Additional Study Information: The use of electronic cigarettes, also known as e-cigs or vaping, has increased among former smokers and young adults who have never smoked. Relatively little is known, however, about their health effects (whether they are adverse, have no effect, or are beneficial). The purpose of this research study is to evaluate (1) the association of e-cig use with metal exposure, (2) whether e-cig use is associated with buildup of calcium in the arteries and other vascular parameters, (3) whether e-cig use is associated with changes in lung structure and function and (4) whether the metals contained in e-cigarette aerosols are associated with changes in vascular and lung structure and function. The first visit generally last about 1-1 hours, but could take up to 4 hours if you schedule the CT scan on the same day, because you will need to travel to Mt. Sinai Medical Center for the scan. If you are interested in the MRI portion of the study, that will be scheduled separately. The second visit will take place at 9-12 months and the third visit at 18-24 months after the initial visit and will again take about 1-1 hours. If you complete all study procedures you will be compensated up to $650 in the form of e-gift cards or registered paycards. If you are not eligible or decline to participate in the MRI, but complete the other lung components of the study, you will receive up to $450 compensation. If you decide to participate, your involvement in the study will last eighteen to twenty-four months. You can decline participation at any time. The VapeScan Study pre-screener can be found at: https://www.sac-cu.org/vapescan/public/screen.aspxor https://bit.ly/vapescan. If you know other people interested in participating please feel free to forward the information about this study.