Selective Uptake of Third-Hand Tobacco Smoke Components to Inorganic and Organic Aerosol Particles.

Third-hand smoke (THS) is an emerging route of exposure to tobacco smoke in the indoor environment. Few studies have investigated the chemical behavior of THS, although initial findings suggest that semivolatile components of THS can partition to indoor aerosol. By exposing single-component particles to THS in an environmental chamber, this study demonstrates a pronounced dependence of THS uptake on aerosol composition. First, it was found that primarily reduced nitrogen compounds (that produced C xH yN z+ ion signal) in THS partitioned strongly to acidic ammoniated sulfate particles, whereas overall THS uptake to more pH-neutral sodium sulfate particles was minimal. Second, THS uptake to pure hydrocarbon particles (squalane) was even greater than to ammoniated sulfate particles with the uptake arising from mainly C xH y compounds. The greater uptake of THS to squalane was mostly driven by the dominant fraction of C xH y compounds in the side stream cigarette smoke aerosol, the composition of which is likely to be broadly similar to THS in these experiments. Third, oxygenated organic particles (sucrose) and solid ammonium sulfate particles showed minimal uptake. These results indicate that particulate THS inhalation exposure will be strongly dependent on the chemical nature of the particles present in the indoor environment.