In patients with chronic obstructive pulmonary disease (COPD), passive vape exposure from e-cigarettes has been shown to be potentially harmful by exerting acute small inflammatory responses in the lungs and blood, as well as throat irritation. [...] The researchers sought to explore the local and systemic effects of short-term passive vape exposure among individuals with mild or moderate COPD. A randomized, controlled, double-blind, crossover study on the topic was conducted in Denmark. All of the participants were subjected to 2 exposure sessions. [...]