Formation of carcinogens indoors by surface-mediated reactions of nicotine with nitrous acid, leading to potential thirdhand smoke hazards.
This study shows that residual nicotine from tobacco smoke sorbed to indoor surfaces reacts with ambient nitrous acid (HONO) to form carcinogenic tobacco-specific nitrosamines (TSNAs). Substantial levels of TSNAs were measured on surfaces inside a smoker's vehicle. Laboratory experiments using cellulose as a model indoor material yielded a > 10-fold increase of surface-bound TSNAs when sorbed secondhand smoke was exposed to 60 ppbv HONO for 3 hours. In both cases we identified 1-(N-methyl-N-nitrosamino)-1-(3-pyridinyl)-4-butanal, a TSNA absent in freshly emitted tobacco smoke, as the major product. The potent carcinogens 4-(methylnitrosamino)-1-(3-pyridinyl)-1-butanone and N-nitroso nornicotine were also detected. Time-course measurements revealed fast TSNA formation, with up to 0.4% conversion of nicotine. Given the rapid sorption and persistence of high levels of nicotine on indoor surfaces-including clothing and human skin-this recently identified process represents an unappreciated health hazard through dermal exposure, dust inhalation, and ingestion. These findings raise concerns about exposures to the tobacco smoke residue that has been recently dubbed "thirdhand smoke." Our work highlights the importance of reactions at indoor interfaces, particularly those involving amines and NO(x)/HONO cycling, with potential health impacts.
Indoor Environment Department, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 70-108B, Berkeley, CA 94720, USA.
Mohamad
M
Sleiman
Lara A
LA
Gundel
James F
JF
Pankow
Peyton
P
Jacob
Brett C
BC
Singer
Hugo
H
Destaillats
D000327:Adsorption; D002273:Carcinogens / Q000737:chemistry*; D002482:Cellulose / Q000737:chemistry; D002621:Chemistry / Q000379:methods; D002849:Chromatography, Gas / Q000379:methods; D005740:Gases; D006801:Humans; D007700:Kinetics; D009538:Nicotine / Q000737:chemistry*; D009589:Nitrogen Oxides / Q000737:chemistry; D009608:Nitrous Acid / Q000737:chemistry*; D013499:Surface Properties; D053719:Tandem Mass Spectrometry / Q000379:methods; D014028:Tobacco Smoke Pollution
D002273:Carcinogens; D005740:Gases; D009589:Nitrogen Oxides; D014028:Tobacco Smoke Pollution; D009538:Nicotine; D002482:Cellulose; D009608:Nitrous Acid