The Welsh government wants to install 30ft high “air quality barriers” along a near half-mile stretch of the A494 in Deeside

The Welsh government intends to submit a planning application to install three 30ft high “air quality barriers” along a near half-mile stretch of the A494 in Deeside.

A request has been submitted to Flintshire Council planners for their views on whether the installation of timber barriers stretching from Aston Hill to Queensferry will need an Environmental Impact Assessment.

Air quality barriers have been tested in both the UK and Europe however, documents submitted to Flintshire planners by Cardiff based WSP planning consultancy state “no similar structures are currently in place.”

The barriers work by pushing vehicle emissions upwards to a height where they can mix with cleaner air, aiding dispersion of pollutants.

The section of road where the barriers are proposed to be installed has already been reduced to 50mph due to levels of Nitrogen Dioxide (NO₂) being above the legal limit as set out by an EU directive.

Average speed cameras have also been introduced along the east and westbound carriageway of the A494 to monitor the 50mph zone which stretches from St David’s Park, Ewloe to Deeside Industrial Park Interchange.

The aim of the barriers is to further safeguard those living close to the A494 and will “complement the already established reduced speed limit to further reduce roadside exposure to air pollution.” According to documents submitted to the council.

The addition of barriers presents a physical barrier to air movement reducing roadside exposure to pollution without actually reducing emissions.

“Installation of barriers would result in no net change in overall emissions, over and above what would be achieved through reducing the speed limit.”

However an assessment of the 50mph speed limit with the added impact of air quality barriers on the A494 has shown that roadside pollutant concentrations would be reduced by up 11%, according to the planning consultancy.

“Therefore, it is anticipated that the installation of the air quality barriers would have a positive contribution to air pollution.” Documents state.

The red line shows where the three sections of air quality barriers – the height of two double-decker buses – would be situated along the A494.

The proposed development comprises of three separate sites along the A494, each comprising solid fencing 9m in height across the entire length and “linked to the height of the nearest residential properties.”

The first section would run 430m from the exit of Old Aston Hill, adjacent to residential properties on Alder Avenue, down the hill ending at the Lower Aston Hall fly over.

A second section, 70m in length, would be installed from the flyover along the grass verge outside the Plough Pub.

If plans are progressed, a 200m third section will be installed from the Plough Lane junction along Aston Road to South Bank.

A 70m long 9m high solid fence could be installed on the grass verge outside the Plough Pub

The A494 would be visually blocked out for those properties where the barriers will be installed, one added bonus for residents, “due to the air quality barriers being solid in nature, they are likely to lead to a reduction in noise from the traffic.”

The WSP document says: “The barriers will potentially have a negative impact on natural views of the landscape.”

“However, as they would be situated within the existing transportation corridor, the overall impact is likely to be reduced as a result.”

“It is considered that the installation of barriers may impact on the view of journeys taken on road and footpath, however this will be for a limited time period as road users or pedestrians pass the barriers.”

“It is anticipated that the design of the air quality barriers will utilise timber as a building material, therefore reducing potential visual impacts with the use of natural materials.”

They also state that the “proposed development will not impact the function or operation of the carriageway.”

“In addition, it has been assumed that the air quality barriers should not have any further impact on the number nor severity of accidents.”

“Siting of the air quality barriers has been based on consideration as to where the barriers would have the most beneficial impact along the A494.”

“To facilitate the installation of the air quality barriers, the removal of trees present within the site may be required.”

“The clearance of vegetation on site will take place outside breeding bird season. If works must occur within the breeding bird season.”

In the event that air pollution levels are reduced below the maximum limits, “the air quality barriers may be removed; however, at this stage it cannot yet be determined how long this would take.”

A Screening Opinion Request is submitted to see if a development should be subject to an Environmental Impact Assessment, the aim is to identify projects that might have significant effects on the environment.

Abigail Huntley, Assistant Planner at WSP said: “We anticipate that the Proposed Development is unlikely to give rise to significant environmental effects during both the construction and operational phases.”

WSP say that the development “would not be significant such as to warrant the submission of a statutory EIA and the forthcoming planning application will be accompanied by appropriate reports in respect of technical matters to demonstrate the localised environmental effects of the proposed development will be acceptable.”