In previous studies of the smoke from regular cigarettes and water pipes, we measured
aerosol particle sizes in three streams; S1, inhaled by the smoker, S2, released by
the device itself and S3, exhaled by the smoker. We used an electrostatic low-pressure
impactor (ELPI), giving particle size distributions in real time and calculated median
diameters, D50, and dispersion (σg). This allowed us to predict airway deposition.
In addition, the aerosol particle half-life in the air was used as a measure of the
risk to others from passive smoking. With the same equipment, we measured the particle
sizes and persistence in air of the liquid aerosol generated by e-cigarettes (Cigarettec®)
containing water, propylene glycol and flavorings with or without nicotine. Aerosol
generation was triggered by a syringe or by the inspiration of volunteer smokers.
The D50 data obtained in S1, were 0.65 μm with nicotine and 0.60 μm without nicotine.
Deposition in the airways could then be calculated: 26% of the total would deposit,
of which 14% would reach the alveoli. These data are close to those found with regular
cigarettes. For S3, D50 data were 0.34 μm and 0.29 μm with or without nicotine. The
half-life in air of the S3 stream was 11 seconds due to a rapid evaporation. The-e-cigarette
aerosol, as measured here, is made of particles bigger than those of cigarette and
water pipe aerosols. Their deposition in the lung depends on their fate in the airways,
which is unknown. Contrary to tobacco smoke, which has a half-life in air of 19 to
20 minutes, the risk of passive "smoking" exposure from e-cigarettes is modest.
Copyright © 2013 SPLF. Published by Elsevier Masson SAS. All rights reserved.