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Reducing Air Pollution In Dudley’s Environment

A Project Supported by the Government’s Clean Vehicle Technology Fund

In 2014 Dudley Council in conjunction with Prospect Coaches, one of the main transport providers for Dudley schools and colleges, applied for and received a grant of £158,000 from the Department of Transport. The funding has been used to reduce emissions from 10 of Prospect’s coaches (7 Euro III coaches and 3 Euro II coaches).

The coaches have been modified to incorporate the latest pollution reducing equipment, Selective Catalytic Reduction and Particle Trap (SCRT), reducing emissions of nitrogen oxides (NOx) and particulate matter (PM) to levels comparable with the latest vehicle specifications, thereby benefitting both the local environment and the health of Dudley residents.

The modifications were completed in September 2015 and upon commissioning emissions from each coach were monitored for nitrogen oxides. Further monitoring of 4 of the coaches took place six and twelve months after commissioning. Each vehicle was tested on the same route twice, allowing results to be obtained with changing road conditions and driving styles, over an agreed typical route used by the coaches in the Borough. The route measured 14.9km, starting on Auckland Road and finishing near Halesowen College. To ensure testing conditions represented real world circumstances all usual coach stops were implemented with a wait time of around 15 - 20 seconds. However the coaches were empty and therefore the load was not representative.

Nitrogen oxides sensor data obtained from each vehicle was used with GPS data taken from each route along with vehicle odometer readings to calculate emissions per kilometre.

The monitoring indicated a significant reduction in emissions, the typical average percentage reduction for NOx for the coaches is provided below;

Euro III
At fitment – 99% Reduction in NOx
At 6 Month – 97% Reduction in NOx
At 12 Month – 97% Reduction in NOx

Euro II
At fitment – 98% Reduction in NOx
At 6 Month – 70% Reduction in NOx
At 12 Month –80% Reduction in NOx

The aim of the project was to achieve a 90% reduction in NOx emissions. The SCRT has worked well for the Euro III coaches with results for NOx reduction consistently achieving 97% or more, however the Euro II coaches have not performed so well, this is attributed to Euro III higher exhaust gas temperatures. From analysis of the data the Euro II emission reduction performance will be greatly increased with added vehicle weight (i.e. passengers) increasing engine load which in turn results in higher exhaust gas temperatures allowing the SCRT to be more effective.

The reduction in emission of particulate matter has been calculated using data from testing of similar vehicles at Milbrook Vehicle Testing Station and the mileage of the 10 coaches over the 12 months since the retrofit was completed. The calculation has indicated a reduction of 98% leading to a reduction of 0.6 tonnes of particulate matter being released to the atmosphere in the 12 month period.

The retrofits were completed in August 2015 and several of the coaches pass the DMBC air quality monitoring station at Colley Gate, frequently every day. The table below shows the improvements to date The particulate matter has shown a significant improvement however the Nitrogen dioxide data has shown an increase in level for 2016. The level of nitrogen dioxide can be influenced by weather conditions and therefore a trend over several years needs to be established to fully assess the impact of the measures.

Nitrogen Dioxide Year on Year Levels

Year Nitrogen Dioxide µg/m3 Particulate matter PM10 µg/m3
2014 35.5 21.7
2015 34.9 21.9
2016 39.0 19.0

The modifications to the coaches cannot be considered in isolation as another project to improve the traffic flow in this area has recently been completed but it can be considered a successful contributory factor in improving air quality in and around the borough of Dudley.

Contact Details

Environmental Safety and Health
People Directorate
3-5 St James's Road

Telephone: 0300 555 2345

Opening Hours: Monday to Friday, 8.45am to 5.00pm
Offices are closed at weekends and Bank Holidays.