Back in the early eighties I remember New Scientist warning that government policy of promoting diesel engines over petrol, because diesel engines used less fuel thus prolonging the life of existing oil supplies, would result in increased cases of respiratory disease because diesels were dirtier, their emissions being particularly nasty because they featured particulates small enough to go where few other particulates could go.
And that, further, touted "improvements" in diesel engine design would certainly improve their performance to equal petrol engines (back in the 80's diesel engines were mostly restricted to use in lorries and tractors) by increasing compression ratios. Unfortunately, as NS pointed out, this would also serve to increase the efficiency of particulates in penetrating even further into those areas they could do a lot of damage in, the particulates having been smashed into even smaller particles, enabling them to boldly go where no particle had gone before!
Interesting spotlight on government priorities there.
And does anyone remember the Esther Rantzen programme 'That's Life'? Remember the one that featured the introduction of child buggies where the kid sat facing forward? Remember why this was picked up on as being inestimably stupid?
How high off the ground is a car exhaust?
Which side of the car does the exhaust usually emerge from under the car in the UK?
Whichever side of the car it emerges, where are all the exhaust gases going to be hanging around above the road?
How high is the kid's head above the ground? Or put another way, is the kid's head a lot lower than the person's pushing the buggy?
So which of the two is getting the biggest face full of exhaust gases?
Isn't life great?