|
 |
Meeting held on Friday 19th September 2003
Minutes of the meeting held on Friday 19th September 2003 in Room 136B
Skipton House, 80 London Road, Elephant and Castle, London SE1 6LH
Present:
Chairman:
Professor J G Ayres
Members:
Professor H R Anderson
Mr B Armstrong
Professor D Derwent
Professor K Donaldson
Professor S Holgate
Professor D Laxen
Dr V Murray
Professor P Poole-Wilson
Dr V Stone
Professor D Strachan
Professor D Walters
Secretariat:
Dr R Maynard
Dr H Walton
Miss J Cumberlidge
Ms I Lindup
Mrs S Haider
Assessors: Mr M Meadows
In Attendance: Dr J Townend
ITEM 1. APOLOGIES FOR ABSENCE
- Apologies for absence were received from Mrs Alice Lambert, Mr Fintan
Hurley, Dr John Pritchard, Dr Paul Harrison, Professor William MacNee
and Professor Anthony Frew.
ITEM 2. MINUTES OF THE MEETING HELD ON 20th JUNE 2003. COMEAP/MIN/2003/2
- The minutes were considered page by page and the following amendments
made:
(i) Page 2, Line 19 was amended to read: "….had also been appointed
to…."
(ii) Page 4. It was noted that lines 30-33 contained a quadruple negative.
The Secretariat agreed to redraft these lines.
(iii) Page 5, line 23 was amended to say: "…correlation and a little
used analytical…".
(iv) Page 5, Lines 33-34. It was suggested that it was inappropriate
to quote a key reference within the body of the minutes and that the
reference should be alluded to only. The Secretariat pointed out that
this reference had not been cited in any of the papers hence its inclusion
in the minutes. However, the Chairman felt that it should not be cited
in the minutes and that this problem might be resolved by use of a
footnote. The Secretariat agreed and also undertook to amend lines
26-36 as a whole as some further inaccuracies were identified.
(v) Page 11, line 26 should say and/or
(vi) Page 11, Lines 32-33 - it was felt that this did not adequately
explain the pathological/physiological effects observed and it was
agreed that a further form of wording would be agreed.
(vii) Page 11, Lines 35-37 - it was noted that these paragraphs repeated
the reference to exercise in line 25. The Secretariat agreed to redraft
these paragraphs.
- Subject to the above amendments the minutes were agreed as an accurate
record of the meeting.
ITEM 3. MATTERS ARISING
3.1 Statement on Carbon monoxide and Nitrogen Dioxide indoors
- The Secretariat reported that publication of the COMEAP statement
had been delayed.
Public Availability: It was further noted that the rest of paragraph
4 should not be made publicly available at the present time since
it referred to work that was currently in progress and not in the
public domain.
3.2 Swimming pools and asthma
- The Secretariat reported that the COMEAP statement had been placed
on the website. Two issues had been raised by Members in earlier discussions:
the first regarding the statistical analysis used by the authors of
the original study and the second, conclusions which the authors have
reached regarding changes in levels of surfactant. Letters to the
journal carrying the original report were being drafted by Members
of the Committee. Some discussion on the use of letters to a journal
regarding material considered by COMEAP followed. It was agreed that:
i. Only the Chairman should write on behalf of the Committee. In this
case the text would be agreed by COMEAP members.
ii. The Committee might encourage Members to write on their own behalf
and of course Members might write without reference to the Committee.
- It was noted that an opportunity had been lost in drafting the COMEAP
statement. This related to emphasising the need to control carefully
chlorine levels in swimming pools and that this was the responsibility
of those who maintain such facilities.
3.3 Deadlines for report contributions
- The deadlines for contributions to the Cardiovascular and the Asthma
Sub-groups' reports were noted to be 15 October.
3.4 Dates for meetings in 2004
The following dates were noted:
Friday 27 February;
Friday 25 June;
Friday 22 October.
- The Chairman reported that Emma Hellingsworth had resigned from
the Department of Health. He thanked her on behalf of the Committee
for all the work she had done on their behalf in the past few years.
The Committee joined with the Chairman in wishing Emma luck for the
future.
3.5 Report from the Asthma Sub-group
Public Availability: It was further noted that paragraph 9 should
not be made publicly available at the present time since it referred
to work that was currently in progress and not in the public domain.
ITEM 4. REPORT OF CARDIOVASCULAR SUB-GROUP
- The Chairman opened by noting that Professor Poole-Wilson was keen
for the cardiovascular community in the UK to be apprised of the findings
of the group as soon as possible. Meetings to facilitate this were
currently being arranged. The Chairman also welcomed Dr John Townend,
a Member of the Cardiovascular Sub-group, to the meeting. It was noted
that a workshop which would be attended by cardiologists had been
arranged for December 2nd 2003.
- General discussion of the report led to Members questioning whether
the report was seeking to identify a general relationship between
air pollutants and cardiovascular disease or, perhaps, to identify
the components of the air pollution mixture most closely associated
with cardiovascular disease. The Chairman informed Members that the
report had focused largely on particles, but that the Sub-group was
well aware of the need not to forget the possible effects of gaseous
air pollutants. It was agreed that Members of the Sub-group would
follow up this point.
- Members of the Sub-group then gave a series of presentations. These
presentations were illustrated with visual aids. These have been circulated
to Members of the Committee but are not reproduced in these Minutes
because they represent the preliminary work of a project which is
still in progress. Some of the points made in the illustrative material
may need to be changed: the contents of all the visual material presented
will appear in the final report, albeit in revised form.
