Dear Chief Environmental Health Officer
REVIEW AND ASSESSMENT OF PM10
BY LOCAL AUTHORITIES
Part IV of the Environment Act 1995 requires
every local authority periodically to review air quality in its
area. The Air Quality Regulations 1997 prescribe air quality objectives
for seven pollutants, to be achieved by 2005. Local authorities
have to consider the present quality of air and the likely future
quality of air, and assess whether prescribed objectives are likely
to be achieved by the end of 2005.
In December 1997 the Department of the Environment,
Transport and the Regions, the Welsh Office and the Scottish Office
issued guidance under section 88(2) of the Environment Act 1995
on a "Framework for Review and Assessment of Air Quality".
Paragraphs 3.23 and 3.24 of the guidance explained that the Government
would not be imposing a statutory deadline for completion of local
authority reviews and assessments and that it would be a matter
for local authorities to determine the frequency of reviews and
assessments of air quality. The guidance went on to say that "
. . . the Government expects local authorities to have completed
their reviews and assessments of air quality within two years
of Part IV of the Act coming into force" (i.e., the end of
The Government has recently published its proposals
for review of the National Air Quality Strategy (NAQS), and, in
particular, its proposals for revised and additional objectives
for the pollutants. During the review process, as a result of
the work of the Airborne Particles Expert Group, it became apparent
that the original PM10 objective
was unrealistic. Their work also revealed the importance of European
sources and the limit to which local authority action could control
levels of PM10. The Government has therefore proposed
replacing the objective in regulation with the proposed EC Air
Quality Daughter Directive Stage 1 limit values.
Following consultation, the Government may conclude
that the national objective for PM10 should be replaced
in regulation by the EC Stage 1 limit values. Such a change would
clearly have significant implications for the scale of work local
authorities undertake on the review and assessment of PM10
and the conclusions they reach. In addition, the likelihood that
an air quality management area would have to be declared for PM10
would be significantly reduced.
The analysis presented in the Review report
suggested that by 2005 with existing policies, even if atypical
meteorology occurred in that year, the daily EC Stage 1 PM10
limit value should be achieved at urban background locations across
most of the UK, with the exception of central London. There are
also likely to be exceedences of the limit value at busy roadsides
in some large urban areas and in the vicinity of some industrial
Quite clearly local authorities will wish to
take account of this. For as long as the situation with regard
to particles is unresolved, it would be sensible if local authorities
were to shift the focus of their review and assessment of PM10.
Local authorities in areas which are at risk of exceeding the
daily EC Stage 1 limit value are advised to carry on with their
review and assessment of PM10. Local authorities not
at risk of exceeding the EC Stage 1 limit value might consider
delaying further their review and assessment of PM10
by not going beyond the first stage review, until the Government
has completed its consultation on the revised PM10
objective and has announced its decision.
To help local authorities, and without prejudice
to the outcome of the consultation process, the Department is
developing technical material which may assist them in deciding
how best they might undertake work in this field. This technical
material will also include a discussion of the implication of
the use of different types of PM10 monitoring systems.
I aim to send this technical material on PM10 to you
in April this year.
The same difficulties do not arise for other
pollutants and local authorities should continue to press ahead
with the review and assessment of the other six pollutants for
which there are prescribed objectives (carbon monoxide, nitrogen
dioxide, benzene, 1, 3-butadiene, lead, and sulphur dioxide).
Air and Environmental Quality Division
Department of the Environment, Transport and the
12 March 1999
3 50 ug/m3 as a 24 hour running mean, to be achieved
with no more than four exceedences by the end of 2005 (as measured
by a TEOM or equivalent). Back
50 ug/m3 as a daily mean, to be achieved by 1.1.2005 with no more
than 35 exceedences and an annual average of 40 ug/m3 (as measured
by European gravimetric transfer reference sampler or equivalent,
roughly 7 to 20 exceedences using the TEOM or equivalent method). Back