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COMMITTEE
ON THE MEDICAL EFFECTS OF AIR POLLUTANTS
MINUTES - 19
FEBRUARY 1999
COMEAP/MIN/99/1
Present:
Chairman:
Members:
Professor H R Anderson
Professor J G Ayres
Dr M Burr
Dr A R Gibbs
Lord Harris
Professor R Harrison
Mr J F Hurley
Professor D Purser
Professor R Richards
Professor D Strachan
Professor A E Tattersfield
Dr S Walters
Secretariat:
Dr R L Maynard
Dr H A Walton
Miss J P Cumberlidge
Mr J Crook
Assessors:
Dr T Carter(DETR)
Dr S Coster(DETR)
Dr P C T Harrison(IEH)
In Attendance:
ITEM 1. APOLOGIES FOR ABSENCE
AND ANNOUNCEMENTS
1. Apologies for absence had been received from Professor Burney,
Professor Dayan. Professor Poole-Wilson, Professor Seaton, Dr Gavin, Dr
Williams (DETR), Dr Dixon (SO DOH), Mr McAllister (DHNI) and Mr Morris
(SCIEH).
2. The Chairman welcomed Dr Tim Carter. The Chairman also welcomed Mrs
Paula Fryer from the MRC Institute for Environment and Health (IEH). The
Chairman reported that Dr Chris Tuckett had recently left IEH, and that
Dr Benson would attend until Dr Tuckett's post was filled.
ITEM 2. MINUTES OF THE MEETING HELD ON 16 OCTOBER 1998. COMEAP/MIN/98/3
3. The minutes were agreed as an accurate record of the meeting.
ITEM 3. MATTERS ARISING FROM THE MINUTES
4. There were no matters arising from the minutes.
ITEM 4. REVIEW OF THE NATIONAL AIR QUALITY STRATEGY AND ECONOMIC APPRAISAL
OF THE HEALTH EFFECTS OF AIR POLLUTANTS - KEY QUESTIONS RAISED. COMEAP/99/3
5. Publication of the first review of the UK National Air Quality
Strategy was noted. The review and the reports of the working group on
Economic Appraisal of the Health Effects of Air Pollution and the Interdepartmental
Group on Costs and Benefits (An Economic Appraisal of the National Air
Quality Strategy) had been sent to Members.
6. The Review had raised a
number of questions listed in COMEAP/99/3. These were discussed.
(a) Members agreed that the
lack of appropriate studies made the interpretation of road side concentrations
of air pollutants difficult. It was accepted that whilst a few studies
had been done, none had focused on susceptible groups and that studies
of the effects of occupational exposures were of limited value in predicting
such effects because occupational groups were generally healthier than
the general population. The need for better modelling of exposure, including
that of children, was accepted and the use of Geographical Information
Systems (GIS) was suggested. Members recognised that socio-economic confounding
should be considered in interpreting the results of studies of people
living close to roads. Members also noted that peoples' perceptions of
air pollutants, odour for example, might be an inadequate guide to effects
on health. A major question to be addressed was whether policies to reduce
air pollution would change the problem of exposure between road sides
and background sites. Unless the pattern remained similar, could the coefficients
from studies relating health effects to concentrations of pollutants at
background sites be used to predict health effects at road sides?
(b) It was accepted that transboundary
pollutants such as ozone presented special problems and that cost-benefit
analysis of policies to reduce levels of such pollutants should be done
at a European rather than purely UK level.
(c) The importance of quantification
of the effects of air pollutants was discussed. It was stressed that effects
might be important though difficult to quantify and that qualitative assessment
was also important. Ranking of evidence as to qualitative effects and
appropriate quantification were encouraged.
(d) Members encouraged the
Department to pay attention to the possible effects of long-term exposure
to air pollutants. It was noted that a meeting to discuss this had been
arranged for March 4th, and Members were encouraged to attend.
(e) Members discussed the issue
of quality of life assessment as a part of cost-benefit analysis of policies
designed to reduce exposure to air pollutants. It was agreed that this
was an important but difficult area and that work should focus on:
(i) people with severe cardio-respiratory
disease;
(ii) children;
(iii) the sensitivity of indicators
of quality of life.
Members also pointed out that
the benefits on quality of life measures, such as encouraging exercise,
should also be mentioned.
