This study is an open-label, randomized, 9-week, two-sequence, two-treatment, cross-over clinical trial of 40 adult filtered cigarette smokers who switch to unfiltered cigarettes There will be a 1-week baseline period, 2 weeks of smoking filtered or unfiltered cigarettes (determined at time of randomization), and a 3-week washout period, followed by post-washout baseline week, and a crossover to 2 weeks of smoking the opposite condition.

This innovative research project will assess the acceptability among committed smokers of switching to unfiltered cigarettes from filtered cigarettes and compare the measurement of exposure to nicotine and carcinogens after such a switch from filtered to unfiltered cigarettes. Such research will inform regulatory policy regarding the possibility of banning filters from the U.S. cigarette market. This high-impact pilot project is a randomized, cross-over clinical trial among smokers to measure changes in their puffing behavior, carcinogen exposures, nicotine exposure, and attitudes toward smoking unfiltered cigarettes if they were to no longer able to buy filtered cigarettes. The overall objective for this pilot trial is to collect preliminary data to inform design of a larger clinical trial in assessing changes in attitudes toward smoking unfiltered cigarettes; smoking topography; and urinary cotinine, urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), and volatile organic compound (VOC) excretion resulting from switching from filtered to unfiltered cigarettes among a sample of committed smokers.

Aim 1. Determine smokers' satisfaction, and attitudes towards smoking cigarettes if they were to switch from smoking filtered to unfiltered cigarettes. The investigators hypothesize that smokers who smoke unfiltered cigarettes will have less satisfaction with their smoking compared with smoking filtered cigarettes.

Aim 2. Measure changes in smoking topography and cigarettes smoked per day among smokers who change to unfiltered cigarettes for two weeks compared with these measures while smoking filtered cigarettes. The investigators hypothesize that smokers who smoke unfiltered cigarettes for two weeks will change their topography such that they will inhale less deeply and frequently and will smoke fewer cigarettes per day.

Aim 3. Measure changes in urinary cotinine, NNAL, and VOC excretion among smokers who smoke unfiltered cigarettes for two weeks compared to smoking filtered cigarettes.

The investigators hypothesize that smokers who smoke unfiltered cigarettes for two weeks will have lower urinary cotinine, NNAL, and VOC excretion compared with filtered cigarettes.

The results from this trial can inform a larger clinical trial that can be submitted to the National Institutes of Health/Food and Drug Administration to develop evidence on the potentially positive impact of removing plastic filters from commercial cigarettes. It will allow us to develop sound scientific methods to assess the topography of smoking and excretion of cotinine, tobacco-specific nitrosamines, and VOCs by smokers who smoke cigarettes with and without filters. This new knowledge may lead the Food and Drug Administration or specific states to consider banning the sale of filtered cigarettes because filters make it easier for young people to start smoking, unjustifiably discourage smokers from quitting, and contaminate the environment with non-biodegradable, toxic waste.

Inclusion Criteria:

• Are non-institutionalized, and
• Able to provide informed consent, and
• Are ages 21 to 65, and
• Smoke at least 25 days per month, and
• Smoke at least 5 cigarettes per day on the days they smoke, and
• Have been smoking cigarettes for at least 1 year, and
• Have smoked exclusively Camel or Pall Mall cigarettes over the past two weeks, or are willing to do so for the two weeks prior to, and for seven weeks during, the study, and
• Are fluent in English, and
• Have regular access to a telephone, and
• Have smoked only filtered cigarettes for the past year, and
• Have access to transportation to California State University, San Marcos (CSUSM), and
• Report primary (≥50% of the time) smoking of cigarettes, allowing for secondary use of other tobacco products, and
• Agree to the terms of the trial

Exclusion Criteria:

• Do not meet one or more of the above inclusion criteria, or
• Self-report uncontrolled diabetes (i.e., diagnosed with diabetes, and it is not being managed by a physician), or
• Present to the enrollment visit with a systolic blood pressure greater than 160 mm Hg or a diastolic blood pressure greater than 105 mm Hg, or
• Self-report involvement in another clinical trial, or
• Self-report hospitalization for psychiatric issues or had a heart-related event (e.g. heart attack) at enrollment or within the past 30 days, or
• Self-report attempts to quit or cut down on smoking in past 30 days, or
• Self-report use of pharmacotherapy to aid smoking cessation within the past 30 days, or
• Are breastfeeding, pregnant, or may become pregnant during the next six months, or
• Are planning to move out of San Diego in the next 9 weeks, or
• Do not meet expected expired carbon monoxide (CO) measurements of smokers (Expired CO measurements>10 parts per million (ppm) will confirm status as a current smoker of at >5 cigarettes/day on the initial visit), or
• Are deemed mentally unstable (i.e., psychotic, under influence of drugs or alcohol, or unable to comprehend the call or meeting) or physically unfit (i.e, physically unwell) to participate in the study based on the researcher's determination at the enrollment visit

Individual participant data (IPD), including a data dictionary, will be shared with the study's Data Safety and Monitoring Board (DSMB), or potentially with other collaborators in the future. It is not yet determined if there will be a plan to make the IPD available.

The research staff performing the statistical analyses of the outcomes of interest will be masked from knowing the individuals' randomized treatment assignments, as will the principal investigator.