Effect of Ozone on Nicotine Desorption from Model Surfaces: Evidence for Heterogeneous Chemistry

详细信息    查看全文

• 作者：Hugo Destaillats ; Brett C. Singer ; Sharon K. Lee ; and Lara A. Gundel
• 刊名：Environmental Science & Technology
• 出版年：2006
• 出版时间：March 15, 2006
• 年：2006
• 卷：40
• 期：6
• 页码：1799 - 1805
• 全文大小：134K
• 年卷期：v.40,no.6(March 15, 2006)
• ISSN：1520-5851

文摘

Assessment of secondhand tobacco smoke exposureusing nicotine as a tracer or biomarker is affected bysorption of the alkaloid to indoor surfaces and by its long-term re-emission into the gas phase. However, surfacechemical interactions of nicotine have not been sufficientlycharacterized. Here, the reaction of ozone with nicotinesorbed to Teflon and cotton surfaces was investigated inan environmental chamber by monitoring nicotinedesorption over a week following equilibration in dry orhumid air (~0% or 65-70% RH, respectively). The Teflonand cotton surfaces had N₂-BET surface areas of 0.19 and1.17 m² g^-1, and water mass uptakes (at 70% RH) of 0and 7.1% respectively. Compared with dry air baseline levelsin the absence of O₃, gas-phase nicotine concentrationsdecreased by 2 orders of magnitude for Teflon after 50 h at20-45 ppb O₃, and by a factor of 10 for cotton after 100h with 13-15 ppb O₃. The ratios of pseudo first-order rateconstants for surface reaction (r) to long-term desorption(k) were r/k = 3.5 and 2.0 for Teflon and cotton surfaces,respectively. These results show that surface oxidationwas competitive with desorption. Hence, oxidative lossescould significantly reduce long-term re-emissions ofnicotine from indoor surfaces. Formaldehyde, N-methylformamide, nicotinaldehyde, and cotinine were identified asoxidation products, indicating that the pyrrolidinic N was thesite of electrophilic attack by O₃. The presence of watervapor had no effect on the nicotine-O₃ reaction on Teflonsurfaces. By contrast, nicotine desorption from cotton inhumid air was unaffected by the presence of ozone. Theseobservations are consistent with complete inhibition ofozone-nicotine surface reactions in an aqueous surfacefilm present in cotton but not in Teflon surfaces.