Assessing Material Surface Staining by Heated Tobacco Product and e-Vapor Aerosols versus Cigarette Smoke

Environmental tobacco smoke (ETS) comprising cigarette sidestream and exhaled mainstream smoke discolors indoor surfaces, particularly light-colored materials. The use of heated tobacco products (HTPs) and e-vapor products (EVPs) is less likely to stain indoor surfaces due to the lack of smoke and the drastic reduction of aerosol emissions resulting from the negligible sidestream, and the less complex composition of the mainstream emission. Few studies have compared indoor material staining by ETS with HTP and EVP environmental aerosols under controlled conditions. A test chamber was developed, allowing simulation of a standard residential setting. Four typical indoor materials (cellulose wallpaper, cotton fabric, polypropylene placemat, polypropylene tablecloth) were exposed to mainstream and sidestream cigarette smoke (200 puffs, one pack), HTP aerosol (240 puffs, one pack), or EVP aerosol (240 puffs, ca. one cartridge). Readings were carried out immediately after exposure and after a 28-day aging period using the Commission Internationale de l’Eclairage L*a*b* color space. Color changes between non-exposed and exposed samples were calculated. The noticeability of the color changes by a standard observer and their acceptability were determined. Cigarette smoke caused the freshly exposed materials to darken and yellow, while HTP and EVP aerosols induced minimal or no color change. Aging only affected the cotton fabric, which yellowed, particularly after exposure to cigarette smoke. The natural composition of cotton and thus its wettability likely facilitated diffusion of the responsible staining molecules. Overall, color changes following HTP and EVP aerosol exposure were lower (by at least 90%) than those caused by cigarette smoke.