Present:

Chairman: Professor Jon Ayres

Members:
Dr Ben Armstrong
Professor Roy Harrison
Dr Timothy King
Professor Duncan Laxen
Professor Philip Poole-Wilson
Professor Vicki Stone
Professor David Strachan
Professor Dafydd Walters

Secretariat:
Dr Robert Maynard (Medical)
Dr Heather Walton (Scientific)

Assessors: Ms Jackie Maud (Environment Agency)

In attendance:
Professor Ross Anderson
Miss Julia Cumberlidge (Minutes)
Dr Janet Dixon (Defra - Item 5)
Mr Richard Moran (HPA - Item 5)
Professor Virginia Murray (HPA - Item 5)
Mr Jaume Targa (NetCen - Item 5)

ITEM 1. APOLOGIES FOR ABSENCE AND ANNOUNCEMENTS

1. Apologies for absence had been received from: Professor Stephen Holgate, Professor Dick Derwent, Mr Fintan Hurley, Dr Nigel McMahon (NI), Dr Louise Newport (DH), Miss Inga Mills (HPA - Secretariat), Mrs Isabella Myers (HPA - Secretariat), Dr Martin Williams (Defra), Mr Tim Williamson (Defra), and Dr Ronnie Alexander (Wales).

2. The Chairman welcomed Professor Virginia Murray and Mr Richard Moran from the Health Protection Agency and Mr Jaume Targa from netcen who were attending for Item 5 on the Buncefield fire. He also welcomed Dr Janet Dixon from Defra, also attending for item 5 on the Buncefield fire and Item 7 on changes to the PM10 and PM2.5 monitoring systems. It was also noted that she was covering for the new Defra assessor, Mr Tim Williamson.

3. The Chairman went on to welcome Professor Roy Harrison to the meeting. He reminded Members that Professor Harrison had been a past member of COMEAP who had recently been co-opted back on to the Committee after a few years absence.

4. It was noted that Dr Martin Meadows, the Defra assessor had moved on from his air quality job at Defra to work on waste strategy. He had been replaced by Mr Tim Williamson who unfortunately was not able to attend the present meeting.

5. The Chairman informed the Committee that Dr Louise Newport had recently been appointed to the new policy post on air pollution at the Department of Health. He explained that Dr Newport would be the link between the Secretariat at the Health Protection Agency and the Department of Health. Unfortunately, due to having a previous commitment Dr Newport was unable to attend the present meeting but it was noted that she would be attending all future meetings.

6. Members were informed that Professor David Phillips had replaced Professor Peter Blain as Chairman of the COC. Professor Philips would, therefore, replace Professor Blain as an ex officio member of COMEAP.

7. Finally, the Chairman noted that Dr Maynard' s secretary, Mrs Vilma Lecky would be retiring from the Department of Health on 7th July. Dr Maynard commented that his new personal assistant, Ms Anne Marchant, would be starting to work with him from 10th July.

8. On an administrative note, Members were reminded to declare any interests they might have in each item at the start of the discussion of that item and were also reminded to fill in the expenses claim forms provided.

ITEM 2. MINUTES OF THE MEETING HELD ON 24th FEBRUARY 2006. COMEAP/MIN/2006/1

9. Due to unforeseen circumstances, the Secretariat reported that the full minutes of the last meeting were not currently available. However, it was pointed out that the short note of the meeting (agreed with the Chairman and subsequently placed on the COMEAP website) had been circulated to remind Members of the key points raised at the meeting. It was agreed that the full minutes would be circulated for comments in writing at a later date.

[ACTION: Secretariat]

ITEM 3. MATTERS ARISING

3.1 Annual Air Pollution Research Meeting

10. The Secretariat commented that it had concluded that it would not be practical to hold the Annual Air Pollution Research meeting this year (only very expensive accommodation was available) but went on to say that it was pressing ahead with organising a meeting probably to be held in April 2007. A Member commented that in the past, this annual research meeting had overlapped directly or partially with the Annual Conference meeting held by the Health Effects Institute (HEI), and asked that since HEI had already decided on the date for their 2007 meeting, that that date be avoided if at all possible.

[ACTION: Secretariat]

11. Members asked whether the meeting would continue to be held in Leicester, since the Institute for Environment and Health (IEH), which had hosted all previous meetings, had now moved to new premises at Cranfield. The Secretariat replied that cost was likely to be the deciding factor. The meeting could probably continue to be held in Leicester, although there was no reason why this should absolutely be the case. Members were welcome to suggest alternative venues.

