The interaction of ozone with nicotine sorbed to Teflon or cotton surfaces was investigated in an environmental chamber by monitoring nicotine desorption over a week following equilibration in dry or humid air (65-70 % RH). The Teflon and cotton surfaces had N2-BET surface areas of 0.19 and 1.17 m2 g-1, and water mass uptakes (at 70 % RH) of 0 and 7.1 % respectively. In dry air, gas phase nicotine concentrations decreased with respect to baseline (no O3) levels by 2 orders of magnitude for Teflon after 50 h at 20-45 ppb O3, and by a factor of 10 for cotton after 100 h with 13-15 ppb O3. The ratios of pseudo first-order rate constants for surface reaction (r) to long-term desorption (k) were r/k = 3.5 and 2.0 for Teflon and cotton surfaces, respectively. Formaldehyde, N-methylformamide, nicotinaldehyde and cotinine were identified as oxidation products, indicating that the pyrrolidinic N was the site of electrophilic attack by O3. The presence of water vapor had no effect on the nicotine-O3 reaction on Teflon surfaces. By contrast, nicotine desorption profiles from cotton in humid air were identical in the presence or absence of ozone. The latter phenomenon is ascribed to complete inhibition of ozone-nicotine surface reactions by co-sorbed water through decomposition of ozone in the aqueous surface film and/or interactions of nicotine with water that reduced its reactivity towards ozone. Oxidative losses of sorbed nicotine and reduction in its re-emission could attenuate possible biases in use of nicotine as a tracer for environmental tobacco smoke.