Analysis undertaken by Dearman has highlighted the environmental impact that transport refrigeration units could be having on the UK’s urban streets.

Transport refrigeration units are used to keep refrigerated vehicles cold and although they are generally diesel powered and there are thousands in operation in the UK, they are currently unregulated. As a result, transport refrigeration units are disproportionately polluting – emitting up to 29 times more potentially carcinogenic particulate matter than a modern Euro6 diesel truck engine.

Research into these often-overlooked polluters has highlighted the disproportionately damaging impact they could be having.

Key findings of Dearman’s research include:

• there are approximately 84,000 transport refrigeration units on the road in the UK
• refrigerated vehicles travel approximately 84.6 million km annually in London alone
• their refrigeration units emit up to the equivalent of 49,125 tonnes of CO2,163 tonnes of NOx and 22 tonnes of particulate matter onto London streets every year
• the CO2 emissions caused by transport refrigeration units in London every year could be equivalent to a family car driving 447 million km – that’s almost 2.4million laps around the M25 or 11,200 times around the world
• if all transport refrigeration units in London could be made zero emission, then it would save the same  amount of particulate matter as taking 327,510 diesel cars off the city’s streets

Tim Fox, international ambassador at Dearman, and fellow of the IMechE said: “Until now, nobody has given transport refrigeration units a thought. We all shop at food stores, eat in restaurants or have chilled food delivered, but the impact of transport refrigeration units has never been investigated, let alone addressed.

“Although refrigerated vehicles make up a small proportion of the vehicles on the road, they are unregulated, use out-dated fossil fuelled technology and are disproportionately polluting. What’s worse, that pollution is concentrated on city streets where it does the most damage to our health.

“Rightly, there has been increased attention paid to the air quality in our cities. But this hidden polluter continues to be ignored. That has to change.

“In addition to continued investment to make diesel cars and trucks less polluting, we could make a sizeable impact on both NOx and PM pollution by bringing transport refrigeration units up to modern emissions standards – or even better making them zero emission. That small change could have a very big impact.”

The Dearman transport refrigeration system is currently undergoing on-vehicle trials, will enter commercial trials later this year, and will begin multi-country trials next year.