Thirdhand smoke: Chemical dynamics, cytotoxicity, and genotoxicity in outdoor and indoor environments

Abstract

We tested the toxicity of thirdhand smoke (THS) using two controlled laboratory exposure scenarios and low levels of THS. One exposure modeled THS in a car parked outdoors, while the second modeled THS in a room without sunlight. The fabrics were exposed to cigarette smoke and then extracted in culture medium. Concentrations of nicotine, nicotine related alkaloids, and tobacco specific nitrosamines (TSNAs) were determined in fresh and aged extracts. The concentration of TSNAs increased with aging in the indoor experiment. THS extracts were used for cytotoxicity testing using mouse neural stem cells (mNSC), human dermal fibroblasts (hDF) and human palatal mesenchyme cells (hPM). Extracts from the car experiment inhibited mNSC proliferation in a live cell imaging assay and induced single strand DNA breaks in mNSC and hDF. In the indoor experiment, THS extracts made with medium containing serum proteins were significantly more toxic than extracts made with basal medium, and mNSC and hPM were more sensitive than hDF. These data indicate that: (1) aging of THS chemical differs on different fabrics and differs with and without sunlight; (2) very few cigarettes are sufficient to produce a toxic THS residue; and (3) protein enhances the efficiency of extraction of cytotoxic chemicals.

Liquid Chromatography Electrochemical Determination of Nicotine in Third‐Hand Smoke

“…Recent research [6][7][8] has demonstrated that not only are individuals at risk from smoking itself or second hand smoke produced, but they are also exposed to what is referred to as third hand smoke (THS). THS is formed from tobacco smoke or vapour and remains deposited after the smoking has ceased.…”

“…Studies have found that nicotine and other compounds can be found in house dust, cars and hotel rooms and on surfaces [6]. The deposited nicotine can react with pollutants, such as nitrous acid and ozone to form toxic and potentially mutagenic and cytotoxic compounds known as tobacco-specific nitrosamines (TSNAs) [7,8] which can be reemitted back into the environment by degassing or through movements of dust [6].…”

Thirdhand smoke: when the danger is more than you can see or smell

“…Murine neural stem cells (mNSC) and human dermal fibroblasts (hDF) were exposed to a culture medium prepared with fabric material present inside automobiles from which THS was collected and evaluated with the comet assay. Cells treated with this material showed a higher percentage with migration of chromosomal DNA and longer tails 62 . Chronic exposure to THS resulted in oxidative DNA damage in genes involved in nucleotide metabolism and repair mechanism in human bronchial epithelial cells (BEAS-2B) 72 .…”

“…De novo formation of these nitrosamines was also proven in a longitudinal experiment by the increase in concentration during months in which there was no exposure to cigarette smoke 62 .…”

“…THS cytotoxicity was verified by altered mitochondrial function in mNSC, but the potential for damage decreased as the sample aged 62,75,76 . There was even a decrease in the total number of cells, caused by inhibition of cell proliferation.…”