Effect of ventilation on passive smoking risk in a model workplace

An estimate of the variation of non smokers' lung cancer risk from passive or involuntary smoking is given as a function of ventilation rate in a typical office, at an occupancy of 7 persons/100m2 as specified under ASHRAE standard 62-1981. Assuming one third of the office workers are smokers who smoke at the average rate of two cigarettes per hour, the nonsmoking office workers exposed to environmental tobacco smoke for a 40 year period under the ventilation rate of 10 LPS/per occupant, recommended by the standard would be subject to an estimated lifetime unvoluntary risk of about 250 per 100,000. Decreasing the ventilation rate to the minimum permitted under ASHRAE 62-1981 (2.5 LPS/per occupant), produces a four fold increase in risk.