[ACTION: Members]

3.2 Report on Air Pollution and Cardiovascular Disease

12. The Secretariat noted that the Committee's report on Cardiovascular Disease and Air Pollution had been published earlier in the year and had been well received by the scientific community. There had been very little criticism of the report, and it had been drawn to the attention of the cardiovascular research community who had received it well. It was felt that once the report started to be referenced in reviews and journal articles discussing cardiovascular disease, it would have become a well-established addition to the literature on air pollution and cardiovascular disease.

3.3 Papers by George Knox

13. The Secretariat commented that it had written to Professor Paul Elliott at SAHSU regarding the paper by Knox which had been discussed at the last meeting, but to-date, no reply had been received.

3.4 Effects of Air Pollution on Child Health

14. The Secretariat had held a meeting with Professor Walters (who had agreed to chair a small group looking at this topic) to discuss how they might tackle the issue of the effects of air pollution on children's health. It had been agreed that, in the first instance, a small group would be convened and as a starting point would read the recently published WHO review in order to see if anything had been missed from this document. Implications for the UK would be focused upon. The Secretariat and Professor Walters were currently drawing up a list of names to approach regarding membership of a COMEAP subgroup.

ITEM 4. REPORT ON PROCESS AND PROGRESS SO FAR WITH QUARK 2

15. The Secretariat informed Members that a meeting had been held on 23rd May 2006 to discuss the latest draft of the full report on long-term exposure to air pollution and mortality. It had been agreed to publish this section of the report separately rather than wait for the work on morbidity. At that meeting, some rearrangements of the structure of the report had been suggested and it was noted that the Secretariat was now progressing well with putting these in place. However, this had meant that it was not possible to bring the draft report to the current COMEAP meeting. It was noted that after sending the restructured report to the subgroup Chairman for agreement, it would be circulated to the subgroup for further comments in writing before bringing it to COMEAP for consideration in October. The Secretariat commented that the document was very detailed and had covered issues in far more depth than, for example, had the EPA or WHO. It was noted that the key thinking and conclusions were now fully developed and included the following:

• It was noted that the uncertainty range would use the results from the uncertainty elicitation exercise. This suggested an uncertainty range of 2 to 9% around the coefficient of 6% per 10 µg/m3 PM2.5.
• Numerical estimates of expected changes in mortality rates due to changes in pollution since the 1970s would be given and a more qualitative discussion would be provided of expected changes in mortality rates due to changes in pollution since the 1950s.

16. The Secretariat went on to say that the issue of long-term exposure to air pollution and morbidity was more difficult to address and that a strategy meeting on how to approach the evaluation of the evidence on long-term exposure and morbidity had been arranged for the 11th of July. This was intended to be a scoping meeting between the Secretariat and the Chairmen of QUARK 2, COMEAP and the morbidity subgroup.

ITEM 5. BUNCEFIELD FIRE. COMEAP/2006/03 AND FULL REPORT

17. Members' attention was drawn to COMEAP/2006/03 and the report entitled "Initial Review of Air Quality Aspects of the Buncefield Oil Depot Explosion" /www.defra.gov.uk/environment/airquality/buncefield/index.htm). This report, prepared by netcen, provided a detailed account of the concentrations of pollutants recorded in London whilst the event was taking place. Members' attention was drawn to the appendices of the report; particular attention was drawn to appendix H which set out the role and activities of the Health Protection Agency during the incident, gave further data on concentrations of pollutants and provided the results of modelling work.

18. Members were asked:

• to examine the netcen report and to focus on data relating to concentrations of pollutants;
• to consider these data in relation to possible exposure;
• to comment on the possible effects on health of exposure to such concentrations as were recorded.

19. A summary of the incident and how it was handled was presented by Professor Virginia Murray ( Slides from this presentation can be obtained on request from Professor Murray). Professor Murray also asked Members to advise on

• post-incident epidemiological studies;
• the need for electronic recording at Accident & Emergency departments to expedite such studies;
• what might have been the implications for health had more extensive ground level pollution occurred.

20. Members warmly welcomed Professor Murray's presentation and congratulated her and others at the HPA on their response to this exceptional incident.

21. In response to a question from Members, Professor Murray explained that there would be a further report on potential health effects from the fire. This would be published by the Chemical Hazards and Poisons division of the Health Protection Agency probably around the end of July. A larger study of the incident is due to be published by the Health and Safety Executive in the Autumn.