ITEM 5. AIR POLLUTION RESEARCH. COMEAP/99/1
7. The Secretariat reported
that DH intended to launch a new air pollution research initiative in
1999. Paper COMEAP/99/1 was summarised and attention drawn to the advances
that had been made as a result of earlier research initiatives. Key gaps
were identified including the lack of knowledge of the extent of shortening
of life likely to occur as a results of both day-to-day and long-term
exposure to air pollutants. Discussion of individual topics led to the
following conclusions:
(a)Mechanisms of effects
of particles
8.Members agreed that more
work was urgently needed in this area. It was urged that studies should
focus on the fine and ultrafine fractions of the ambient aerosol and on
effects on sensitive individuals. It was also agreed that the role of
metals as components of particles needed further study and the use of
animal models was suggested.
(b)Further analysis of data
generated by time-series studies
9. The case for further analysis
of data already available was discussed. It was agreed that personal exposure
should be better characterised as should the physico-chemical characteristics
of the particles to which people are exposed. The need to study the differences
in results produced in different locations, particularly with reference
to socioeconomic factors, was stressed. The idea of conducting studies
in panels of people suffering from cardio-respiratory disease was raised.
Emphasis was placed on the need to re-examine the concept of thresholds
of effect. It was accepted that a more formal collation of the results
of individual studies might be valuable.
(c)Development of methods
to discover the extent of life shortening identified by time-series studies
10. Statistical work underway
in the United States was noted. It was agreed that it would be sensible
to await the results of this work before considering funding related work
in the UK. The use of linked data on deaths and hospital admissions was
also agreed to be worth further exploration.
(d) Epidemiological
and volunteer studies of the effects of low concentrations of carbon monoxide
11. The recent US findings
of time-series studies linking carbon monoxide concentrations with admissions
to hospital for treatment of heart disease were raised. It was agreed
that the mechanisms of effects of carbon monoxide needed further study
and that emphasis should be placed on the effects of indoor exposures.
It was recommended that further epidemiological and volunteer studies
should not be funded at the moment.
(e) Volunteer studies to
look into the effects of particles on cardiovascular function
12. Members were aware that
some studies investigating these effects, such as the study in Birmingham,
were currently underway but felt that this was an important issue and
that further research to ascertain the mechanism of the effects of particles
on cardiovascular function should be pursued and encouraged further.
(f) A time-series
study including a daily analysis of particle composition
13. It was noted that at least
two studies investigating this area, namely those being conducted in Cardiff
and Edinburgh, were underway or planned. Therefore, it was concluded that
it was not necessary to recommend any further calls for research into
this issue at the present time.
(g) Volunteer exposure
to ultrafine particles
14. In general, the Committee
was in favour of pursuing such studies further, particularly since, with
the exception of studies carried out in Birmingham, there were no volunteers
studies looking at volunteers exposure to ultrafine particles. Two approaches
had been suggested: (a) concentration of the ambient ultrafine aerosol;
and, (b) preparation, de novo, of ultrafine particles of known
composition. Some Members felt that method (a) was difficult and that
studies should be approached with caution. Members felt that further work
was needed before the use of particle concentrators would be likely to
yield useful results. With regard to the second approach, it was noted
that some preliminary work undertaken at AEA Harwell had been encouraging
and should be pursued further.
15. Members agreed that volunteer
studies using ultrafine particles were, in principle, important, but that
issues such as particle composition, exposure concentrations and ethical
considerations would need to be very carefully addressed. The effect of
inorganic salts, including nitrates, was agreed to be worth further study.
(h) Work to improve
understanding of the effects of nitrogen dioxide
16. Members agreed that further work was needed to gain a clearer
understanding of the effects upon health of exposure to nitrogen dioxide.
The Committee recalled that its Quantification report had identified nitrogen
dioxide as a pollutant for which currently available evidence was not
sufficient to allow a confident quantitative estimate of effects on health
in the UK. It was noted that DH was likely to be under pressure to make
firmer statements of the gains to health that policies to reduce concentrations
of nitrogen dioxide would deliver. Finally, the point was made that covariance
of nitrogen dioxide and particles was a problem and made differentiating
the effects of these pollutants difficult.
