on other, similar papers by Knox in addition to the 2006 Knox paper, which had been circulated to Members for comment. The Chairman noted that the majority of comments queried how the conclusion had been reached about 1,3-Butadiene and since this conclusion was new, it was necessary to consider the extent to which this was justified by the evidence. In addition, there was discussion of the fact that, although local emission levels did not always correlate with ambient concentrations, there was more likely to be a correlation when considering ground level sources such as roads and railways. It was also noted by Members that there were vast numbers of other published epidemiological studies on childhood cancers which should also be consulted. Members agreed that it was necessary for these papers to be taken to a small group of epidemiologists who are also experts in childhood cancers, to establish whether this is an area that COMEAP should consider. It was agreed that the Secretariat would contact some epidemiologists and childhood cancer specialists about forming a small group on this subject. The Secretariat would then work their findings into the COMEAP workplan for further discussion. Action: Secretariat ITEM 10: AOB EPA grant 48. The Chairman reminded Members about the news of an EPA grant on air pollution which had been circulated. It was suggested that one of the recipients of this grant, Professor John Samet, should be invited to a meeting of COMEAP to discuss what recipient centres are doing with the funding. This idea was well received by Members and it was acknowledged that a list of questions would have to be drawn up to help structure the day. Action: Secretariat Air pollution publications rankings Air Pollution A-Z – Professor D Derwent 50. Members were informed that Professor Dick Derwent was updating his book ‘Air Pollution A-Z’. It was requested that Jackie Maud from the Environment Agency informed the Secretariat when it would be available. Action: Jackie Maud ITEM 11. DATE OF NEXT MEETING Secretariat
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