Low emission zones and stricter vehicle emission standards have led to marked improvements in urban air quality – but beyond road traffic, non-road mobile machinery used for construction remains an important source of air pollution in cities. 

Hydrogen could play a key role in cutting air pollution from the construction industry. With hydrogen forecast to make up as much as 20–35% of the UK’s final energy consumption by 2050, end-use applications include industry, power, heating, and crucially, non-road machinery.

One promising innovation is the hydrogen internal combustion engine, also known as H2ICE, particularly for use in heavy-duty and off-grid environments. These settings often demand high power outputs over long hours, which means full electrification using batteries can be challenging due to limited or no grid access and demanding load cycles.

While hydrogen combustion has traditionally posed challenges, including high flame temperatures that increased emissions of nitrogen oxides (NO_x), advances in engine design are now addressing this. 

“A 4-cylinder, 55 kW spark ignition hydrogen engine using lean-burn combustion has demonstrated consistently low emissions of nitrogen oxides across a range of off-road work cycles. In fact, NO_x emissions were found to be 40 – 500 times lower than those from state-of-the-art diesel engines. The emissions coming directly from hydrogen engines are so low, some H2ICE vehicles may not need complex exhaust aftertreatment systems such as Selective Catalytic Reduction. 

“H2ICE may be particularly beneficial for densely populated urban areas and major infrastructure sites where air quality effects are considered as part of planning approvals,” explains Professor Ally Lewis, atmospheric chemist at the National Centre for Atmospheric Science and University of York.

The UK Department for Transport has recently approved H2ICE for on-road use, and JCB has launched a hydrogen-powered backhoe loader. The forthcoming £6.5 billion Lower Thames Crossing project has even specified the use of hydrogen-powered equipment for work on site.

Ally Lewis describes how JCB, one of the world’s top three manufacturers of construction equipment, are working with researchers to understand the air pollution emissions from their engines:

“JCB has invested more than £100M in the development of hydrogen technology for construction equipment. By sharing test data with the National Centre for Atmospheric Science and the University of York, JCB are working closely with air quality researchers to understand the potential benefits of different engines and exhaust aftertreatment systems. We’ve been able to independently verify emissions performance at different engine, power, and torque settings.

“The results of our research have been shared with JCB and made publicly available to inform other manufacturers, like Cummins and Volvo, who are developing hydrogen engines too.” 

Air quality experts from the National Centre for Atmospheric Science, like Professor Ally Lewis, have also joined an industry-led group that reports to the UK Government’s Department for Energy Security and Net Zero, to explore the construction industry’s opportunities for H2ICE and discuss the benefits for the environment and to UK manufacturing. 

As the UK works toward its net zero goals, low-emission hydrogen combustion engines offer a practical and impactful route to reducing construction-related air pollution, and improving air quality where it matters most. 

Researchers at the National Centre for Atmospheric Science are investigating how national investments in decarbonisation can improve the quality of the air we breathe, and as a co-benefit, our health. 

“Critically, we are also identifying where net zero and air quality might be in tension. For example, our evidence for the potential negative air quality impacts of using hydrogen for home heating was cited by the National Infrastructure Commission in 2023, where they ultimately recommended against hydrogen use for that application,” adds Ally Lewis.