Pollutants from the fire

22. Members noted the minimal effects of the fire on monitored concentrations of major air pollutants and concluded that significant effects on health due to exposure to the air pollutants currently monitored were unlikely to have occurred. In reaching this view, Members deliberately excluded consideration of possible effects on those involved with dealing with the fire: this is a problem for experts in occupational health.

23. The Committee asked if particular chemical constituents of PM had been measured. It was confirmed that monitoring had not looked at metals specifically. The only specific constituents measured were dioxins, polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs). However, filters from the particle monitors were available for research study in the usual way. Members pointed out that the likely low chlorine content of the fuel meant that dioxin formation was not likely to have been significant. Thus, effects of such compounds on health should not be anticipated.

24. Members pointed out that the netcen report did not mention the sulphur content of the fuels - this may have been significant. (It was subsequently confirmed that no major sulphur dioxide signals had been seen (these would have been picked up by the usual bulletin system). Netcen's initial scoping of major expected emissions showed PM to be the main issue. )

25. Perfluoryloctylsulphonate used in fire fighting foam was identified as a potential issue. It is a carcinogen and is being phased out. The Committee was informed that there was no monitoring of this in the air but that it was expected to have a low volatility. It was therefore not expected to be an air pollution issue. It had been monitored in soil and grass but had not been found. It was being monitored in boreholes and the results were being processed.

Monitoring health effects from the fire

26. Members considered that, in the light of no significant changes in ground level concentrations of air pollutants, it was unlikely that epidemiological studies would detect effects of air pollutants released by the fire on health.

27. Members noted that any possible increases in attendances at Accident & Emergency departments should be examined in the light of normal day-to-day variations in these data, comparing data to control time periods and in control areas. It needed to be borne in mind that other factors might, by chance, be influencing outcomes in the affected area e.g. if there happened to be a viral epidemic. Outcomes other than the most obvious ones should be considered - for example, sudden cardiac death might be affected by air pollution. However, the difficulty of separating this from the effects of stress was noted.

Suggestions for future incidents

28. The Chairman expressed some surprise that he had not been consulted earlier on in the incident. Members considered that it would be helpful to be kept informed to help them to deal with any enquiries from the media. It was clarified that it was not COMEAP's role to take part in the actual management of an incident, but rather to advise on the health effects of specified levels of air pollution. COMEAP could help in providing advice that could be used in future incidents.

29. Members considered that further work could be done to optimise the equipment available for air pollutant sampling and the sampling protocols.

30. There was discussion of what would have happened if the meteorological conditions had been different. It should be possible to model this and also to model whether extinguishing such fires was always a good strategy. The Committee was informed that the Met Office and netcen were indeed modelling these scenarios and were writing up a report. The Committee asked whether these would be taken through to modelling the expected health effects in worst case scenarios? This could help in planning the most effective advice in these potential situations.

31. Other issues relating to planning future advice included consideration of whether there was a level of particulate air pollution which would lead to advice to evacuate people's homes rather than advice for people to stay indoors. The Secretariat was asked to develop a way forward for considering this further. It was also noted that fine particles could penetrate indoors and it was recommended that thought be given to providing advice on how to reduce levels of ingress should outside particle concentrations be very high.

[ACTION: SECRETARIAT]

32. Members noted the possibility of estimating and predicting health impacts from similar incidents by risk assessment - modelling expected health effects by combining measured or predicted ground level air pollution with published estimates of dose-response relationships. Compared to epidemiology this had the advantage of being faster and was not limited by considerations of low statistical power. It rested however on an assumption that the published dose-response relationships were relevant to the pollution in question. This might be questionable if the pollutants released had toxic properties unlike typical urban air pollution. (In the case of Buncefield, the main pollutants released were typical urban air pollutants.) It would also need to be assumed that the days were typical whereas the days of an incident might be atypical e.g. if people stayed indoors more than usual. In addition, for particles, a change in the 24-hour average would need to be predicted - current time-series results were not informative about the effects of a transient high concentration.

33. Such use of time-series evidence would be crucially dependent on predicting weather conditions and thus air pollution levels. It was therefore important that Met Office advice on weather conditions could be transmitted rapidly to all places at which it was needed.