(i) Studies that
focus on groups that are exposed to higher than average levels of pollution,
eg, at roadsides
17. This issue had already been discussed under the previous agenda
item.
(j) Study of the
effects of long-term exposure to current levels of pollutants
18. Whilst it was agreed that study of the effects of long-term exposure
to current levels of pollutants would inevitably be expensive and slow
in yielding results, Members agreed that the identification of existing
cohorts might be useful as this would lead to costs being significantly
reduced. Members also agreed that emphasis should be placed on estimating
past exposure to pollutants of members of cohorts. It was suggested that
the use of cohorts that contained geographically mobile individuals might
be of value as past-exposure profiles could be conducted. The possibility
of case-control studies was also raised.
(k) Studies of more
minor effects of air pollutants
19. It was agreed that there
was an important gap in knowledge of the extent of effects of air pollutants
on minor symptoms of illness. These effects were likely to impact on quality
of life and should be studied with a view to eventual quantification.
(l) Establishment
of a large panel of susceptible individuals (eg elderly with cardiovascular-respiratory
disease) and following them with respect to illness/death as related to
pollution levels
20. It was noted that a panel
of individuals likely to be susceptible to air pollutants had been established
in Birmingham: studies of this type were supported. In considering the
identification of susceptible individuals, Members noted that personal
perception of susceptibility did not always fit with actual susceptibility.
Anxiety due to perceived susceptibility was recognised as a potentially
important factor.
(m) Studies to define
whether the hospital admissions affected by air pollution are brought
forward or additional and whether they have different characteristics
from hospital admission in general (eg, in duration)
21. This issue was dealt with
under item (c).
(n) Studies to confirm
whether or not there is a threshold for the health effects of air pollution
22. It was agreed that identifying
whether or not there was a threshold for the health effects of air pollution
was critical and Members noted that if a threshold was identified, then
this would be reassuring since fewer people would be affected than had
previously been estimated in the COMEAP Quantification report.
(o) Studies of the
effects of air pollution on people's health related quality of life
23. This had been discussed
previously under item (k) and was regarded as an important issue.
24. It was agreed that nutritional
status might be included within one of the lifestyle categories. There
would be further discussion of priorities at the IEH review of the research
programme meeting and some amalgamation of the topics before a final call
for proposals is drawn up.
[ACTION:
Secretariat]
ITEM 6. INVESTIGATING THE HEALTH IMPACT OF LOCAL INDUSTRIAL EMISSIONS.
COMEAP/99/5
25. Discussion of this issue
is ongoing, and therefore this section of the minutes will not be released
at the present time.
ITEM 7. THE RELATIVE MERITS OF DIESEL v PETROL CARS AND LIGHT VEHICLES.
COMEAP/99/2
26. Members were reminded that
this topic had been discussed at the last meeting but that it had not
been possible to reach a conclusion at that time. The Secretariat had
agreed to take the issue away for further discussion with colleagues in
the Air Quality, Transport and Global Atmosphere sections of the Department
of Environment, Transport and the Regions (DETR) which had revealed the
complexity of the issue. The main conclusions were that in terms of acute,
direct effects on health in urban areas the balance seemed to tilt in
favour of petrol-vehicles equipped with catalytic converters. However,
as soon as the wider environment was considered, the problem became more
difficult with the choice depending upon whether there was greater concern
about the direct effects of particles in urban areas or the indirect effects
of CO2 on climate change. Attention was drawn to statements
A and B at paragraph 5c of COMEAP/99/2 which reflected the two situations,
and advice from Members was welcomed.
27. Detailed discussion of
the issues led to the following points being raised:
(a) The likely scale of impacts
at local as compared with global levels. It was suggested that local effects
on particle concentrations far outweighed likely effects of carbon dioxide
emissions on global warming.
(b) Members stressed that their
advice on this issue should not be taken as guidance on national policies
regarding the desirability of petrol versus diesel powered light vehicles
but only as guidance that could be provided to individuals facing a choice
between these types. The complexity of the problem was stressed and the
difficulties of providing sensible generic advice with out information
on intended patterns of use were noted. Members also stressed the different
factors that were involved in discussions regarding commercial as compared
with privately owned vehicles. The value of alternative methods of transport
including walking and cycling was raised
28. It was agreed that statement
B was preferable to statement A but that some further redrafting was needed.
