This is a research study that will test a new remote monitoring technology to assess smoking in the natural environment among adolescents and young adults ages 15-25. After assessment and inclusion in the study, participants will be asked to report on their smoking by answering questions on a mobile phone for 35 days. Participants will also be asked to make a brief quit attempt lasting for approximately 48 hours. There is no cost to participate and compensation is available to those who qualify.

The purpose of this study is to assess the effects of N-Acetylcysteine (NAC), an over-the-counter antioxidant, to assist adult cigarette smokers with quitting and preventing relapse to smoking. This medication may help people quit smoking by reducing withdrawal symptoms, craving, and preventing relapse, but we do not know if NAC helps smokers early in their quit attempt or after they have already quit.