Reference Standards 2010

The smoking load calculator has used readily derived conversion figures which have been taught at the National Respiratory Training Centre at Warwick, England over the last seventeen years. This is not an exact science and approximations have been made, for example a cigarillo is 2 cigarettes and a cigar is 4 cigarettes. Loose tobacco estimates that 25 grams (1 oz) has been approximated to be the equivalent of 50 cigarettes. One pipe is equivalent to 2½ cigarettes. The original work from which these figures were obtained could not be found by the present authors. Nevertheless as large numbers of practice nurses had been trained using these apparently unreferenced figures, it was decided by the authors to continue to use this data in the world’s first pack year calculator.

Other references that have been used are listed below:

1. Effects of cannabis on pulmonary structure, function and symptoms. Sarah Aldington, et al, Thorax 2007;62(12):1058-63. doi:10.1136/thx.2006.077081
   
   This study suggested that the smoking effects of one spliff could be compared to between 2½ and 5 cigarettes. In the ‘pack year’ calculator we gave a figure of 4, i.e. the same as a cigar.
2. TobReg Advisory Note: Waterpipe tobacco smoking: Health effects, research needs and recommended actions by regulators WHO study group on tobacco product regulation (Tob Reg) 2005
   
   From this document an 80 minute session is equivalent to 100 cigarettes, i.e. 20 minutes is equivalent to 25 cigarettes.
3. Wood D M, et al ‘Pack year’ Smoking Histories: What about patients who use loose tobacco?
   Tobacco Control 2005;14(2):141-142
4. dva.gov.au/media 2003 Australian gulf war veterans health study
5. Bidis have been added to the calculator in 2024 for the first time. One Bidi is equivalent to half a cigarette.
   Concept of Bidi years. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9390292

References 3 and 4 were used to check that our approximated unreferenced figures were close to others working in this area.