From highways to harbours, reduced emissions are improving air quality

William Bonnell, Transport Systems Engineer, and Robin Koerner, Transport Systems Engineer at Energy Systems Catapult discuss the subject of air pollution and the work that is being done in the highways and harbours sectors to decarbonise fleets and ports and the impact that this is having.

Reducing emissions and improving the quality of the air we breathe is crucial to improving the overall health of people in the UK. Yet, despite what we know about the link between air quality and health, we need to accelerate efforts to improve air quality.

Research has shown that existing air pollution regulations could prevent 6,751 early deaths by 2030. In 2022 over 95% of residential addresses in the UK exceeded the World Health Organisation limits for one of three main pollutants.These include nitrogen dioxide (NO2) and two grades of particulate matter (PM). These are PM10 and PM2.5 which are particles that have a diameter of about 10 and 2.5 micrometres respectively. Other nitrogen and oxygen compounds also contribute to air pollution, called NOx pollutants. 

We are moving in the right direction with air pollution emissions decreasing steadily in recent decades. A classic example of this is in transport with regulations on vehicle emissions and policies such as emission charges. More can – and should – be done to accelerate the reduction of emissions to safeguard lives.

An assessment of air quality provides another lens to examine the work that is ongoing to accelerate Net Zero energy innovation. Solving this problem requires us to think outside the box to tackle head-on emissions from hard-to-abate sectors: freight and maritime. 

Road freight 

It is common knowledge that road freight and transportation is a major contributor to UK air pollution. Burning fuel, especially diesel, in road vehicles accounted for just under a third of all UK NOx emissions in 2021. They were also a significant contributor to particulate matter pollution, accounting for 14% of PM2.5 and 12% of PM10 emissions. Some of this particulate matter comes from vehicle engines, but another major source is the result of brake pads and tyres wearing down.  

To improve air quality, we need to enable the production and use of low emissions heavy goods vehicles (HGVs). HGVs are more polluting than smaller vehicles like cars, producing 21kT of NOx pollution in 2021, about 11% of the total road transport emissions. This is despite HGVs only accounting for 6% of the total miles driven. In other words, HGVs are more polluting on a per-mile basis than the more numerous smaller vehicles on the road. This effect is even greater for CO2 where HGVs account for 20% of road transport emissions. 

Smaller cars and vans produce more air pollution overall because there are more of them. However, many of those journeys can be replaced by personal zero emission vehicles, active travel (e.g. walking or cycling), or public transport. These replacement journeys can then be further encouraged with appropriate planning or policy. This is much harder to do with HGVs where fewer alternatives are plausible. To improve air quality then it is vital that we transition away from legacy trucks which burn diesel to those powered by electricity (eHGVs) or hydrogen.

The eFREIGHT 2030 consortium – led by Voltempo and including members such as the Catapult, Kuehne+Nagel (UK) Limited, Wincanton Group Limited, and Maritime Transport Limited – can help enable the transition by demonstrating the abilities of these new, low-emission HGVs. The project will do this by introducing 100 electric HGV 4×2 and 6×2 tractor units, and 32 new charging locations, all of which will have megawatt-charging capacity from day one. 

The Catapult will also explore how the transition can be accelerated. We will do this with national-scale modelling that will explore how different scenarios affect the new HGV market. We will also consider what infrastructure we need to support it. The results of this modelling and the five-year trial can then be combined to provide a clear path for transitioning to low-emission HGVs. 

Getting to Net Zero is not a nice to have. It is a necessity. Not only will it deliver better environmental outcomes, but it can help improve the health of the nation. Importantly, reducing emissions from freight can benefit those living in suburban and urban areas, typically the worst affected by road transport air pollution. We can therefore be hopeful that projects like eFREIGHT 2030 can help further reduce air pollution and provide the clean air we deserve.

Maritime and ports 

Ports and the maritime sector are significant contributors to air pollution. In 2016, domestic shipping in the UK accounted for 10% of the country’s total domestic NOx emissions, 2% of primary PM2.5, and 7% of SO2 emissions. However, these figures exclude emissions from international ships visiting UK ports, indicating an even broader impact.

The industry is undergoing significant changes to reduce air pollution. In 2020, stricter global limits on the sulphur content of fuel came into effect. In England, major ports are developing air quality strategies aimed at mitigating emissions from port operations. This effort aligns with the broader Clean Air Strategy, which emphasises the need to reduce emissions across ports and associated waterways, including those from shore activities and visiting ships. The government is also reviewing the expansion of Emission Control Areas (ECAs) in UK waters, highlighting a commitment to minimising the maritime sector’s environmental and public health impacts.

To tackle these challenges, the Clean Air Strategy requests larger English ports to establish Port Air Quality Strategies (PAQS), to provide a clear understanding of air quality issues within ports and outline actions to address emissions under port control. Although port operators may not directly influence emissions from all ships, especially those adhering to international regulations, they can still implement measures to mitigate their own operational impacts, such as managing their vehicle fleets or improving cargo handling efficiency.

Projects like Port of Aberdeen Shore Power Technologies, as part of the Zero Emission Vessels and Infrastructure (ZEVI) competition, showcase the collaborative efforts from Energy Systems Catapult to address these challenges.  The Decarbonisation Roadmap and Assessment Framework created in this project will highlight the importance of air quality, especially in urban-centred ports like Aberdeen North Harbour. These initiatives not only drive environmental benefits but also provide social value by ensuring cleaner air for surrounding communities.

Hand-in-hand

Air quality and Net Zero go hand-in-hand. Getting to Net Zero will improve our air quality, improving our air quality can take us to Net Zero. You can’t have one without the other. Improving air quality clearly provides us with another way to frame our work at the Catapult. Projects like those mentioned above aim to help accelerate Net Zero. If successful, they will also help reduce air pollution caused by the transport sector. 

Image of authors courtesy of Energy Systems Catapult.