Tuesday 15 November 2011

Smoking in cars: groundhog day

Word has it that the British Medical Association is going to have another stab at campaigning for a smoking ban in cars today. This is turning into an biannual crusade and I don't have any more to say about it than I did in all these previous posts.

The chances are they will claim that a cigarette smoked in a car exposes passengers to either 23 or 27 times more secondhand smoke than they would get from a whole night in a smoky bar. Both of these statistics are obviously absurd. The "27 times" canard comes from an unpublished, non-peer-reviewed study presented at a conference nine years ago. It was heavily rigged towards getting the "right" result and finally concluded...

The calculated exposure for a five hour automobile trip with the windows closed/ventilation off and with a smoking rate of 2 cigarettes per hour is 25 times higher than the same exposure scenario in a residence.

"Residence" is not quite a "smoky bar" and "windows closed/ventilation off" is not exactly a realistic scenario for a smoker on a five hour car journey, but nevermind. And no, I don't know why 25 got changed to 27, but this is the reference ASH use for the claim.

The "23 times" claim is even more fun, because it involves a rare mea culpa from tobacco control. In a study in the Canadian Medical Association Journal entitled 'Second-hand smoke in cars: How did the “23 times more toxic” myth turn into fact?', MacKenzie and Freeman showed that the "fact" was entirely without scientific evidence and stemmed from a, obscure quote in a local newspaper in 1998 (as I had revealed on this blog two months earlier).

They concluded with the following unheeded recommendation:

We recommend that researchers and organizations stop using the 23 times more toxic factoid because there appears to be no evidence for it in the scientific literature.

I'll be talking about this on BBC Sussex at around 9.40 am.


Anonymous said...

Good luck Chris. I am on BBC Radio WM at 9.30, Radio BBC Stoke at 10.20 and Patsy Nurse BBC Radio Lincoln at 7.30 and 8.30.

Let's go and get 'em.

Dave Atherton

JJ said...

The interviews are coming thick and fast now for you two and Simon Clark.

Good luck to you all.

One thing interests me about the 23times more concentrated than a smoky bar routine. Have there ever been any scientific field or laboratory experiments carried out to validate this statement, which have then been peer-reviewed and published in any reputable scientific or medical journal?

Smoking Hot said...

l'm with JJ on this. Poo-pooing BMA's stats is not enough. An actual scientific study releasing all the data and results showing that BMA are talking crap would be the more intelligent and effective response.

Surely someone has done this and if not, why not?

Anonymous said...

I shall be 'going equipped' later in my car, armed with cigarettes and lighter.

Angry Exile said...

Chris, see The Daily Mash today. Should raise a smile.

John said...

I can barely type this I am so angry after listening to the Today programme, even when the presenter asked the 'doctor' if the 23 times claim was fact and peer reviewed she said yes and was allowed to get away with it. Simon was far too nice. I cannot listen to this non-science any more. Told my wife on the way to work I would go to prison before I stopped smoking in the car, she thinks I should put the family first, but I cannot take this any more, we need to stop this.

Anonymous said...

Sometimes it takes the madness to run at a fevered pitch and a point in time for the head to fly off and then its over!
I refer to the falling heads of the EU demise.

JJ said...

Sadly John you hit the nail on the head, Simon is just too nice and not robust enough to mix it even though he may have the knowledge.

He should have come straight back whether the presenter liked it or not, and asked.

“In which medical or scientific journal has it been published after peer-review and where can it be accessed online?”

I would have pressed very hard on this without giving way.

Anonymous said...

Wow, 340 ug/m3!!!!

ug = microgram = 1 millionth of a gram = not very much.

Sooo, we have 340 of these things that weigh 1 millionth of a gram per cubic meter.


Under STP (standard temperature and pressure) a liter of air weighs about 1.286 grams.

A cubic meter(M3) of air is 1,000 liters and weighs about 1,286 grams.

1,286 grams X 1,000,000 ug/gram = 1.286 billion ug of air per m3.

That gives us 1 ug of stuff per every 3.782 million ug of air!!!!

If we were talking about inches, that is 1 inch to every 59.69 miles.

Open some windows and you have 1 inch to 338 miles or 1 ug of stuff to 21.4 ug of air.

Politicians are worried about this??????

Gary K.

Anonymous said...

"Open some windows and you have 1 inch to 338 miles or 1 ug of stuff to 21.4 ug of air."

That should read 21.4 million ug of air.

Gary K.

JJ said...

So - what you're saying Gary, is that the amounts of smoke particles under consideration are so small as to be almost illusory?