The impact of the Tobacco Heating System 2.2 (THS 2.2) on indoor air quality was evaluated in an environmentally controlled room using ventilation conditions recommended for simulating "Office", "Residential" and "Hospitality" environments and was compared with smoking a lit-end cigarette (Marlboro Gold) under identical experimental conditions. The concentrations of eighteen indoor air constituents (respirable suspended particles (RSP) < 2.5 μm in diameter), ultraviolet particulate matter (UVPM), fluorescent particulate matter (FPM), solanesol, 3-ethenylpyridine, nicotine, 1,3-butadiene, acrylonitrile, benzene, isoprene, toluene, acetaldehyde, acrolein, crotonaldehyde, formaldehyde, carbon monoxide, nitrogen oxide, and combined oxides of nitrogen) were measured. In simulations evaluating THS 2.2, the concentrations of most studied analytes did not exceed the background concentrations determined when non-smoking panelists were present in the environmentally controlled room under equivalent conditions. Only acetaldehyde and nicotine concentrations were increased above background concentrations in the "Office" (3.65 and 1.10 μg/m(3)), "Residential" (5.09 and 1.81 μg/m(3)) and "Hospitality" (1.40 and 0.66 μg/m(3)) simulations, respectively. Smoking Marlboro Gold resulted in greater increases in the concentrations of acetaldehyde (58.8, 83.8 and 33.1 μg/m(3)) and nicotine (34.7, 29.1 and 34.6 μg/m(3)) as well as all other measured indoor air constituents in the "Office", "Residential" and "Hospitality" simulations, respectively.

Despite the growing popularity of new alternatives to traditional tobacco products, there is still limited evidence on their indoor effect in particular in residential spaces as specific environments where enforcement of air quality standards is difficult. Hence, the impact of the Tobacco Heating System 2.2 (THS, marketed as IQOS®) on indoor air quality was assessed under controlled experimental conditions using ventilation representative of residential buildings with natural ventilation. Smoking of cigarettes (Marlboro Gold®) at the same ventilation conditions and consumption rates was used as positive control. Before each THS 2.2 or Marlboro Gold session, a background session with the same volunteers as for the product-use session was held. In the high-load simulated residential environment, out of the 24 measured airborne constituents, only the increase of the indoor concentrations of nicotine, acetaldehyde, and glycerin above the background was attributable to the use of THS 2.2. The quantified concentrations of these three airborne compounds were significantly below the harmful levels defined in the air quality guidelines. Smoking Marlboro Gold resulted in much greater increases in the concentrations of all measured indoor air constituents, except for glycerin, and the indoor concentrations of several constituents exceeded the exposure levels set forth by cognizant authorities. Based on these data, it is reasonable to conclude that the use of THS 2.2 in environments where norms for indoor exposure in terms of adequate ventilation are respected does not adversely affect the overall indoor air quality.

SUMMARYPhilip Morris International has developed a heat-not-burn tobacco heating system (THS 2.2) that produces an aerosol without combustion. Adult smokers are anticipated to use the product with differing behaviors, such as puffing volume or puffing frequency, therefore it was important to find an easy way to study how users are exposed to the aerosol constituents. Thus, the intended outcome of this study was to propose and assess a simple approach for the estimation of THS users' exposure to harmful and potentially harmful constituents (HPHCs). THS operates using tobacco sticks (HeatSticks) that include a mouthpiece and a tobacco plug which, when heated, generates an aerosol. The analysis of nicotine retained in the mouthpiece of the HeatSticks during use was identified as a potential approach to estimate users' mouth level exposure (MLE) to HPHCs. Consequently, the following study was conducted with the objectives 1.) to assess the correlation between the quantity of retained nicotine in the mouthpiece (Nicotine MP) of the HeatSticks and the nicotine delivered in the aerosol of machine-smoked products, 2.) to verify the practical range for Nicotine MP based on the analysis of used HeatSticks left by THS users, and 3.) to develop models describing the relationship between Nicotine MP and specific aerosol constituents measured in the aerosol of machine-smoked products. The regular non-mentholated HeatSticks variant was machine-smoked under various smoking regimens to cover the range of anticipated human puffing behaviors. The suitability of this practical range of machine-smoking conditions was verified by collecting used HeatSticks from two different trials conducted with THS users. The determined Nicotine MP distribution indicated that the machinesmoked regimens encompassed the range observed for users. Multiple Linear Regression (MLR) combined with a stepwise approach was used for selecting models describing the relationship between Nicotine MP and specific aerosol constituents. The stepwise approach interactively explores which amongst various tested predictors provides a good fit. The developed models showed good adjusted coefficients of determination (i.e., R 2 adj. $ 0.75) for 28 out of the 43 investigated HPHCs. Previously published studies showed that actual MLE can be estimated from cigarette filter analysis. This study demonstrated that the analysis of nicotine in THS mouthpiece (filter section) corresponded to an estimation of the upper limits of MLE, in line with maximum possible usage conditions. [Beitr. Tabakforsch. Int. 27 (2017) 42-64]