A Review and assessment of air quality in the Borough

The Borough Council undertakes, in conjunction with all Shropshire Councils, a Review and Assessment of Air Quality within the Borough. This allows the Council to identify any areas of concern. Actions can then be developed to reduce any problems highlighted

The Council carried out the first Review and Assessment of Air Quality in 1999, and the results were published in 2000.

The pollutants under review and the dates when the Air Quality Objectives are to be achieved are shown in the table below. The Review aimed to discover whether the set objectives to keep a certain pollutant below a certain level are to be met by the date shown. Where several dates are shown for a pollutant, there are different objectives for the pollutant, which have specific different target dates.

The Review and Assessment process

The Government has recommended a phased approach to air quality Review and Assessment involving three stages, with each stage reducing in its scope but increasing in detail in order to more accurately assess local air quality.

All Shropshire District and Borough Councils have worked together with Telford and Wrekin Council, the Environment Agency and Shropshire County Council to undertake the Review and Assessment in partnership. The group, known collectively as the Shropshire Local Air Quality Management Group, has followed the guidance given by Government and has produced two previous reports on the Review and Assessment process:

• Stage 1 April 1999
• Stage 2 October 1999

These reports have been submitted to and approved by the Department of the Environment, Transport and the Regions as complying with statutory guidance.

Stage 1 was a simple scoping exercise to produce a basic inventory of:

1. The processes (such as industry, road transport, domestic sources) in the study area that emit one or more of the pollutants of concern.
2. And of these processes, those that have the potential to exceed the current standards for air quality based on scale, type of operation and future use.

Using the Government guidance LAQM TG4 (00) 'Review and Assessment: Pollutant Specific Guidance', a series of criteria were systematically considered in order to assess whether the processes are significant in terms of their impact on current and future air quality.

At Stage 2 a more detailed inventory was made of those pollutants (and their sources) which were identified as significant during Stage 1. Using simple, paper based screening models, ground level concentrations from a combination of background, road transport, industrial and urban sources were estimated for the current year and the objective year. This information was used to evaluate the potential effect of the pollutants on nearby sensitive receptors. Extra-sensitive receptors were identified at this stage, such as schools, nursing homes and hospitals. The models used were the Environment Agency's 'Guidance for Estimating the Air Quality Impact of Stationary Sources (GSS) and the DETR's 'Design Manual for Roads and Bridges' (DMRB).

At Stage 3, the Review and Assessment procedure has involved the use of more sophisticated methods of assessment in order to determine specifically the risk of exceeding air quality standards and objectives and the geographical extent of any exceedence. Conclusions drawn from the Stage 3 assessment are strongly validated.

Results of the review and assessment

• The Review and Assessment identified that background levels of all seven of the local pollutants of concern will fall over the review period.
• At the initial stages of the Review and Assessment process, it was concluded that levels of:
  • Carbon monoxide (CO)
  • Benzene
  • 1,3-Butadeine
  • Lead (Pb)
  did not pose a significant risk of exceeding the air quality objectives at any location.
• The second stage review and assessment identified the following areas, pollutants, and processes requiring further investigation.
• PM₁₀ levels from Bayston Hill Quarry, Shrewsbury
• NO₂ levels along significant road sections and junctions within the study area including the M54, A442, A518 and the A5
• SO₂ levels from two Part B processes (Glynwed Consumer Products and Berwyn Granite Quarries) in Telford and Wrekin and two large boilers, also in Telford and Wrekin.
• Emissions of PM₁₀, NO_2, and SO_2, from Ironbridge Power Station
• At the 3^rd stage of Review and Assessment, it was concluded that PM₁₀ levels were not predicted to be above the Air Quality Objectives at any location within the study area.
• The 3^rd stage of the review and Assessment revealed that of the two large boilers identified in stage 2 The Princess Royal Hospital boiler is to be converted to gas by 2005 and Crudgington Dairy Crest Creamery only use their oil-fired boiler as an emergency standby. The Company's records indicate that the oil-fired boiler has only been in operation for one day during the last three years. Accordingly an exceedence of the Air Quality Objectives from either of these sources is unlikely.

Ironbridge Power Station

• By 2005, it is considered extremely unlikely that emissions of Nitrogen Dioxide and PM₁₀ from Ironbridge power station as a single source will cause a breach of the air quality objective at any location within the study area. In addition, the power station will only have a minimal effect when combined with other sources of NO₂ and PM₁₀ within the study area, and thus no breaches of the Air Quality Objectives for NO₂ and PM₁₀ are considered likely from this source.
• Modelled emissions of SO₂ from Ironbridge Power Station based on likely operational parameters in 2005 indicate that the 15 minute air quality standard for SO₂ will be breached on a number of occasions, however the modelled results indicate compliance with the Air Quality Objective which permits up to 35 annual exceedences of this standard.
• Ironbridge Power Station is a Part A Process, authorised by the Environment Agency. The stations conditions of operation, as stipulated by the Environment Agency, require that from 1 January 2005, it shall be operated in such a way that the power stations releases of Sulphur dioxide, oxides of Nitrogen and particulate matter (PM₁₀) alone will not result in the exceedence of the respective Air Quality Objectives.
• Complex dispersion modelling has indicated that there is unlikely to be an exceedence of the 2005 15 minute SO₂ objective from Coalbrookdale foundry at relevant locations even in combination with Ironbridge Power Station and that SO₂ from the foundry is only a minor contributor to the combined SO₂ levels.

Other sites

Complex dispersion modelling has indicated that for the "worst case" scenario there may be an exceedence of the air quality objective for Sulphur Dioxide outside the boundary of the Leaton Quarry site (Berwyn Granite) close to sensitive receptors. However it is concluded that considering the conservative factors used in the model it is unlikely that there will be an exceedence of the 15-minute average SO₂ objective at relevant locations even when allowing for uncertainty within the model predictions.

Traffic related pollution - Nitrogen Dioxide

Detailed dispersion modelling of the traffic contribution of Nitrogen dioxide has indicated likely exceedences of the annual objective for Nitrogen dioxide (NO₂) at a number of sites. Modelling has shown that the highest annual mean concentrations of NO₂ occur at the centre of the road. Concentrations are predicted to fall with increasing distance from the road's centre.

• Predictions of annual average NO₂ have shown that exceedences of the 1-hour objective are unlikely in the year 2005. The assessment has included model validation against monitored NO₂ data at a roadside location providing confidence in the results.

It is concluded that the Air Quality Objectives for Nitrogen Dioxide will be met across most of Shropshire with the exception of the following relevant locations adjacent to busy and/or congested roads where the modelling has predicted NO₂ levels very close to or over the Annual Mean Objective.

Locations where the Annual Mean NO2 Objective will not be met:

• Heathgates Public House (Residential) adjacent to Heathgates Roundabout, Shrewsbury
• 10 Residential Properties on the North West kerb of the A49 Bayston Hill between Sharpstones lane and Lyth Hill Road
• The Gate House adjacent to the A5(T) North Oswestry
• 4 Residential Properties at Wellington and The Rock, Telford Adjacent to the M54
• 2 Residential properties near the Gyratory between Brockton Way and Queensway in Brookside, Telford
• 2 Residential properties near Britannia Way, Opposite Sunny Bank, Telford