RecruitingBehavioural interventionCigarette Filter StudyThe overall purpose of this study is to determine the effects of using charcoal-filtered cigarettes on product perceptions, smoking behaviors, and biomarkers of exposure to tobacco-related toxicants. The main questions it aims to answer are: Do perceptions of cigarettes differ by their filter? Do people smoke charcoal-filtered cigarettes differently than cigarettes with conventional filters, and does this change their exposure to cigarette harms? Study participants will complete a 5-week laboratory-based, open-label, parallel-design randomized trial. After a baseline period of smoking their preferred brand, participants will smoke charcoal-filtered or non-charcoal-filtered cigarettes for 4 weeks while completing weekly sessions to assess primary outcomes. During weekly sessions, they will smoke two cigarettes in our laboratory, provide urine and carbon monoxide samples, and complete questionnaires.