Puffing topography: a tool to evaluate vaping behavior and exposure risks.

The ever-changing popularity of electronic nicotine delivery systems (ENDS) among both youth and adults in the United States has been influential in shaping users' perceptions and behaviors. This behavior driven ENDS usage is described as puffing topography (PT) which includes user's puff duration, flow rate, intra puff interval, the volume of e-liquid used and total number of puffs per session. These metrics are not only useful for characterizing individual vaping behaviors but are also critical for assessing the extent of exposure to potentially harmful substances such as nicotine, volatile organic compounds (VOCs), and particulate matter emitted during use. Previous studies have indicated that puff volume and flow rate are distinct but related parameters that determine exposure to hazardous emissions among users and bystanders. However, current evidence suggests that vaping behavior is also influenced by the age at which users first encounter ENDS, the strength of the nicotine present, and whether users develop circadian patterns of ENDS usage. This review article, which is a part of the Special Issue Science Education and Research on Vaping and Interventions for Community Engagement summarizes the critical aspects of PT and explores how various factors including lifestyle, gender, e-liquid composition (such as flavor and nicotine concentration), and device parameters can influence exposure risks. The standardization of puffing topography as a tool to evaluate vaping behavior and exposure risks to toxic emissions could be instrumental in developing consensus standards for ENDS and protecting public health.