Bi-mode trains and electric car batteries criticised in clean air report

Engineers concerned about transport emissions want policymakers to spearhead a rollout of new monitoring equipment across swathes of streets, stations, ports and airports to gather the best data on pollution and precisely target mitigation efforts at the worst offenders.

Their report suggests on-vehicle monitoring devices should be fitted to some cars to harvest real-time data on tailpipe emissions of pollutants, for example the various oxides of nitrogen, and calls for incentives to be created to encourage freight deliveries to be carried out outside of peak hours.

A Breath of Fresh Air: New Solutions to Reduce Transport Emissions, published by the Institution of Mechanical Engineers (IMechE), recommends the introduction of a coherent scheme to monitor emissions from different forms of transport so informed targets can be set.

Reliance on so-called bi-mode trains on parts of the rail network comes in for flak in the report, whose lead author, Philippa Oldham, works at the Advanced Propulsion Centre, an organisation involved in low-carbon technologies.

“A bi-mode intercity train is effectively a more expensive, heavier and less reliable electric train, or a more expensive, under-powered diesel train,” the report states, before warning that investment in diesel-fuelled kit is undermining the business case for rail electrification.

Oldham said a government-backed push, akin to efforts to encourage people to quit smoking, was now needed to push the travelling public towards “modal shift” - e.g. switching from cars to bicycles or walking. 

She questioned the sustainability of the much-vaunted electric vehicles, saying their batteries, many of which still use unethically sourced rare earth materials and which can be economically unviable for recycling or reuse, may store up problems for the future.

“We are seeing a lot of push towards electric vehicles, but we need to look at their whole lifespan,” Oldham told E&T. “Are we just lumbering the next generation with a whole load of problems, like we did with diesel, rather than looking at the bigger picture?”

Particle pollution from electric cars could eventually eclipse all other sources of transport-related pollution, air quality expert Professor Roy Harrison from the University of Birmingham has previously suggested.

However, the vehicles are widely regarded as bringing benefits as they produce zero air pollution emissions from their tailpipes.

“The work being championed by government in switching from internal combustion engines to electric vehicles will help reduce early deaths associated with air pollution, but it will do little to encourage greater physical activity,” the IMechE report states.

Sadiq Khan, the Mayor of London, last year introduced a toxicity charge tax as part of his plan to curb dangerous air.

Oldham believes that, rather than going into the general coffers of City Hall, the money generated from this tax should be put towards funding anti-toxicity measures like installing particle-absorbing bamboo plants and peace lilies inside classrooms in parts of inner London lumbered with the dirtiest air.

Better data is needed on London Underground commuters’ exposure to pollution is needed, she added. 

The report states: “We recognise that road transportation accounts for a vast majority of pollution, but this does not relieve the rail industry of its responsibilities. While London Underground makes use of electric trains, these can cause pollution with damaging implications for health – for example metal-rich UFP [ultra fine particles] from brake linings and friction between wheel and rail. In 2017, research from the University of Surrey found concentrations of PM [particulate matter] became much higher from the moment that the commuter gets inside the underground station.”

Transport for London (TfL) insists levels of particulate matter on the Tube network are safe and remain well below the limit set by the Health and Safety Executive.

E&T last year revealed TfL had spent more than £6.5 million acquiring a special tunnel-cleaning project that was later ditched amid suggestions that mobile units being used to hoover up dust were also pulling asbestos out of the lining of tunnel walls.

Air pollution is said to be responsible for one in 10 of all deaths globally. The IMechE report cites cruise ships as a growing source and recommends local authorities insist on “shore-to-ship” technology to power docked vessels and thereby prevent pumping out harmful gases while sitting idle.

Meanwhile, retrofitting solutions advanced for “legacy” road vehicles include switching to liquid nitrogen-fuelled engines or fitting tiny hoover-like devices around car wheels to suck up harmful black carbon emitted from tyres.