COMMITTEE
ON THE MEDICAL EFFECTS OF AIR POLLUTANTS
Minutes
of the meeting held on Friday 22 June 2001 in Room 136/7B Skipton House,
80 London Road, Elephant and Castle, London SE1 6LH.
Present:
Chairman: Professor
S Holgate
Members: Dr
B Armstrong
Professor J Ayres
Professor P Burney
Professor K Donaldson
Dr A Gavin
Lord T Harris
Professor R Harrison
Mr F Hurley
Professor W MacNee
Dr J Pritchard
Professor A Seaton
Professor D Strachan
Professor D Walters
Secretariat: Dr
R L Maynard
Dr H Walton
Miss J Cumberlidge
Assessors: Dr
P Harrison (IEH)
Dr J Dixon (DEFRA)
In
attendance: Ms E Jenkins (DH)
Ms C Townsend (DH)
ITEM 1. APOLOGIES
FOR ABSENCE AND ANNOUNCEMENTS
- Apologies for absence
had been received from Professor R Anderson, Professor P Blain, Professor
P Poole-Wilson, Professor R Richards, Dr S Coster and Dr M Williams.
- The Chairman
welcomed Dr Janet Dixon who was attending as the DEFRA representative
on behalf of Dr Coster and Dr Williams.
- The Chairman
reminded Members that any interests should be declared as the Committee
progressed through each item.
ITEM 2. MINUTES
OF THE MEETING HELD ON 9 FEBRUARY. COMEAP/MIN/2001/1
- There was one amendment
to the minutes: on page 1 it was noted that Dr Brian Miller was from
the Institute of Occupational Medicine (IOM) and not the Institute for
Environment and Health as stated. Subject to this amendment, the minutes
were agreed as an accurate record of the meeting.
ITEM 3. MATTERS
ARISING
3.1 Long-Term
Effects of Particles on Health. COMEAP Statement and Report
- The Secretariat
reported that the COMEAP Statement and Report on the Long-Term Effects
of Particles on Health had been published at a Press Launch on 3 May
2001, and was available on the COMEAP website under the Committee statements
section. The launch of the report attracted some media and press attention;
relevant press cuttings had been circulated to Members by post.
- It was noted that
the COMEAP Statement and Report were based on the findings of the report
from the IOM. Members asked when this report was likely to be published.
Mr Hurley replied that the report needed a short preface explaining
that in some areas, it was slightly dated. Once this was incorporated
and the references completed, it was intended that a final version of
the report would be published. It was noted that negotiations were taking
place with DH to have the report placed on the COMEAP website. Two papers
intended for submission to the peer-reviewed literature were in preparation.
Meantime, it was noted that the draft submitted to DH in the early part
of 2000 was available to members of the public on request.
[ACTION:
IOM, Secretariat]
3.2 Research
Funding
- It was noted that
since discussion of this issue at the last meeting there had been some
further developments and current indications were that funding for the
air pollution programme was likely to resume this year with money being
available over a 3-year period. The call for proposals would not be
published until Ministers had been informed.
ITEM 4. TIME-SERIES FOR THE
EFFECTS OF PARTICLES ON ADMISSIONS TO HOSPITAL FOR TREATMENT OF CARDIOVASCULAR
DISORDERS. COMEAP DRAFT STATEMENT. COMEAP/2001/8
- Members were reminded
that this item had been discussed at the last meeting when various comments
had been made on the draft statement. These had been incorporated and
a new draft presented as COMEAP/2001/8. Members’ comments on the new
draft statement were welcomed.
Paragraph 1
- Discussion focused
on the last sentence of the paragraph. Some Members questioned the use
of the word "prudent" as being a risk management policy view
rather than a view based on science alone. It was agreed that this sentence
should be deleted and that paragraph 2 should focus on Members’ perceptions
of the strength of the evidence and on the use to which such evidence
might be put. The phrase "more likely than not to be causal"
was agreed.
Paragraph 2
- Members agreed
that whilst certainty regarding the link between exposure to particles
and effects on the cardiovascular system was not yet possible it was
important to reflect their view that the epidemiological evidence was
persuasive and that it would be wrong to be too tentative about saying
so. It was noted, by way of comparison, that the evidence in this area
was rather stronger than that bearing on the effects of long-term exposure
to air pollutants on which the Committee had taken a firmer stance.
- It was also felt
that paragraph 2 should be simplified: terms such as sensitivity analysis
should be explained to make the Committee’s view accessible to the public.
