Refuse trucks in Westminster are to be fitted with technology which cut nitrogen dioxide emissions by 99% during a recent trial.

The solution replaces existing exhaust systems and filters emissions of the heavy-duty diesel vehicles.

The technology, developed by Eminox in partnership with Westminster City Council and Veolia, was trialled on two of the local authority’s Euro 5 refuse collection vehicles.

During the pilot, nitrogen oxide levels fell by 99%, resulting in lower emissions than newer Euro 6 vehicles which means they also beat the ultra low emission zones (ULEZ) target set by Transport for London.

Tim Mitchell, cabinet member for environment and city management for Westminster City Council, said: “Poor air quality is a major concern for our residents – that’s why we’re using new technology to tackle the problem in a world first.

“Westminster is a leader in improving air quality and councils across the UK have eagerly followed the project’s progress. Investing in technologies like this scheme is how we’re creating a healthier and greener city.”

Eminox designed the technology after Westminster City Council committed to retrofitting its vehicles with the invention, should it be successfully accredited under the Clean Vehicle and Retrofit Accreditation Scheme (CVRAS) for ULEZ.

The trial included lab testing as well as field testing on the two Westminster vehicles, which resulted in the Eminox SCR & PM Abatement System with ASDS technology receiving accreditation by Energy Saving Trust and CVRAS.

This accreditation formally recognises the system as a solution to reach clean air targets.

The two Westminster City Council vehicles used in the trial will continue to run with the installed system, while the remainder of the fleet will be fitted ahead of ULEZ starting in April 2019.

The system works by combining a diesel particulate filter with selective catalytic reduction and Amminex ASDS technology.