34. It was noted that it was possible for health effects to be predicted using time-series evidence that would not be detectable using an episode study. It was unlikely that an epidemiological study of one episode would be sufficiently powerful to detect adverse effects if these were to increase disease risks by only a few percent. The only value of such a study would be to provide reassurance that the episode had not caused a large percentage increase in disease risks. Professor Anderson's second report on the 1991 air pollution episode compared the effect of the transient increases in air pollution in Birmingham, Manchester and London. In London, health effects were detected in this episode analysis but they were not in Birmingham or Manchester where concentrations were lower. This might help give an idea of the limit of detectability. It was agreed that this report would be circulated around COMEAP.

[ACTION: SECRETARIAT]

35. Members considered the case for electronic recording of attendances at Accident and Emergency departments. It was felt that this case would have to be considered very carefully on its own merits, taking into account other issues in addition to the investigation of chemical incidents. Any satisfactory computerised system would have to be as comprehensive as the current hard copy records and this had not always been found to be the case in the past. Overall, Members did not wish to make specific recommendations on this point but accepted that good quality computerised record keeping might help.

36. Members noted that rapid exploration of possible effects on health was needed during an incident such as the Buncefield Fire. It was argued that these should be seen as part of the emergency public health response to an incident and not as research studies requiring ethical approval. However, members also suggested that consideration should be given to the potential adverse effects of undertaking a survey on health effects when the pollutant levels were known to be no higher than usual. Such a judgement can be made in the light of initial data on pollutant levels.

37. Members also suggested that should, in future, a similar event occur and that effects on health were deemed more likely on the basis of initial levels of pollution, that a clear indication should be obtained from an ethics committee on whether ethical approval would be needed for such a survey. It was the view of the committee that this was not necessary in the context of such an event and indeed might delay investigation to a time when memory and opinions would have changed in those surveyed.

38. It was agreed that the Secretariat would draft a statement based on the Committee's discussions and circulate this for comments from the Committee. It would be made clear which recommendations were general and which were specific to facilities such as those at Buncefield (where burning of the fuel released typical urban air pollutants).

[ACTION: SECRETARIAT]

ITEM 6a. OZONE. CHAPTER 8 HEALTH EFFECTS OF LONG-TERM EXPOSURE TO OZONE COMEAP/2006/04, ANNEX TO COMEAP/2006/04, TABLED PAPER WITH POOLED RESULTS FOR LUNG CANCER AND ASTHMA INCIDENCE FROM THE SEVENTH DAY ADVENTIST STUDY

39. Introducing this item, the Secretariat reminded Members that Chapter 8 of Part 1 of the Ozone Report had not been written when the Committee last saw the Ozone Report. This has now been completed, including incorporation of comments from the ozone subgroup. It was noted that the covering paper (COMEAP/2006/04) set out, for the benefit of Members of the ozone subgroup, changes that had been made since it was last discussed by the subgroup. It was noted that the overall conclusions were also included in COMEAP/2006/04. These included the following:

• For mortality, there was no clear positive association but there were caveats (possible raised cardiorespiratory mortality in summer and limitations in the studies meant that this conclusion should be regarded as a temporary one pending further research).
• For lung cancer, there was inconsistent evidence but overall it was concluded that the evidence pointed in the direction of no effect.
• For asthma incidence, the evidence was uncertain, but it was thought that ozone was unlikely to be playing a major part in increasing new cases of asthma overall.
• The evidence regarding respiratory symptoms was mixed.
• With regard to lung function, associations predominantly indicated a decline in lung function. Association with reductions in lung function growth were seen in some studies but not others. It was noted that this effect might be reversible with age or over a winter period. The results for lung function were thought to be less clear cut than might have been expected.

40. The Secretariat went on to say that, at the subgroup meeting held last June, Members had expressed a wish to think further about the evidence on ozone and lung function growth. No further comments were received after the meeting. Therefore, some of the key original papers had been attached as an addendum to COMEAP/2006/04 to assist Members in thinking about this issue more deeply. The Secretariat commented that, given the clear links between ozone and reduced lung function in chamber studies and panel studies on daily fluctuations, it was somewhat surprising that some studies found only equivocal evidence of an effect on lung function growth and, in the Southern California Children's Health study, other pollutants seemed to be more important. Members' comments on Chapter 8 were invited.

Mortality

41. There was discussion of the evidence for an effect of long-term exposure to ozone and mortality. Some Members considered that the current conclusions needed to be toned down as there was not much evidence for an effect of long-term exposure. Others were more cautious, pointing out that a positive association between ozone and cardiorespiratory mortality had been shown in the summer and there was supporting evidence from animal experiments. In addition, the ACS study had not been specifically designed to examine the effects of ozone. Possible masking of the effect of ozone due to negative correlation with other pollutants was discussed but it was pointed out that the HEI reanalysis reported that adjustment for sulphate did not affect the ozone association.

