Simon Chapman has been part of the debate on Stephen Williams MP’s blog. He is Australian and have used Australian statistics for my illustration.
Whether second hand smoke (SHS) causes lung cancer (LC) they need to pay particular attention to role of benzo(a)pyrene (BAP) in p53 mutations and whether the rare cases in non smokers is the result of exposure to second hand smoke or wood/coal smoke, car exhausts, industrial pollution or even BBQs.
Assumptions: Population of Australia 2007 21,200,000
Lung cancer deaths in 2007 in Aus 7,626
LC rate per 100,000 = 35.97 approx = 36
90% of LC deaths are smokers, hence LC rate non smokers = 3.6
If you look at the IARC/WHO database Pfeifer and Hainault 10% of non smokers have the guanine to thymine, p53 mutation. This would give SHS LC rate of 0.36 per 100,000 per year, about 1 person per 300,000 people. About 71 people a year.
HOWEVER, BUT, BUT BUT.
The guanine to thymine transversion is also seen in coal miners from argon exposure who are non smokers. The IARC in their zeal to prove that BAP is the cause of LC have overlooked that BAP is also produced in far higher quantities in wood/coal smoke, car exhausts, industrial pollution or even BBQs. My provenance for this is er, Professor Simon Chapman.
In your letter to tobacco control you cites these papers:
“Ott and Seigmann and Wallace and Ott provide data on fine and ultra-fine particle emissions from different sources: “Controlled experiments with 10 cigarettes averaged 0.15 ng mm-2 … ambient wood smoke averaged 0.29 ng mm-2 or about twice those of cigarettes and cigars … In-vehicle exposures measured on 43 and 50 min drives on a California arterial highway gave PC/DC ratios of 0.42 and 0.58 ng mm-2 … Interstate highways had PC/DC ratios of approximately 0.5 ng mm-2 with ratios above 1 ng mm-2 when driving behind diesel trucks. These PC/DC ratios were higher than the ”signature” value of the cigarette (0.11-0.19 ngmm-2)measured in a large Indian gaming casino with smoking.” 
When it refers to “ultra-fine partiles” I assume you are referring to PM2.5 of which BAP is one. By your own omission you imply that non smokers ingest far more BAP from wood/coal smoke, car exhausts, industrial pollution, candles and BBQs.
It is quite possible that no one in Australia or the world has ever contracted LC from SHS and the very most it is is 71 per year out of a population of 22 million. This would be the equivalent of 210 in the UK, 3,000 people die on the roads every year in the UK, so crossing the road or driving your car is 15 times more dangerous than SHS?
Sorry it is late here and I hope my maths and decimal places are in the right place. My PHD I hope will let us at last have a honest debate.
All I want to do is have a cigarette in peace in a bar.