The actual levels of ketene from commercial products will typically be lower than what we have determined herein since other ingredients will likely also be present in the starting products. For example, the commercial sample purchased and studied for this work contained equimolar amounts of ∆ 8 -THC-OAc and ∆ 8 -THC, as well as terpenes. In addition, vaping with an e-cigarette does not involve large inhalation volumes relative to dabbing, and ketene inhaled from a vape pen will be relatively more dilute in the lungs. In addition, ketene also can react with water in the upper respiratory tract to form acetic acid prior to reaching the lungs.