Comparison between particulate matter and ultrafine particle emission by electronic and normal cigarettes in real-life conditions.

Aims: Electronic cigarettes may be safer than conventional cigarettes as they generate less indoor pollution in terms of particulate matter (PM); however, recent findings in experimental conditions demonstrated that secondhand exposure to PM may be expected from e-cigarette smoking. The aim of the present study was to investigate the emission of PM generated by e-cigarettes and normal cigarettes under real-life conditions.

Methods: Real-time measurement and comparison of PM and ultrafine particles (UFP) generated by electronic cigarettes with and without nicotine and by normal cigarettes in a 50 m3 office of an Italian comprehensive cancer center was performed. PM mass as PM1, PM2.5, PM7, PM10, total suspended particles (TSP) in μg/m³ and UFP in number of particles per cubic centimeter from 10 to 1,000 nanometers were measured. Outdoor concentrations were measured contemporaneously to compensate for urban background changes.

Results: Regardless of their nicotine content, e-cigarettes generated lower PM levels than conventional cigarettes. Notably, nicotine-enriched e-cigarettes produced lower PM levels than their nicotine-free counterparts.

Conclusion: E-cigarettes appear to generate less indoor pollution than normal cigarettes and may therefore be safer. Further studies are required to investigate the long-term health-related effects of secondhand e-cigarette exposure.