The Secretariat pointed out that the statement had several uses, informing
the public being one, but making the Committee’s views clear to other
government departments involved in developing policies to reduce levels
of air pollutants was also important. This was accepted.
- Members discussed
the technical point of whether diagnostic uncertainty would lead to
weakening or strengthening of the coefficient linking particles and
effects on the cardiovascular system. It was agreed that a weakening
effect was more likely than the alternative.
Paragraph 3
- The use of the
term "confidence interval" was discussed. It was agreed that
this should stand as the interval recorded was the confidence interval
derived from a meta-analysis of original studies.
- It was agreed that
the Secretariat should redraft the statement, simplifying the wording
where possible and including footnotes to deal with the technical points
noted above. It was noted that the need to make clear whether the coefficient
referred to concentrations of particles measured using the Tapered Element
Oscillating Microbalance (TEOM) technique or a Gravimetric technique
should be clarified. This point was important to DEFRA: the TEOM method
is in general use in the UK. It was agreed that the new draft would
be circulated to Members by post.
[ACTION:
Secretariat]
ITEM 5. CARBON MONOXIDE. COMEAP/2001/9
- The Secretariat
explained that concern about possibly long-lasting neurological effects
of prolonged exposure to low concentrations of CO was increasing. It
had long been accepted that acute exposure produced neurological effects
but it was generally believed that these disappeared as soon as COHb
levels returned, post-exposure, to normal. The new perception raised
the question of the possibly long-lasting effects of exposure to CO
produced by, for example, malfunctioning gas heating appliances or a
coke-fired boiler. The Secretariat drew attention to COMEAP/2001/9 and
to a chapter (appended) from a recent book on neurotoxicology. Members
were asked for preliminary views on the issues raised.
- It was noted that,
in recommending an Air Quality Standard for CO, EPAQS had adopted a
simple approach based on the kinetics of the uptake and release of CO
by the body. Such data related to acute exposures. It was accepted by
some Members that it was possible that long-term exposure to low concentrations
might produce neurological effects. A parallel with the effects of solvent
exposure was drawn. It was noted that cigarette smokers were exposed
to carbon monoxide and typically had COHb concentrations of between
3 and 12%. However, Members were not persuaded that the possibility
of long-term effects of prolonged low level exposure could be set aside
on the basis of this observation. It was noted that subtle neurological
effects could be detected in heavy smokers.
- Members stressed
that recognition of the effects of low level exposure was difficult
as the symptoms produced were often vague and commonly caused by other
factors. That cases were being missed was accepted as likely. Members
commented that neurological effects were difficult to explain on the
basis of hypoxia alone and that other mechanisms were likely to be involved.
- The increased susceptibility
of some groups including the fetus and infant was noted. It was stressed
that the fetus was normally exposed to low oxygen levels: a left shift
of the oxyhaemoglobin dissociation curve and a reduced oxygen content
in fetal blood, both of which are effects of carbon monoxide exposure,
would rapidly render the fetus hypoxic. The sensitivity of the developing
central nervous system was noted. Concern was also expressed about the
possibility of exposure of babies to low concentrations of CO: babies
are often placed in a heated room but cannot move out on their own and
are thus at increased risk of exposure to CO produced by faulty heating
devices.
- It was pointed
out that studies of indoor CO concentrations had revealed a range of
concentrations. Most gave no cause for concern but some houses had significantly
increased levels. This was due not only to malfunctioning heating devices
but also to misused devices.
- It was noted that
there was considerable public concern about the issue. The need to stress
the value of CO detectors was emphasised though it was appreciated that
these, in general, warned only of high concentrations of CO and did
little to alert residents to the risk of prolonged exposure to lower
but still potentially dangerous concentrations.
- Members were aware
of increased litigation in this area and that at present it was not
clear one way or the other that prolonged low level exposures caused
harm. However, parallels with solvents, lead and nitrogen dioxide were
drawn and it was agreed that further study of the problem was called
for. Mechanistic studies were suggested. It was accepted that the problem
was a difficult one to address by epidemiological methods: confounding
factors and the possibility that CO would be acting as an indicator
pollutant for a complex mixture rather than as a causal factor per
se was stressed.
ITEM 6. INDOOR AIR QUALITY GUIDELINES.
