Table 5

Thirdhand smoke pollutants in dust, surfaces and in the air of cars rented as non-smoker, smoker and unknown designations

Car reservation and pickup: type of car requested by confederate
Non-smokerNo preference stated: unknown designationSmoker
LocalNationalLocalNationalLocalNational
Dust nicotine (μg/g)
 25th Percentile4.92.43.44.816.84.4
 Median; geometric mean* 8.1; 10.24.2; 9.216.7; 15.814.4; 13.933.2; 33.714.3; 16.1
 75th Percentile28.623.166.735.552.157.9
 Max46.055.681.6485.3936.5384.7
 % More than threshold (6.18 μg/g)§ 754560679360
Surface nicotine (μg/m2)
 25th Percentile000.100.30.1
 Median; geometric mean 0.2; 0.70.2; 0.50.4; 1.00.2; 0.70.9; 1.91.5; 1.7
 75th Percentile1.20.91.31.02.93.1
 Max17.75.968.842.5506.870.8
 % More than threshold (0.14 μg/m2)§ 525466578872
Air nicotine (ng/m3)
 25th Percentile8.26.87.211.617.74.0
 Median; geometric mean 24.0; 21.417.8; 24.917.7; 17.530.2; 27.250.4; 47.225.0; 25.4
 75th Percentile62.670.145.365.185.689.6
 Max292.6341.5224.3593.5814.5889.3
 % More than threshold (20 ng/m3)§ 574446637166
Air 3-EP (ng/m3)
 25th Percentile2.32.72.23.33.12.3
 Median; geometric mean 9.3; 9.96.7; 8.78.4; 7.812.1; 10.626.9; 22.612.4; 11.5
 75th Percentile44.922.518.426.686.733.5
 Max270.8202.3222.5179.9292.4564.6
  • * Pairwise comparison for dust nicotine levels: p<0.05 (Tukey HSD) non-smoker versus smoker.

  • Pairwise comparisons for air nicotine and air 3-EP: are not statistically significant, p>0.05 (Tukey HSD).

  • Pairwise comparisons for surface nicotine: p<0.05 (Tukey HSD): non-smoker versus unknown; unknown versus smoker car.

  • § Thresholds based on used cars for sale by non-smokers with a car smoking ban.7