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1.
Introduction.
In the UK the implementation of the EU
Framework Directive and the subsequent Daughter Directives is a matter for
Central Government and the devolved administrations in Scotland, Wales and Northern Ireland alone. If there were formal regional assemblies in England it is possible that these would
have some measure of responsibility for the achievement of the Limit Values in
the European legislation but under the present system Local Authorities (such
as City Councils, District Councils and Metropolitan Councils) have no such
responsibilities.
This creates potential problems with the achievement of the Limit
Values because, although measures implemented at national level are expected to
achieve compliance in most locations, there will almost certainly be residual
areas (hot-spots) where the Limit Values will not be achieved. Because many (but by no means all) of these
areas are small it is almost impossible for a central government to implement
measures to remedy this problem. To
remedy this problem the UK Government has implemented legislation to require
Local Authorities to implement a programme of Local Air Quality Management
aimed at tackling these hot-spots.
2. Legislation.
The primary relevant UK legislation is Part IV of the
Environment Act, 1995. This requires all
Local Authorities in the UK to carry out a staged process of
Review and Assessment (R & A) of air quality in their areas. As originally introduced this is illustrated
in Figure 1 and involved a 3 stage process.
This allowed Local Authorities to proceed directly from Stage 1 to Stage
3 if they felt this was justified. If it
was predicted that one (or more) of the objectives set out in Regulations made
under the Environment Act would be exceeded, then one or more Air Quality
Management Areas (AQMA) should be declared and a Local Air Quality Action Plan
(AQAP) developed. Objectives for the
purposes of Local Air Quality Management (LAQM) were set for 1,3 butadiene, benzene, carbon monoxide, lead, nitrogen
dioxide, particles as PM10 and sulphur dioxide. A further objective for ozone was included as
a national target as local measures cannot influence ozone concentrations in
that locality.
The Act also required the Secretary of State to develop an Air Quality
Strategy for the UK with objectives to be achieved in
the future. The Act also gave the
Secretary of State powers to produce guidance to
assist Local Authorities in the LAQM process.
The original objectives for the purposes of LAQM were contained in the
Air Quality Regulations, 1997. These
were subsequently amended by the Air Quality (England) Regulations, 2000 which relaxed
the objectives for particles, measured as PM10, but tightened other
objectives, mainly by advancing the date for achievement. Further, detailed, amendments were made in
the Air Quality (England) (Amendment) Regulations, 2002 to
reflect Limit Values contained in the Air Quality Daughter Directives.
The objectives for LAQM in
the UK are closely based upon the EU
Limit Values but, in general, are to be achieved earlier than the Limit
Values. One consequence of this is that
in relation to emissions from industry it is possible to set more stringent
requirements than BAT (best available technology) or BATNEEC (best available
techniques not entailing excessive cost) in order to meet the EU Limit Values
but not in order to achieve the UK objectives.
3. Implementation
in Bristol.
The Stage 1 (or screening) R & A showed that there were many roads
with sufficiently heavy traffic to indicate a probability of the annual average
objective for nitrogen dioxide (40 µg m-3) being exceeded. There were also concerns that the original
objectives for PM10 would not be achieved and emissions from
industry presented a possibility that objectives for
lead and sulphur dioxide might also be exceeded.
The original legislation provided for a Local Authority to progress
straight from Stage 1 R & A to the very detailed Stage 3 R &A if it
felt that the intermediate Stage 2 R & A was not necessary and this was the
path followed by Bristol.
The outcome of this was that there were predicted exceedences of the
annual average objective for nitrogen dioxide in the central areas of the city,
on major roads leading to the central area and round a motorway to the north of
the city. There were also potential
exceedences on the PM10 objectives.
As a result of this 2 AQMAs were declared in May 2001 and the process
of re-examining and refining the Stage 3 R & A to confirm the need for the
AQMA. In parallel to this the process of
developing the AQAP was initiated. These
processes involved close co-operation between the air quality team, who carried
out the R & A work and the Transport Planners who developed the AQAP.
The Stage 4 R & A confirmed the need for the main (central) AQMA,
with a number of minor changes to the boundary, but concluded that the motorway
AQMA was not justified. This conclusion
was the result of refinements in the modelling software which previously had
over-predicted concentrations of nitrogen dioxide near motorways. Concerns still remained about PM10
but it was predicted that the revised objectives would probably be met. As a result of this an order was made
amending the boundaries of the AQMAs to reflect the new information. A political decision was taken to retain the
motorway AQMA pending further monitoring.
It should be noted that this just reflects the situation in Bristol.
In other areas AQMAs have been declared on the basis of single streets,
a number of individual streets or, in some cases the whole Local Authority
area. The majority of AQMAs in the UK have been declared on the basis
of the annual average nitrogen dioxide objective, with road traffic as the main
source but some have been declared on the basis of PM10 from
industry, PM10 from domestic combustion, sulphur dioxide from
industry, sulphur dioxide from domestic combustion and in one case sulphur
dioxide from shipping.
4. Subsequent
developments.
Since the original Strategy and the associated guidance were produced
both have been reviewed and updated. In
the case of the Strategy additional pollutants (PAHs) have been added and new
objectives proposed. In the case of the
guidance the original 3 stage R & A process has been replaced by a rolling
programme of Updating and Screening Assessments, Detailed Assessments (if
necessary) and Progress Reports. A
programme for these has been set out to 2010. |
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