The Secretariat undertook to do this and to clear a final version with
Members by correspondence.
[ACTION:
Secretariat, Members]
ITEM 8. GREATER OPENNESS
OF COMMITTEE PROCEEDINGS. COMEAP/99/2
29. This issue had been raised
briefly at the last meeting, and since then, the Committees on Toxicity
(COT), Mutagenicity (COM) and Carcinogenicity (COC) had issued a press
release dated 26 January on this subject. Attention was drawn to COMEAP/99/2,
which included a copy of this press release, together with background
papers for information. It was noted that all these Committees, would,
in future, have a greater degree of openness, and attention was drawn
to the proposals which had been agreed and were summarised at paragraph
10. Members were asked to consider the proposals set out under paragraph
3 of COMEAP/99/2, and each issue was discussed in turn. It was noted that
it would be important to come to some firm agreement, and the point was
emphasised that any major differences of approach taken by COMEAP compared
with the strategy adopted by its sister Committees would require careful
justification.
(a) Publication of Minutes
30. Members' views were requested
on whether the minutes should be anonymised from a future date; whether
they were content for the release of previous minutes (subject to members'
agreement in advance of the legislation); and whether they wished a summary
of the meeting to go onto the internet site after meetings or whether
the full minutes should go on when agreed.
31. With regard to future minutes,
Members were generally of the view that the full minutes should be placed
on the internet site, but that these must be anonymised in order to afford
individual Members some protection from being lobbied on particular issues.
It was also agreed that minutes should be anonymised from the present
meeting onwards. It was suggested that dissenting views could be covered
in a footnote. It was further suggested that the names of dissenting Members
should not be revealed.
32. There was some debate with
regard to the retrospective release of minutes of past meetings. The Secretariat
noted that COT/COM/COC had also debated this issue at length, and had
come to the conclusion that minutes should not be made available on a
retrospective basis. Members agreed with this view, and felt strongly
that, as a matter of principle, retrospective minutes should not be released.
Members had been appointed to the Committee on the understanding that
their proceedings were confidential, and therefore, it would be a breach
of that confidence to release past information. It was noted that the
Committee could feed into discussion on this following legislation and
agreed that the Secretariat should write to the CMO on behalf of the Committee,
expressing concerns about retrospection.
[ACTION:
Secretariat]
(b) Access to Committee
Papers
33. With regard to access to
committee papers, COT/COM/COC had decided to make finalised papers available
on request with any confidential information removed as necessary. The
COMEAP Secretariat felt that, subject to information provided in confidence,
both future and past papers provided to the Committee should be made available
on request. Members felt that there were similar concerns and arguments
here as discussed with regard to the retrospective release of minutes.
It was pointed out that many papers presented at the Committee were written
in the belief that the views expressed would remain confidential; therefore,
Members felt that they might have less freedom to express their views
if papers were released on demand. There was also a problem in releasing
papers retrospectively in that it would place a very large burden on the
Secretariat. After some further discussion, it was decided that it was
appropriate to make papers available on request from henceforth subject
to confidentiality, but that papers should not be released retrospectively.
It was further suggested that from now on all papers should be discussed
as to whether they should remain in confidence.
(c) Agenda
34. Members agreed with the
Secretariat proposal that a provisional agenda should appear on the internet
website about a month prior to future meetings.
[ACTION:
Secretariat]
(d) Open Meetings
35. Members were informed that
COT/COM/COC had decided to hold open meetings on specified topics to an
invited audience on fairly technical subjects. It was proposed that COMEAP
should hold either a half day meeting with the press and invited interest
groups to explain its work or hold an open session when the subgroup began
its work on air pollution and carcinogenicity. Members expressed mixed
feelings on this issue. Whilst it was acknowledged that some interaction
with the public, press or interest groups could be useful and improve
the image of the Committee, issues were raised about those representing
the Committee being unfairly burdened with being expected to answer questions
on almost any topic. However, it was pointed out that many Members of
the Committee were experienced in giving presentations and speaking at
conferences, and agreed on balance that with a good, well organised structure,
such an event could be beneficial to all interested parties. It was agreed
that the work on carcinogenicity would be a good opportunity to invite
outside interests to express views which the Committee could take into
account in its work.
