Indoor concentrations of nicotine in low-income, multi-unit housing: associations with smoking behaviours and housing characteristics

Objective: An analysis of airborne nicotine measurements collected in 49 low-income, multi-unit residences across the Greater Boston Area. Methods: Nicotine concentrations were determined using passive monitors placed in homes over a one-week sampling period and air exchange rates (AER) were sampled using the perfluorocarbon tracer technique. Residents were surveyed through a questionnaire about smoking behaviour and a visual inspection was conducted to collect information on housing characteristics contributing to secondhand smoke (SHS) exposure. Using a mass balance model to account for the air exchange rate, volume of the home and sorption and re-emission of nicotine on indoor surfaces, the effective smoking rate (SReff) was determined for each residence. Results: Nicotine levels ranged from the limit of detection to 26.92 mu g/m(3), with a mean of 2.20 mu g/m(3) and median of 0.13 mu g/m(3). Nicotine measurements were significantly associated with the number of smokers in the household and the number of cigarettes smoked in the home. The results of this study suggest that questionnaire reports can provide a valid estimate of residential exposure to tobacco smoke. In addition, this study found evidence that tobacco smoke contamination in low-income housing developments is not limited to homes with smokers (either residing in the home or visiting). The frequent report of tobacco smoke odour coming from other apartments or hallways resulted in increased levels of nicotine concentrations and SReff in non-smoking homes, suggestive of SHS infiltration from neighbouring units. Conclusion: These findings have important implications for smoking regulations in multi-unit homes and highlight the need to reduce involuntary exposure to tobacco smoke among low-income housing residents.