Testing the mHealth App Intervention for Nondaily Smokers "SiS4"

The goal of this project is to test if a new behavioral treatment for people who smoke nondaily and wish to quit works. The new treatment is a smartphone app that engages users in positive psychology exercises and gives them tested tools for quitting smoking. The positive psychology exercises help users maintain their positive emotions while they quit smoking. This app has been developed with and for people who smoke nondaily through several steps of development. The main questions it aims to answer are: * Does the smoking cessation app (SiS4) help people who smoke nondaily quit smoking? * How do people's attitudes towards smoking, their smoking urges, and their mental well-being shift when using the SiS4 app? Researchers will compare the new app to an existing app that was developed for people who smoke daily to see if the new app works better to help people who smoke nondaily quit smoking. Participants will: 1. Use a smartphone app every day for 7 weeks 2. Complete online surveys about their smoking, attitudes about smoking, withdrawal symptoms and smoking urges, app use, and mental well-being at enrollment as well as 2 weeks, 6 weeks, 3 months, 6 months and 12 months after the initially chosen quit date. If the SiS4 app works well, it would be the first evidence-based quit-smoking treatment for people who smoke nondaily.