(e) Statements
36. Members agreed that all
of the Committee's final statements should be placed on the DH internet
website, and that they should also appear in the Annual Report. It was
noted that statements were sometimes enclosed in correspondence with members
of the public and it was agreed that this should be continued in addition
to them being available on the website.
[ACTION:
Secretariat]
(f) Annual Report
37. It was agreed that the
Annual Report should be placed on the internet site in full form, and
that from 1997/98 onwards the report should be published as a free Department
of Health publication rather than a priced Stationery Office publication.
[ACTION:
Secretariat]
(g) Code of Practice
38. Members of the Committee
were reminded that the Cabinet Office Code of Practice had been circulated
at the last meeting. It was the intention of the Secretariat that this
should be formally adopted by the Committee. Therefore, it was agreed
that the Code of Practice would be recirculated and that Members should
write to the Secretariat as soon as possible if they had any problems
in accepting this code of practice.
[ACTION: Secretariat,
Members]
(h) Review of Procedures
39. Members agreed with the
Secretariat proposal that these revised committee procedures should be
reviewed after a period of 18 months' operation.
(i) Announcement
40. It was agreed that the
changes to the practices of the Committee should be announced via a press
release.
[ACTION: Secretariat]
ITEM 9. ORAL UPDATE ON COMEAP
UPDATE REPORT
41. Members were reminded that
it had been agreed earlier in the year that COMEAP would produce a report
updating the views given in the earlier COMEAP and MAAPE reports on the
effects of air pollutants on health. The approach suggested at that time
involved selected members taking responsibility for a specified pollutant
and producing a draft chapter for the final report. Work was currently
progressing on benzene and 1,3-butadiene, but some difficulties had been
experienced with the classical air pollutants. Part of this involved the
large expansion of the literature, particularly the epidemiological literature.
A further difficulty had arisen in that many of the epidemiological studies
dealt with more than one pollutant. Therefore if the review were to be
organised solely by pollutant a good deal of overlap would occur. It was
also noted that the pollutant-by-pollutant approach tended to ignore potentially
important interactions which was felt to be undesirable. Therefore, at
a meeting of the Secretariat and some Members held on November 26 1998,
a new strategy handling the classical pollutants had been produced. This
suggested that the report should be divided into 4 sections:
(a) Mechanisms of action. It
was intended that this section should deal with all the pollutants, highlighting
similarities and differences in how the pollutants were thought to act,
and emphasising integration. It was agreed that the Secretariat would
lead the drafting of this section, and taking advice and comments from
other toxicologists on the Committee as necessary.
(b) Physiological effects.
This was suggested as an alternative title for chamber studies and again,
it had been agreed that all the pollutants should be treated on a pollutant-by
pollutant basis, emphasising integration.
(c) Epidemiological studies.
It was suggested at the meeting in November 1998, that this section should
be cast in a new form, dividing the work in the first instance by type
of study. It was suggested that Professor Anderson should establish an
expanded database that would include all relevant epidemiological studies
and cover all the classical pollutants. It was acknowledged that this
would be a large task and therefore, it had been suggested that it might
be appropriate to employ a research assistant to undertake this assignment.
Once the database was established, Members would be invited to formulate
questions. The database would then be interrogated and charts produced
showing the relevant data. Those Members who posed questions would then
produce commentaries. For studies looking at the effects of long-term
exposure to air pollutants, it was noted that the literature was less
developed although some new work had appeared from, eg, the Swiss Study
of Air Pollution and Lung Diseases in Adults (SAPALDIA). It was suggested
that a separate review of this literature be undertaken by Professor Burney
(d) A final section discussing
the epidemiological results integrated as far as possible with the mechanistic
and physiological studies would complete the report. Members were content
with this new approach to producing the COMEAP update report.
42. It was agreed that benzene
and 1,3-butadiene would not be covered in this report but would be included
in the next planned COMEAP report on air pollution and cancer. Members
supported the suggestion that a database of epidemiological studies should
be established, and welcomed the interrogative approach, which was in
line with the approach used by Cochrane Review Groups. The point was also
made that it was important that a protocol listing all the variables to
be entered in the database should be drawn up as soon as possible; therefore,
it was emphasised that it would be helpful if Members could send their
questions to the Secretariat as soon as possible.
