Tobacco smoke pollution of rental cars: Air concentrations of nicotine and 3-EP

Exposure to tobacco smoke pollution (TSP) can occur in the presence of active smoking and long after smoking has taken place, through exposure to residual contamination of air, dust and surfaces. Here we investigated whether residual TSP could be found in cars offered for rent through national and local car rental agencies. Cars (n=250) were rented in San Diego CA, from 2006 – 2008. Nicotine and 3-ethenylpyridine (3-EP) were measured in air using active air sampling, and nicotine measured on surfaces. Samples were analyzed by LC-tandem mass spectrometry using deuterated internal standards. Air concentrations of nicotine were slightly higher in cars designated as ‘smoking' cars (median 0.040 ug/m3 nicotine, max 0.914 ug/m3) than in cars designated as ‘non-smoking' cars (median 0.018 ug/m3 nicotine, max 0.344 ug/m3) and cars of unknown designation (median 0.023 ug/m3 nicotine, max 0.618 ug/m3). The level of 3-EP was about half (median 43.5%) of the level of nicotine in the same air sample. Nicotine and 3-EP were highly correlated (rho = 0.878, p<0.001), indicating that nicotine is a marker for other components of residual TSP contamination of spaces, not merely a uniquely persistent compound. Nicotine levels in air were correlated with wipe sample concentrations of nicotine taken in the same car (rho = 0.240, p=0.006) as was 3-EP (rho = 0.327, p<0.001) These findings suggest that detectable levels of TSP markers can be measured in many rental cars, even though these cars have been cleaned prior to rental.