Fig. 2
Surface pressure vs. surface area isotherms of Infasurf® before and after exposure to various amounts of e-cigarette vapor and cigarette smoke. a Control (exposed to clean air), (b) exposed to unflavored e-cigarettes, (c) exposed to e-cigarettes with mint flavoring, (d) exposed to e-cigarettes with berry flavoring, (e) exposed to smoke from 1R6F conventional cigarettes, and (f) surface pressure vs. surface area isotherms of 900 mL of vapor or smoke bubbled in the subphase with no surfactant present (note that except for 1R6F cigarette all lines are close to zero), significant increase in surface pressure compared to control (using a p-value of 0.05) is shown by *