Safe levels: the riddles of exposure to particulate matter

Enjoy this new report from ASH Scotland's Refresh project, funded by a Big Lottery grant. 'Refresh' is a near-acronym made up of the words 'Reducing Families' Exposure to Second-hand Smoke', and the report guides people working with expectant mothers and fathers to the best way to reduce secondary smoke exposure.

Interestingly the report doesn't mention third-hand smoke, but it does insist that there are 'NO safe levels of exposure to second-hand smoke'. As ever, there is a rider to this: the World Health Organisation has set a 'safe level' of PM2.5 (fine particulate matter, which ASH Scotland claims to be constituted chiefly of smoke). The document says:

• The World Health Organisation (WHO) recommends levels of indoor airborne fine particulate matter (PM2.5) should be below 25 micrograms per cubic metre of air (25 μg/m3) averaged over 24-hours. 

• The average PM2.5 level in a typical smoker’s home is four times higher than the WHO guidance limit.

• A typical car journey where one person smokes exposes non-smokers to levels of PM2.5 that are about three times higher than the guidance limit.

The document is poorly referenced: the first bullet point gives as its reference Bonn: The WHO European Centre for Environment and Health; 2010, but the other two don't give a reference. An intriguing omission, given the figures involved. Recently we were told that the levels of toxins in a car containing a smoker would expose a passenger to levels of toxins 23 times higher than in a smoky bar. This figure was quickly corrected to 11. 


Taken together surely we are being told that passengers are being exposed to 100 micrograms per cubic metre in a car, but for a smoky bar exposure is only 9 micrograms per cubic metre, well below the guidance limit.


All the figures are of course plucked from the air (where are the references?). It is impossible to define the level of fine particulate matter in 'a smoky car', 'a smoky bar' or the home of a 'typical smoker'. Too many variables are involved even to give a sensible average. It is stretching credibility to claim that exposure to smoke in cars is any greater than smoking in a bar, never mind eleven times greater. It is also hard to believe that somebody's home is smokier than bars used to be.

More on PM2.5 measurements here.

Here, find a resounding endorsement of ASH Scotland from the members of the Scottish Parliament.

Pharmaceutical sponsorship in smoking cessation: Toronto conference, November

Back in April, the World Health Organisation warned health professionals working in tobacco control not to become too involved with pharmaceutical companies. But the horse had already escaped. The creation of a global smoking cessation industry was already in its late stages, and continues to develop apace.

Michael Siegel blogs today on the 7th National Conference on Tobacco or Health being held in Toronto in June with Pfizer as a major sponsor. There is a significant conflict of interest (private v. public), since Pfizer manufactures Champix among other smoking cessation medications. Accepting sponsorship from Pfizer will compromise the integrity of the conference.

In March Siegel wrote a piece about ISPTID: the International Society for the Prevention of Tobacco Induced Diseases, in which he remarked that this society had renounced pharmaceutical funding and declared itself free of all industrial ties (before the advice from WHO had been published in the BMJ). He urges other organisations in this field to follow suit: but it will take a wholesale change for many years before I would have any confidence that the slate was clean of pharmaceutical influence. We know, in addition to the pharma-funded events that Siegel lists, that the major UK conference (UK National Smoking Cessation Conference) relies on pharmaceutical sponsorship.

Grants from the Robert Wood Johnson Foundation (a trust part-funded by profits from Johnson & Johnson) can be seen here. The list of grants (using 'tobacco' as a search term) contains some 1,650 entries with over $100,000 awarded for most of them.

It is probable that if all conference organisers wanted to find a willing source of funds for smoking cessation events and they were not permitted to take on pharmaceutical funding, they would find few people willing to come forward, and even fewer with a specific interest in coming forward, year after year in several different locations in any given period.

Netherlands and Scotland plough different furrows

A short Dutch report tells us that the smoking ban is a far more relaxed affair in Dutch bars, with ashtrays in over half of them (note, you can still get a drink in a non-smoking environment in the Netherlands if that's what you prefer).

In Scotland further bans are still being discussed. Sheila Duffy explains in her (comment-free) blog that ASH Scotland supports a public consultation on extending the smoking ban to private cars (smoking is already banned in work vehicles) – whereas the British Medical Association has called for an overall ban on smoking while driving.

It's unusual for ASH Scotland not to bid for the most extreme action going on smoking. Ms Duffy claims that household exposure is a more important problem ('likely to be a greater source of exposure for children'), but is 'not an area for legislation'. Does this mean that she takes issue with Dr Douglas Noble's conclusion (quoted here) that:

In cars, particle concentrations are 27 times higher than in a smoker’s home and 20 times higher than in a pub, in the days when you could smoke in public places.

Even if ASH Scotland has not advocated a total ban in cars, the idea will go before legislators. It's interesting to speculate whether, in responding to the public consultation it seeks, ASH Scotland would oppose a smoking ban in cars, or whether it would simply sit on the fence.

A report and summary of last year's study on smoking in cars by NHS Greater Glasgow (with a headline designed to sensationalise the issue) can be found here (same text here with comments). Also discussed here.

We won't know the legislative programme on smoking in Scotland until after the Scottish Parliament reconvenes in September. But it won't resemble the Dutch one.