Journal Letter 1)
In a previous study1 of ‘secondhand’2) cigarette smoke, we showed that 75% of the particles added to indoor air were of ultrafine sizes and had a half-life in air of 18 minutes at 25°C. These particles after their deposition on household surfaces could be later put back in suspension and constitute a toxic ‘thirdhand’3) smoke2 which has not, as yet, been documented through quantitative data. Consequently, we undertook direct measurements of the concentration and sizes of smoke particles after their deposition and resuspension in a closed room.
A smoking device burned 10 cigarettes in 30 minutes in a non-ventilated furnished room that was then kept closed. On the next day, for particle resuspension, we mobilised the dust on furniture, clothes and surfaces by wiping and shaking and created even more turbulence with a ventilator.
An impactor (ELPI) measured the particle sizes (between 0.28 μm and 10 μm) and concentration in the air, 60 cm above the floor:
Median diameter, concentration in number and mass of particles were respectively:
This showed that after cigarette smoking:
These quantitative data support the hypothesis of a resuspension from the cigarette smoke surface contamination. However, this airborne contamination through resuspension remains much lower (100 times) than that of secondhand smoke. The rest of the aerosol mass initially produced by cigarettes could be firmly attached either to surfaces, leading to ingestion hazards and dermal transfer or to household dust and be inhaled with it.3 4
1 Becquemin MH, Bertholon JF, Attoui M, et al. Rétention dans les voies aériennes des particules nanométriques de l'aérosol de la fumée de cigarette au cours du tabagisme passif. Rev Mal Respir 2010. doi:10.1016/j.rmr.2010.03.01.
2 Winickoff JP, Friebely J, Tanski E, et al. Beliefs about health effects of “thirdhand” smoke and home smoking bans. Pediatrics 2009;123:e74–9.
3 Matt GE, Quintana PJE, Hovell MF, et al. Households contaminated by environmental tobacco smoke: sources of infant exposures. Tob Control 2004;13:29–37.
4 Matt GE, Quintana PJE, Hovell, et al. Residual tobacco smoke pollution in used cars for sale: air, dust, and surfaces. Nicotine Tob Res 2008;10:1467–75.