Impacts of exhaled aerosol from the usage of the tobacco heating system to indoor air quality: A chamber study.

Aerosol particle, carbonyl, and nicotine concentrations were analysed as pollutants affecting indoor air quality during the usage of electrically-heated tobacco product - the Tobacco Heating System (THS). Quantitative experimental variables included THS use intensity as number of parallel users (1, 3, or 5), distance to the bystander (0.5, 1, or 2 m), as well as environmental conditions in a chamber: ventilation intensity as air changes per hour (0.2, 0.5, or 1 h-1), and relative humidity (RH, 30, 50 or 70%). The real-time particle number (PNC), CO and CO2 concentration, as well as off-line acetaldehyde, formaldehyde, nicotine, and 3-ethenylpyridine concentration was measured during and after the active usage. Use of THS resulted in a statistically significant increase of several analytes including nicotine, acetaldehyde, PM2.5, and PNC as compared to the background. The obtained levels were significantly lower (approximately 16, 8, 8 and 28 times for nicotine, acetaldehyde, PNC and PM2.5, respectively) compared to the levels resulting from conventional cigarette (CC) smoking under identical conditions. The maximum 30 min concentration of PNC (4.8 × 105 #/cm3), as well as maximum concentration of PNC (9.3 × 106 #/cm3) suggest that the intensive use of THS in a confined space with limited ventilation might cause substantially elevated aerosol concentrations, although these particles appeared as highly volatile ones and evaporated within seconds. Generally, the usage intensity (number of simultaneous users) prevailed as the most important factor positively affecting pollutant variations; another important factor was the distance to bystander.