NOxBUSTER® City retrofit system

Proventia offers proven solutions for ULEZ and CAZ NOx reduction retrofit programs. The Proventia NOxBUSTER® City is a retrofit solution, which enables Euro III, IV or V buses and trucks to meet Euro VI emission standards. The systems have full TfL and CVRAS approval ensuring compliance with the Ultra Low Emission Zone (ULEZ) and Clean Air Zones across the UK. Over 1,400 systems have been installed across all major London bus operators.

Reliable and Robust NOxBUSTER®

NOxBUSTER® City DPF SCR systems enable heavy diesel vehicles to be upgraded to the Euro VI emission level. Thanks to Proventia’s specialized urea mixing and thermal management technologies, NOxBUSTER® City systems achieve high NOx and NO2 reductions even at low exhaust temperatures even in real city traffic. No additional heating devices or components are required.

The systems designed by Proventia for demanding OEM applications underpin the design and technology in their retrofit systems. This dedication to constant improvement and development allows our retrofit customers the chance to take advantage of the latest technological innovations. Proventia systems also feature the PROCARE™ Drive telematics system for continuous monitoring and reporting that provides real-time information on NOx emissions and EAT system purification performance online 24/7.

Why NOxBUSTER® City?

  • Proven to work in slow urban driving
  • High NOx reduction rates at low exhaust temperatures (below 200°C) and cold weather conditions
  • Proven results over the Millbrook MLTB, LowCVP UK Bus (LUB), Coach (LUC), HGV and RCV Cycle
  • Proven results in PEMS tests from an independent test laboratory
  • No additional heating devices or components required
  • Optimised urea mixing technology enables urea injection at low temperatures – no deposits
  • Advanced insulation technology maintains heat inside the system and improves SCR operation
  • Low surface temperature, no risk to other sensitive engine parts
  • Direct fit designs available for buses, coaches and RCVs
    Easy installation and maintenance


Approvals in the UK

Proventia have approved systems for following vehicles:


Engine make Engine model Displacement Vehicle examples
Cummins ISBe 4.5 4.5l ADL E200, ADL E400H, Wrightbus Streetlite, Optare Solo
Cummins ISBe 6.7 6.7l ADL E400, Wrightbus DB300
Volvo D9B 9.4l Volvo B9TL
Volvo D5F 4.8l Volvo B5H
Volvo D7C 7.3l Volvo B7RLE, Volvo B7TL
Volvo D7E 7.1l Volvo B7RLE, Volvo B7TL
Mercedes-Benz OM904 4,25l Optare Solo
Mercedes-Benz OM906LA 6.4l Citaro
Mercedes-Benz OM926LA 7.2l Citaro
Mercedes-Benz OM457LA 12.0l Citaro


Engine make Engine model Displacement Vehicle examples
DAF Paccar PR 8.2l  Temsa Safari, VDL Bova, Irizar i6
DAF Paccar MX 12,9l Temsa Safari, Irizar i6, Irizar PB, VDL Futura FHD2, Van Hool T9, TX & Astromega, VDL Bova Magiq & Synergy
Volvo D13 12,8l Volvo B13R chassis
Volvo D12 12,1l Volvo B12R chassis
Volvo D9 9,4l Volvo B9R chassis
Volvo D7 7,3l Volvo B7R chassis
Volvo F7 7,1l Volvo B7R chassis
Cummins ISBe 6.7 6.7l King Long XMQ6900
Mercedes-Benz OM457LA 12,0l Mercedes Benz Integro, Travego, Tourismo
Setra S415/S416/S417 GT and GT-HD
Scania DC9 8,9l Irizar PB/ Century, Scania OmniExpress, Caetano Levante
Scania DC9 9,3l Irizar PB/ Century, Scania OmniExpress, Caetano Levante
Scania DC12 12,7l Irizar PB/ Century, Scania OmniExpress, Caetano Levante
Scania DC13 12,7l Irizar PB/ Century, Scania OmniExpress, Caetano Levante

Truck (HGV)

Engine make Engine model Displacement Vehicle examples
Mercedes-Benz OM904 4,25l Mercedes Benz Atego & Unimog
Mercedes-Benz OM906LA 6.4l MB Atego & Axor
Mercedes-Benz OM926LA 7.2l MB Axor
Volvo D7 7.1l Volvo FL, Volvo FE, Renault Midlum & Premium
Volvo D13 13l Volvo FMX, Volvo FM, Volvo FH, Renault Premium, Renault Magnum, Renault Kerax
Volvo D16 16l Volvo FH
DAF Paccar GR 6,7l DAF LF55 &CF65
DAF Paccar PR 8,2l DAF CF75
DAF Paccar MX 12,9l DAF CF85 &XF105
Coming soon      
DAF Paccar FR 4,5l DAF LF45 & LF55

Refuse Collection Vehicle (RCV)

Engine make Engine model Displacement Vehicle examples
Mercedes-Benz OM906LA 6.4l MB Econic
Volvo D7C&E 7.3l&7.1l Dennis Eagle Elite

PROCARE™ Drive telematics

The Proventia PROCARE™ Drive is an advanced in-service NOx monitoring and reporting system. The on-board diagnostic system monitors the NOxBUSTER® system, the NOx emissions, urea level and DPF back pressure. The PROCARE™ Drive online portal system provides real time data on the whole fleet and enables early identification of any possible performance issues or maintenance needs.

Installation and service

Proventia’s UK partner, Excalibre Technologies, has a team of highly skilled, locally based technicians to install and maintain the systems with 24-hour availability for all customers. After installation Excalibre Technologies provides a comprehensive service and maintenance program including DPF cleaning. We also have a local UK stock holding for spare parts, which ensures a fast and efficient replacement service available throughout the year.

Our representative in the UK


Excalibre Technologies Ltd

Building 6,
Vantage Point Business Village
Gloucestershire, GL17 0DD
United Kingdom

Tel. 44 (0)1594 887414
sales (at)