REQUEST FOR ADVICE. COMEAP/2001/10
- The Secretariat
introduced this paper. Difficulties likely to be encountered if guidelines
on indoor air quality were introduced were stressed. On the other hand,
the concept of developing enhanced guidance (which might include some
numerical guidelines) was seen as a potential way forward. This approach
was welcomed by Members. The importance of distinguishing between the
work environment and the home environment was raised as were concerns
regarding the environment of the office worker. Concerns about pollutants
leaking into homes from adjacent premises were also raised.
- It was suggested
that the key areas to address were:
(i) Possible
interactions between the effects of gaseous pollutants and allergens.
(ii) Humidity
and temperature was also important for comfort but it was harder to
define optimal levels as this was a broader area. A good deal of work
has been done on this and there are graphs identifying the so-called
"comfort zones".
- Members stressed
the importance of both radon and tobacco smoke as indoor pollutants
but accepted that these were outside their remit for advice.
- Returning to the
idea of developing enhanced guidance, the Committee asked for information
on progress in other countries – particularly in those where indoor
air quality standards had been established. The need to focus on "big
health problems" was stressed: at present it was difficult to see
which major health problems would be solved by improving indoor air
quality and more work was needed on this. Whilst accepting that development
of enhanced guidance was a useful way forward some Members felt that
the guidance would need guidelines to provide the urge to monitor and,
if necessary, improve indoor air quality. It was accepted that improvement
of the indoor environment in peoples’ homes could only be addressed
on a voluntary basis and that the key was the provision of better information.
[ACTION:
Secretariat]
- It was agreed that
the Secretariat’s initiative in holding a further meeting to discuss
possible ways forward should be supported. It was agreed that Committee
papers on specific aspects of indoor air pollution might be commissioned.
[ACTION:
Secretariat]
ITEM 7. CODE
OF PRACTICE FOR SCIENTIFIC ADVISORY COMMITTEES. COMEAP/2001/11
- The Secretariat
reminded Members that the Office of Science and Technology (OST) had
produced a paper in July 2000 entitled "A Consultation Document
on a Code of Practice for Scientific Advisory Committees." Members
had been asked to comment on this paper at the October 2000 meeting.
OST reviewed the comments received and subsequently produced a revised
paper in March 2001 entitled "Code of Practice for Scientific Advisory
Committees: Draft for Second Round." It was noted that Members’
comments on the first draft had been taken into account in the new version.
The Secretariat asked that any further comments be submitted directly
to OST by June 27.
[ACTION:
Members]
ITEM 8. PAPERS
FOR INFORMATION
- The following papers
were circulated for information:
Peters A,
Dockery DW, Muller JE, Mittleman MA. Increased particulate air pollution
and the triggering of myocardial infarction. Circulation 2001; 103:2810-2815.
- It was noted
that this paper had attracted some press and media attention and Members’
comments on the study were welcomed. The Secretariat commented that
the effects of exposure to air pollution on cardiovascular disease was
becoming an important area, and that it intended to convene a meeting
of several experts in this field in order to discuss the matter further
in the near future.
- It was suggested
that the paper by Peters et al might be demonstrating a diurnal
variation in the incidence of heart attacks but others pointed out that
the paper had attempted to take this effect into account. Several Members
were encouraged that studies of this type were now emerging and becoming
increasingly important in the air pollution research field. It was agreed
that the paper demonstrated a novel approach, but the comment was made
that in interviewing individuals, questions could have been asked about
their activity patterns. It was felt that this had been an opportunity
missed: reference was made to other studies that had shown that, for
example, eating a heavy meal had an effect on the risk of having a heart
attack.
Laden et al.
Association of fine particulate matter from different sources with
daily mortality in six US cities. Environ Health Perspect 2000; 108:941-948.
- It was noted that
this paper had been circulated to Committee members by post. Members’
comments on the paper would be welcomed.
[ACTION:
Members]
ITEM 9. FUTURE
WORK PROGRAMME
- The Secretariat
explained that DH officials were currently discussing the future needs
for health advice on air pollution with officials from DETR (now DEFRA).
Due to the general election, future plans for reviewing objectives in
the National Air Quality Strategy and consequent needs for health advice
had not been discussed with Ministers and were not fully clear yet.
Some of the ideas, not necessarily in order of priority were as follows.
- A further look
at dose response functions for acute mortality, respiratory hospital
admissions and cardiovascular hospital admissions after publication
of papers from the APHEA and NMAAPS studies.
- Updating of
the previous QUARK calculations to take account of any changes in
the above and the reductions in pollutant concentrations since 1996.
