About Us

HJS Emission Technology was founded in 1976 with its headquarters based in Menden, Central Germany.   HJS employs approximately 400 people who are engaged in the development, production and marketing of modular exhaust systems for reducing emissions for all road, rail, construction and marine applications.


Our business in the UK is supported by our dedicated sales, project management and technical teams operating from our facility in Bracknell, Berkshire.  From this facility, our engineering team provide nationwide installation and technical support.

The reduction of Nitrogen Oxides (NOx) contributing to air pollution is one of the most challenging public health issues facing the UK today.  Diesel exhaust emissions have been classified as carcinogenic to humans, reassigning it to the same class of hazardous materials as asbestos, arsenic and mustard gas.  The majority of urban areas in the UK are struggling to meet stringent European requirements for NOx emissions and the government has been ordered by the Supreme Court to take action in the quickest time possible.

HJS work together with bus/coach operators and local authorities to improve air quality across the country.  HJS are the pioneers of Selective Catalytic Reduction Technology (SCRT®) which can be retrofitted to significantly reduce NOx emissions and also virtually eliminate particulate matter.  The HJS Real Blue SCRT® system meets Euro VI standards and is both ULEZ and CAZ compliant. System performance has been certified at Millbrook Proving Ground which has been followed up by several months of successful in service testing.

In 2019, Transport for London will introduce a 24/7 Ultra Low Emission Zone (ULEZ) to improve the problem of urban air quality in the capital.  In addition to this Birmingham, Nottingham, Derby, Southampton and Leeds will be introducing Clean Air Zones (CAZ’s). 28 more cities and towns have also been identified requiring additional measures and Glasgow will become Scotland’s first Low Emission Zone at the end of 2018.

The HJS Real Blue SCRT® system is accredited by the Energy Saving Trust’s CVRAS (Clean Vehicle Reduction Technology Scheme). Our approved technology allows vehicles to be upgraded to meet LEZ, ULEZ and CAZ requirements and complies with the conditions set out within the Clean Bus Technology Fund (CBTF).



For over 40 years, HJS has established itself as an innovative company with national and international benchmarks for the automotive industry.Continue reading »


HJS has been developing technologies for environmentally friendly mobility as the basis for a clean future since the 1980s.Continue reading »


Our project and infrastructure enables flexible and individual implementation of projects at attractive costs.Continue reading »


We owe our business success not only to the high quality of our products and processes, but also to their continuous improvement.Continue reading »

Our Mission zero emissions


The Greater London Authority Low Emission Zone for Non Road Mobile Machinery  

The Low Emission Zone in London applies to all Non Road Mobile Machinery (NRMM) with a net power rating of between 37kw and 560kw operating within central London.

The minimum emission standards for NRMM within London are detailed below:

  • NRMM used on the site of any major development, as defined in the London Plan within Greater London will be required to meet emission Stage 3A as a minimum

  • NRMM used on any site within the Central Activity Zone or Canary Wharf will be required to meet emission Stage 3B as a minimum

  • All eligible NRMM should meet the standards above unless it can be demonstrated that a comprehensive retrofit to meet both PM and NOx emission standards is not feasible. In this situation every effort should be made to use the least polluting equipment available including retrofitting technologies to reduce particulate matter emissions

Central Activity Zone or Canary Wharf Greater London
From Sept 2020 Stage IV or best available retrofit technology Stage IIIB or best available retrofit technology 

With an estimated 10,000 active construction sites in London at any one time NRMM has been identified as one of the largest contributors to poor air quality in London.

Plant hire companies machine operators and construction organisations have the following compliance options:-

  • Retrofit existing machines with emission abatement technologies

  • Reorganise NRMM fleet to ensure compliant equipment is used

  • Replace or re-engine equipment

For the majority of operators the retrofitting of existing machinery will be the quickest, most effective and most reliable way of ensuring that they comply with the conditions set within the LEZ.

To find out more visit the energy savings trust website :- Click Here


HJS have installed thousands of emission abatement systems throughout the UK and Europe.  These systems require regular servicing and maintenance in order to ensure efficient operation and maximum reliability.  HJS’s dedicated team of specialist technicians can offer the full service and maintenance packages and more.  Packages can be tailored to suit the requirements of our customers.

Our engineers are also able to troubleshoot and help diagnose vehicle issues which are reducing system servicing intervals.

To discuss your servicing options give us a call today on 01344 566050

Contact Us

Emission Engineering Ltd
9 Sterling Centre
Eastern Road
RG12 2PW


Office: 01344 566 050

Mark Cooper
Managing Director
07733 227889

James Salmon
Technical Project Manager
07736 148 346

Gerd van Aaken
07949 123 361


Our partner:

Cybrand AEC Ltd
Phone 0151 343 3199

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