Monday, 10 January 2011

Don't let science get in the way of a good policy

So says one Ray Pawson in the Journal of the Canadian Medical Association and reported here. This English-educated high flier in sociology concludes that although there is too much complex evidence to come to a sure conclusion about the level of exposure and the harm it will do, there is enough evidence to warrant the passing of legislation to prevent anyone from smoking in a car with a child in it.

A further account goes as follows:
While trying to determine the risks involved, the authors first looked at the mixture of chemicals that make up second-hand smoke and its concentration in cars under different conditions such as volume, speed and ventilation. Second, they looked at how long a person would be in the car. Third, they observed how long a person would be exposed to the second-hand smoke. Fourth, the extent of difference between how second-hand smoke affects children compared to adults was added to the risk equation and finally, the authors looked at the health impact, which is hard to determine because of all the different chemicals and toxins a person is exposed to in their lifetime.
I can't find much in the composition of smoke to get excited about: the diagram shows that smoke is about 90 per cent air and about 10 per cent a combination of other gases (further discussion here if you're interested). The account continues:
"Policy based on science and evidence has to exist amid uncertainty and this is managed by acknowledging the contingencies," write the authors. "Thus, i) because of the confirmed [confined?] cabin space, and ii) under the worst ventilation conditions, and iii) in terms of peak contamination, the evidence permits us to say that smoking in cars generates fine particulate concentrations that are, iv) very rarely experienced in the realm of air-quality studies, and that will thus constitute a significant health risk because, v) exposure to smoking in cars is still commonplace , and vi) children are particularly susceptible and vii) are open to further contamination if their parents are smokers."
 In the absence of any evidence on the smoke exposure levels in any individual car but taking a worst-case scenario, the authors attempt to pass this off as 'science', and use it to justify a policy that prohibits smoking in cars. They are correct (if this table is to be believed) that particulates of smoke are exceptionally fine (although the word 'concentrations' puzzles me as this depends entirely on the amount of smoking and air exchange). But calling this approach 'policy based on science and evidence' is taking the mick, when they're also saying that actual evidence isn't necessary.

I can't help feeling that the anti-smoking campaign did things the wrong way round if it wanted to convince us that it cares about children. First it went for smoking in the workplace and in pubs, in spite of warnings that people would smoke more at home. The rationale was to protect the workers. Only having achieved this did it start on protecting children in private spaces, with some local authorities prohibiting foster carers from smoking at home (claiming a stake in the shape of the children's health) and now cars are under discussion.

A policy based on children's health would have gone all out to make the claims about children first. This didn't happen because it would have meant an immediate intrusion on private space. The way it was done was the politically acceptable way: it has meant gazillions of car journeys have taken place in the meantime with children fully exposed to secondary smoke.

Not that I think it's done them any damage, or the ones exposed to smoke from their foster parents. If there is a genuine health issue many parents will respond to it by controlling smoke, but why disempower people with this 'no safe level of secondary smoke' nonsense?

If it comes to it, there's no safe level of anything.


The witch from Essex said...

I would rather see a child in a car with the windows shut with someone smoking than no smoking in the car with the windows open.
The amount of cancer causing chemicals on the public road being spewed out from exhausts is frightening.
Try putting someone in a car with a smoker for 10 minutes and see the difference as someone in a car with exhaust pipe fumes/ The difference is that ONE of them will be dead !!

Anonymous said...

Nicely put, "Witch from Essex"!

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Anonymous said...

I'm reminded of the famous HSE report that admitted they could find no link between second hand smoke and specific diseases. An anti smoker pointed out that the report concluded that the only way to ensure no bar staff were harmed by SHS was to ban smoking in bars.
I found this bizarre, there is no risk found, and the only way to obviate any risk is to ban smoking in bars!
One might as well say 'There is no evidence of fairies at the bottom of the garden...The only way to ensure that no fairies are harmed is to ban lawn mowing'!
This is Michael!