42. The discussion moved on to consider why it might be that there was clear evidence for an effect of short-term exposure to ozone on mortality but that this did not appear to be clearly picked up in the cohort studies. This was in contrast to the results for particles. One idea proposed to explain this was that the main effect of particles appeared to be on cardiovascular mortality. This tended to affect people at younger ages than for respiratory mortality, and therefore led to greater losses of life-expectancy that could be more easily picked up in the cohort studies. If ozone, on the other hand, had a greater effect on respiratory mortality, then the loss of life-expectancy would probably be smaller and harder to pick up in the cohort studies. It was noted that the HEI reanalysis of the ACS study had not reported separate results for ozone and cardiovascular or respiratory mortality as it had for particles. However, for hospital admissions, short-term exposure to ozone had the largest and clearest association with respiratory admissions in the elderly but no association with cardiovascular admissions.

43. It was agreed that this discussion of possible different causal pathways for particles and ozone should be reflected in the report. It was also agreed to delete the text after 'However' in paragraph 8.98.

44. It was suggested that the discussion of possible increased personal exposure in summer due to windows being open in paragraph 8.19 should be expanded to reflect the fact that this might not apply in places where the use of air conditioning was widespread.

Lung cancer

45. Members' attention was drawn to the tabled paper which provided pooled results from the Seventh Day Adventist's study for men and women together. There were no comments on the conclusions for lung cancer.

Asthma incidence

46. It was agreed to combine the asthma incidence section with the respiratory symptoms section and to refer to the forthcoming report on air pollution and asthma for a more complete discussion of the issues.

Respiratory symptoms

47. There was discussion of whether some of the mixed evidence on ozone and respiratory symptoms was due to the disparity in the range of ozone concentrations in the different studies. The Secretariat explained that the second part of the ozone report would look in more detail at whether the results from studies with different ranges of concentrations provided any indication of a threshold. There were some complicated aspects to this. A meta-analysis would actually weight indirectly for the range of ozone concentrations since it weights for standard error and this depends on the range. The standard error of a slope will be larger if the concentration range is small and vice versa.

48. Caution in interpretation was suggested since some studies used central city monitors at which ozone concentrations were suppressed by nitric oxide emissions. This might not represent ozone exposure across the whole city since nitric oxide emissions in the suburbs were likely to be lower and ozone levels higher.

49. It was suggested that the respiratory symptoms section was subdivided into those studies comparing different cities and those comparing symptoms within cities using, for example, 1km grid squares. Negative correlations with other pollutants were more likely to be an issue in the latter type of study.

Lung function

50. It was agreed that the term 'decline in lung function' would be reserved for studies in which lung function was examined sequentially over time. For studies where lung function was measured in different areas at only one time point, a phrase along the lines of 'Children living and measured in high ozone areas tended to have lower lung function' would be preferable. This applied to paragraphs 8.92 and 8.102.

51. It was agreed that, in Table 8.19, the table entries for Dockery et al (1989) reporting 'little evidence for association' should be shown in black rather than red (positive association) or blue (negative association).

52. There was discussion of the fact that, ideally, lung function growth should be measured by taking children from the different areas to an area with no ozone and only measuring lung function after they had had time to acclimatise in the area with no ozone. It was agreed that paragraph 8.102 was a reasonable summary of the evidence but it was suggested that this point was added.

53. It was agreed that it would be emphasised that the conclusions to Chapter 8 related to the epidemiological evidence only. The animal studies were another strand of evidence - these would be discussed in Chapter 9.

ITEM 6B. OZONE. EXECUTIVE SUMMARY. COMEAP/2006/05, ADDENDUM ON COMPARISON OF OLD AND NEW VERSIONS OF TABLE OF META-ANALYSIS RESULTS

54. The Secretariat explained that this was the first draft of the Executive Summary of Part 1 of the report to be seen by either the subgroup or COMEAP but that many parts had been extracted directly from the report, in particular, the overall conclusions from Chapter 9. These had been revised after the COMEAP meeting in November 2004 at which they were discussed and circulated for further written comment. No further comments had been received.

55. The Secretariat went on to describe some of the changes that had occurred since the last COMEAP discussion. With regard to meta-analysis results, it was noted that extensive work had been done checking the consistency of inclusion or exclusion of studies for meta-analysis across different parts of the report. Since these were done at different times over an extended time period some inconsistencies were discovered. To resolve these inconsistencies, it was decided to adhere strictly to the specified ICD grouping for the outcome.

