Secondhand smoke exposure within semi-open air cafes and tobacco specific 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) concentrations among nonsmoking employees

Objectives: Secondhand smoke (SHS) is a defined occupational hazard. The association though between SHS exposure in semi-open air venues and tobacco specific carcinogen uptake is an area of debate. Material and Methods: A cross sectional survey of 49 semi-open air cafes in Athens, Greece was performed during the summer of 2008, prior to the adoption of the national smoke free legislation. All venues had at least 1 entire wall open to allow for free air exchange. Indoor concentrations of particulate matter smaller than 2.5 microns ($\text{PM}_\text{2.5}$) attributable to SHS were assessed during a work shift, while 1 non-smoking employee responsible for indoor and outdoor table service from each venue provided a post work shift urine sample for analysis of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL). Results: Post work shift NNAL concentrations were correlated with work shift $\text{PM}_\text{2.5}$ concentrations attributable to SHS (r = 0.376, p = 0.0076). Urinary NNAL concentrations among employees increased by 9.5%, per 10 μg/m³ increase in $\text{PM}_\text{2.5}$ concentrations attributable to SHS after controlling for the time of day and day of week. Conclusions: These results indicate that the commonly proposed practice of maintaining open sliding walls as a means of free air exchange does not lead to the elimination of employee exposure to tobacco specific carcinogens attributable to workplace SHS.