This study is about home air radon testing and has two phases. The goal of the first phase is to learn about renters' and homeowners' views and plans related to radon testing. The main question this phase aims to answer is: 1\. Does taking part in a focus group with information about radon testing change people's plans to test for radon? Participants in the first study phase will: * Take a survey about their views on and plans for radon testing. * Take part in a focus group discussion about radon testing, during which they will receive information about radon testing. * Right after the focus group, take a survey about their plans for radon testing. The second phase is a pilot interventional study. The goal is to test interventions about radon testing with renters and homeowners who smoke and do not smoke. The main questions this phase aims to answer are: 1. Does the recruitment strategy result in enough participants enrolling within 3 months? 2. Will at least 80% of participants complete data collection activities? 3. Will more participants who view an online intervention developed by the researchers request free radon test kits, set them up in their homes, and complete radon testing, compared to participants who view a standard public health infographic? And will even more participants who receive reminder messages, in addition to the online intervention, request free radon test kits, set them up in their homes, and complete radon testing? Participants in this second phase will: * Take a survey about their views on and plans for radon testing. * View an intervention about radon testing. * Right after viewing the intervention, take a survey about their views on and plans for radon testing. * 2 months later, take a survey about what, if any, steps they've taken to test their homes for radon. * Provide the researchers permission to collect data from their State Radon Program on: a) whether they requested a free radon test kit and b) whether testing was completed. Some participants will receive reminder messages for 2 months after viewing the intervention. Researchers will compare an online intervention they developed about radon testing to: a) a standard public health infographic and b) their online intervention combined with reminder messages about radon testing. They will compare the interventions by proportion of participants who: a) request a free radon test kit from their State Radon Programs, b) set-up the radon test kit in their homes, and c) complete radon testing.