- Consideration
of use of GP consultation dose-response functions for quantification.
- Review of results
of panel studies for particles including the PEACE study (needed
before EC review in 2003).
- Long-term effects
and other quantification issues for nitrogen dioxide (the annual
mean objective is difficult to meet but the importance of the health
effects are uncertain).
- Is there a
threshold for the effects of ozone? (With the reduction in nitrogen
oxides in urban areas, ozone levels in urban areas are rising but
at levels below the possible threshold. Whether there is a threshold
or not is crucial to judging whether this trend is of concern.)
- Air pollution
and heart disease. A rapidly growing area of research at present.
COMEAP has commented on certain aspects but not given an overall
view.
- Asthma review.
- Members agreed
that it was timely to revisit the issue of dose-response functions since
there had been much new information since the quantification report
had been written in 1998, and there was a need to update this with any
new dose-response functions supported by recent literature. Work on
ozone and nitrogen dioxide would tie in with this. There was considerable
support for the idea of further work on the effects of exposure to air
pollution on heart disease, and Members also agreed that there was a
need to update the Committee’s views on asthma and air pollution. Since
the COMEAP report on this subject had been published in 1995, new information
had merged, and that particular report was now felt to be dated.
- Other issues raised
included consideration of the effects of pollution from incinerators
on health, and also a consideration of the health effects of inhalation
of dioxins. It was noted that the latter issue would overlap with the
work of the DH Committee on Carcinogenicity (COC) and the Committee
on Toxicity (COT). The COT was currently considering this issue with
regard to dioxins in food. Inhalation of dioxins was not generally thought
to pose a problem in terms of health effects since dioxins were not
well absorbed by the lung. The issue of carcinogenic air pollutants
was raised. The Secretariat explained that COC had been considering
a prioritisation scheme which included several carcinogenic air pollutants.
Members were asked to submit further ideas on the work programme in
writing to the Secretariat.
[ACTION:
Members]
ITEM 10. APPOINTMENT
OF NEW MEMBERS TO THE COMMITTEE
- It was noted that
there had been little progress on this matter since the last meeting
due to pressures of work arising during the Foot and Mouth Crisis. There
had been one or two additional applications received since the last
meeting, and the sifting process was underway. A date for interviewing
prospective candidates was to be arranged shortly. It was explained
that Dr Anna Gavin would be reappointed directly to the Committee, but
that Professor Strachan, Mr Hurley and Lord Harris would only be reappointed
subject to competition with other candidates. It was noted that Professor
Burney and Dr Sarah Walters were leaving the Committee and both were
thanked for their hard work. The Secretariat commented that Professor
Ayres had applied for the post of Chairman, which was being vacated
by Professor Holgate at the present meeting. Professor Holgate was presented
with a framed certificate signed by CMO and formally thanked for his
outstanding contribution to the work of the Committee.
ITEM 11. ANY
OTHER BUSINESS
11.1 Foot
and Mouth: Effects on Health of Emissions from Pyres used for Disposal
of Animals
- This document was
circulated previously to Members for information and can be found on
the DH website at: http://www.doh.gov.uk/fmdguidance
11.2 Foot
and Mouth Disease: Disposal of Carcasses. Programme of Monitoring
for the Protection of Public Health
- This was circulated
for information.
ITEM 12. DATE
OF NEXT MEETING
- The following date
was noted: Friday 2 November 2001.
ACTION
SHEET
|
Para Reference
|
Action |
Responsibility
|
|
6
|
Add
a short preface to the IOM report
noting that it was slightly outdated
and complete the reference list |
IOM
|
| |
Continue
negotiations regarding placing
the report on the COMEAP website |
Secretariat
|
| 14 |
Update
the COMEAP statement in light of
discussion and circulate to Members for
comment by correspondence |
Secretariat/
Members
|
| 25 |
Provide better
information to the public regarding
the indoor environment
|
Secretariat
|
| |
Convene
a meeting to discuss the issues raised
further and commission COMEAP papers
on specific aspects of indoor air pollution
|
Secretariat
|
| 27 |
Send
in any further comments on Code of
Practice directly to OST by June 27 |
Members
|
| 31 |
Submit
any comments on the paper by Laden
et al to the Secretariat |
Members
|
| 34 |
Submit
any further ideas/comments on the
future work programme to the Secretariat
as soon as possible |
Members
|
|
About the Department