Dare I suggest this should mean a revisit of filthy DMUs left running in Birmingham New Street
Passengers won't be exposed to the particulates in the same way; it's the soot that contains the real nasties. Engineers cleaning soot from engines and exhausts should be careful, even if the engine isn't running.
But those who spend all day working there, and at Manchester Victoria, might want to consider things. The footbridge at Victoria is particularly disgusting.
On diesel fumes being carcinogenic, for what cancers? The cases being commented upon had (it seems) a huge range of tumours
There is strong evidence for mouth and lung cancers- the soot causes many issues- and some evidence for bladder and bowel cancers being caused by diesel fumes and soot.
It is easy to develop the "it stands to reason" arguments when often it does not.
It's certainly an amazing coincidence workers working with diesel fumes and soot get the cancers linked with diesel fumes and soot! It's like coal miners all having COPD and asbestos workers all getting cancer, just a random cluster!
I do agree that there is often more than one factor in play with cancer- hereditary predisposition as well as other environmental factors. If you smoke 40 a day and you're a diesel fitter, both environmental risk factors are in play. But that means both contribute; there can be more than one cause.
And yeah, kids living next to Sellafield all getting leukaemia too. Just a random cluster of randomness randomly clustering right next to a nuclear waste processing site with a sketchy safety record.