Exhaled aerosols were collected following the use of two leading US commercial electronic cigarettes and a conventional cigarette by human subjects and analyzed for phenolics, carbonyls, water, glycerin and nicotine using a vacuum-assisted filter pad capture system. ISO 17025 accredited methods for conventional cigarette smoke analyses were adapted and verified for use with exhaled cigarette smoke and exhaled e-cigarette aerosols. Exhaled breath blanks were determined for each subject prior to each product use session. Distribution and mass balance of exhaled e-cigarette aerosol showed the composition was greater than 99.9% water and glycerin, and a small amount (<0.06%) of nicotine. Total phenolic content in exhaled e-cigarette aerosol was not distinguishable from exhaled breath blanks, while total phenolics in exhaled cigarette smoke were significantly greater than in exhaled e-cigarette aerosol and exhaled breaths averaging 75 µg/session (range 45 to 158 µg/session). The total carbonyls in exhaled e-cigarette aerosol were also not distinguishable from exhaled breaths or room air blanks. Total carbonyls in exhaled cigarette smoke were significantly greater than in exhaled e-cigarette aerosols, exhaled breath and room air blanks, averaging 242 µg/session (range 136 to 352 µg/session). These results suggest that exhaled e-cigarette aerosol does not increase bystander exposure for phenolics and carbonyls above the levels observed in exhaled breaths of air.