56. Several of the meta-analyses were redone to take this into account, and this resulted in some combinations of outcome and averaging time having too few studies for meta-analysis or in the meta-analysis results becoming non-significant. For other combinations of outcome and averaging time, there was no change in direction or statistical significance of the outcome. It was noted that details of these changes were set out in COMEAP/2006/05 and that the key question for the Committee was whether it was content to leave the conclusions as they were previously or whether to modify the conclusions.

57. The Committee agreed with the approach to ICD code selection and were content to leave the previous conclusions unchanged. The conclusions were drawn not only from the meta-analysis results but also from the tables and figures which included studies with less precisely defined groups of ICD codes. It was suggested that reference could be made to the air pollution and cardiovascular disease report, in which the meta-analysis was more inclusive in terms of including studies using ICD code groupings which did not fully match the relevant criteria. This would make the point that the stricter the criteria for ICD code groupings the lower the power of the meta-analysis as more studies were excluded.

58. The Secretariat commented that the causality of the associations with long-term exposure to ozone had not so far been discussed. Text on animal studies of long-term exposure to ozone for Chapter 9 (causality) had yet to be written. A short paragraph on long-term exposure for the overall conclusions had been proposed for discussion. The Committee considered that the long-term exposure conclusions should be further subdivided to include separate conclusions on mortality and lung cancer as well as respiratory symptoms and lung function.

59. Some proposals for further work had been extracted from various parts of the report, and Members were invited to submit any additional suggestions. It was suggested that a recommendation for further work into variation in individual responsiveness including adaptation should be added.

60. The Secretariat agreed to incorporate the changes to Chapter 8 and the Executive Summary requested by the Committee. As for the other chapters of the ozone report it was agreed that these did not need to be seen by the full Committee again - final editing would be left to the Chairman and the subgroup. The Secretariat pointed out that there were a number of actions on the report which remained outstanding, the Secretariat would persist with these with the intention of producing a final draft by the end of the year.

[ACTION: SECRETARIAT]

ITEM 7. CHANGES TO PM10 and PM2.5 MONITORING METHODS - IMPLICATIONS FOR EPIDEMIOLOGICAL STUDIES. COMEAP/2006/06

61. Members were reminded that the standard monitoring method in Defra's network, the TEOM, missed some particle mass due to loss of volatiles from the heated filters. A correction factor of 1.3 had been used to compensate for this and make the TEOM results equivalent to those found with the gravimetric method.

62. It was commented that the correction factor of 1.3 had always been known to be approximate. Defra had funded a detailed study* to investigate the robustness of this factor using equivalence criteria set by the Commission. The TEOMs did not meet these equivalence criteria even with a correction factor. Therefore, Defra had no choice but to adjust their monitoring equipment so that it did meet the equivalence criteria. Members were told that it was possible to achieve this by modifying the TEOMs to correct for the loss of semi-volatiles. (The modified equipment is known as a TEOM retrofitted with FDMS - FDMS stands for Filter Dynamics Measurement System).
*www.airquality.co.uk/archive/reports/cat05/0606130952_UKPMEquivalence.pdf

63. It was pointed out that a change to the particle monitoring methods clearly had implications for epidemiological studies, particularly any that spanned the period in which the monitoring method was changing. The Secretariat was keen that epidemiologists in the air pollution field were made aware of this forthcoming change. It was noted that the report included equations that allow conversion of TEOM data to FDMS-TEOM data and vice versa which it was thought would help in ensuring consistency.

64. The Committee was invited to comment on any points relating to communicating this change more widely and on any help that Defra could give in terms of managing the transition to the new method.

65. In response to a query from the Committee, it was explained that the air quality archive (www.airquality.co.uk) would provide 3 sets of data. The main set would be the total result (FDMS/TEOM base plus FDMS/TEOM volatiles). However, the FDMS/TEOM base and FDMS/TEOM volatiles would also be given separately.

66. It was felt that providing a conversion factor was available, epidemiologists would have what was needed. (There were equations to convert from one measurement method to the other available in the report published by Defra.)

67. It was suggested that it would be helpful if Defra could change the equipment close to the beginning of a calendar year so that data were available for a whole calendar year with the new method.

[ACTION: DEFRA].

ITEM 8. ANY OTHER BUSINESS

68. There was no other business.

ITEM 9. DATE OF NEXT MEETING

69. The following date was noted:

13th October 2006.

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