[ACTION:
Members]
43. There was some discussion
of the timescale for producing the report. Members were reminded that
there was a commitment to produce a draft report by the end of 1999. The
suggestion that the report be produced in sections was also raised, in
view of the fact that it was noted that the mechanistic section, which
was already at an advanced draft stage, was likely to have become dated
by the time the epidemiological sections were completed. This point was
acknowledged, but no firm decision was reached as to whether separate
publication of the mechanistic section of the report should go ahead was
reached.
ITEM 10. ORAL UPDATE ON
EVENTS SINCE THE MEETING HELD IN OCTOBER 1998
44. Members were informed of
the publication of the following DH and DETR reports: The Economic Appraisal
of the Health Effects of Air Pollutants; Review of the United Kingdom
Air Quality Strategy; An Economic Analysis of the National Air Quality
Strategy Objectives; and Source Apportionment of Airborne Particulate
Matter in the United Kingdom.
45. It was also noted that
with respect to the DH/DETR joint initiative on communication with the
public, it had been decided to take forward a proposal outlining research
into the public's attitude towards the air quality helpline messages and
health advice. It was intended that a piece of qualitative research, aimed
at vulnerable groups in particular would be undertaken in March, and that
it should be possible to present the initial findings to the Committee
for further discussion in June.
[ACTION: Secretariat]
ITEM 11. FUTURE WORK PROGRAMME
46. With respect to the Committee's future work programme, Members
were informed that it was intended that this should include a review of
the effects of air pollution on cancer to be undertaken jointly by COMEAP
and the Department's Committee on Carcinogenicity of Chemicals in Food,
Consumer Products and the Environment (COC). It was envisioned that this
work would start at the beginning of 2000. This would be followed by a
review of the effects of air pollution on cardiovascular disease. IEH
had also undertaken to produce reviews of the health effects of ambient
levels of arsenic, aldehydes and 1,3-butadiene. In response to a query
as to whether it was appropriate for COMEAP to look at the effects of
smoking on health, in particular with respect to the effects of carcinogens
in tobacco smoke, it was noted that this was the remit of the Scientific
Committee on Tobacco and Health (SCOTH), and therefore did not fall within
COMEAP's areas of responsibility. The most recent SCOTH report had been
published in 1998.
ITEM 12. ITEMS FOR INFORMATION
12.1 Health Effects
of Respirable Dust from Opencast Coal Mining. COMEAP/99/6
47. The letter from Dr Munro
was circulated for Members' information. Members were told that although
Dr Munro had requested that his paper was discussed by COMEAP, it was
considered more appropriate to include it within a more general evaluation
of the health effects of opencast mining in the future.
12.2 Cabinet Office Guidance. COMEAP/99/7
48. This paper was provided
for Members' information.
ITEM 13. ANY OTHER BUSINESS
49. There was no other business.
ITEM 14. DATES OF FUTURE
MEETINGS
50. The following dates for 1999 were noted:
Friday 18 June 1999
Friday 8 October 1999
51. The following dates for
2000 were also noted:
Friday 18 February
Friday 16 June
Friday 20 October
ACTION SHEET
| Paragraph Ref |
Action
|
Responsiblity |
|
35
|
Take account of comments
in drawing up research programme |
Secretariat |
| 28 |
Redraft statement B on
diesel v petrol engined vehicles and finalise by correspondence |
Secretariat/Members |
| 32 |
Write to CMO expressing
concerns aboutretrospective release of minutes |
Secretariat |
| |
Place anonymised minutes
on website once finalised with Members |
Secretariat |
| 34 |
Place provisional agenda
on website about a month before the meeting |
Secretariat |
| 36 |
Place finalised Committee
statements on website |
Secretariat |
| 37 |
Place Annual Reports in
full on website |
Secretariat |
| 38 |
Recirculate Code of Practice |
Secretariat |
| |
Write in if there are
any problems in adopting the above |
Members |
| 40 |
Issue Press Release to
announce changes in Committee procedures |
Secretariat/Press Office |
| 42 |
Write in with questions
to be input to epidemiological database |
Members |
| 45 |
Present initial results
of research intothe public perception of air quality helpline messages
and advice |
Secretariat |
|
About the Department