Public Availability: It was further noted that paragraphs 13 -
26 should not be made publicly available at the present time since
it referred to work that was currently in progress and not in the
public domain.
- The Chairman thanked all those who had made presentations
and agreed to take comments into consideration.
ITEM 5. PRESENTATION ON THE EFFECTS OF OZONE
- The presentation was opened by explaining that its purpose was
to summarise the evidence which the Committee had considered so far
and its conclusions to date.
- Members were unanimous in congratulating Dr Walton on the work
she had done on this topic: no other examination of the problem had
provided such a detailed account. During the discussion a number of
interesting points were made.
- The question of genetic susceptibility was raised on a number of
occasions. It was pointed out that a number of genes had now been
shown to be associated with increased susceptibility to ozone. One
such gene seemed to influence the extent of the decrement in lung
function seen on exposure to ozone whilst another seemed to control
the inflammatory response in the airways to ozone. The functioning
of the former was better understood than that of the latter. It was
agreed that the problem of sensitive groups in the population deserved
greater examination. It was noted that it had been suspected for some
time that perhaps 10% of the population were more susceptible to ozone
than might have been expected and it was wondered whether this susceptible
group might be explained by variations in genetic profiles. It was
agreed that identifying susceptible individuals was currently difficult
as no satisfactory phenotypic markers were available.
- In discussing the relationship between day-to-day variations in
levels of ozone and a wide range of effects on health it was agreed
that these data might be compatible with fitting either a linear or
a curved model. It was concluded that the use of a linear model was
cautious and appropriate. It was accepted, then, that there was no
firm evidence to support the contention that the effects of ozone
were characterised by threshold. Some Members wondered whether ecological
studies such as those, mainly, considered here were of much value
in detecting thresholds. It was pointed out that panel studies and
wider mechanistic evidence might be more useful in this regard. It
was suggested that the report would need to explain the nuance between
concluding there was evidence for an association and concluding that
there was a causal relationship.
- Members pointed out that in 2000, WHO had recommended a guideline
for ozone of 60 ppb (8 hour average). It was noted that this was based
largely on chamber studies and not on as detailed an examination of
time-series studies as had been undertaken by Dr Walton. It was also
noted that the WHO report, whilst recommending a guideline of 60 ppb,
had left open the possibility of effects at lower levels.
- Members commented that with regard to the panel studies on lung
function, if there was a threshold of effect (whilst noting that the
time-series do not support this contention) they did not feel that
this threshold was likely to be at more than 50 ppb. It was also noted
that the p value of 0.934 did not seem to match the confidence intervals
in the table of summary estimates for the lung function studies. It
was suggested that in work designed to look at the quantification
of the benefits to health that might accrue from reductions in levels
of ozone, sensitivity analyses using a series of notional thresholds
at 30, 40 and 50 ppb might be useful.
ITEM 6. OZONE POLLUTION EPISODE REPORT - COMEAP/2003/16
- It was reported that 2003 had been notable for air pollution generally.
High levels of ozone had been recorded both earlier and later in the
year that in any previous year. An episode of high levels of ozone
had occurred in August, this had been associated with very warm weather.
Provisional figures suggested that levels in London had been the highest
for a decade. It was also noted that Europe as a whole had been exposed
to high levels of ozone, those in Paris being slightly higher than
those in London. The highest levels recorded in August were, however,
only about half those recorded in 1976.
- A short presentation outlining the meteorology of the ozone episode
was given and Members agreed that this was helpful.
ITEM 7. HEALTH EFFECTS OF THE OZONE EPISODE - COMEAP/2003/17
- The Secretariat reported that Mr John Stedman (NETCEN) had undertaken
a preliminary calculation of the impact of the August ozone episode
using the methodology deployed by COMEAP in its 1998 QUARK report.
This work was intended for publication in the peer-reviewed literature.
- Discussion of this work made it clear that the uncertainties inherent
in applying a dose response function at the extreme of the range of
concentrations used to generate that function should be stressed in
any report of the work. It was also noted that levels of particles
may well have been raised at the same time as those of ozone and that
the addition of the outputs from single pollutant models (ie adding
up the deaths attributable to particles and ozone) might not be wise.
It was noted that COMEAP had used single pollutant models in the QUARK
report (1998) but had counselled against the addition of the results
of these calculations. The possibility of deploying multi-pollutant
models in future calculations was discussed though it was accepted
that comparatively few studies had used such models. The effects of
temperature during August were also considered and it was wondered
how these would be separated from those of ozone. It was suggested
that a comparison of the 1976 episode (similar temperatures, higher
ozone concentrations) and the 2003 episode might be helpful. The summer
of 1990 was also mentioned when temperatures were high and ozone did
not rise as expected. It was also agreed that a proper epidemiological
study, containing information on date of death rather than death registration,
breakdown by cause and age and analysis of the effect of temperature
as well as ozone, was required.
ITEM 8. ANY OTHER BUSINESS
- The Secretariat pointed out that Members' contact details had been
circulated. Members were asked to check these and update them if necessary.
- The Chairman pointed out that attendance at meetings was being monitored
and that this would form part of the three-yearly assessment of Members
which was required of the Chairman by the Department of Health in
accordance with the Office of Science and Technology guidelines.
DATE OF NEXT MEETING 14th November 2003
Secretariat 2003
|
|
|
|
You
are here: 
