sidestream smoke

synonyms: environmental tobacco smoke (ETS), secondhand smoke
https://doi.org/10.1351/goldbook.16088
Cloud of small particles and gases that is given off from the end of a burning tobacco product (cigarette, pipe, cigar) between puffs and is not directly inhaled by the smoker.
Note: This is the smoke that gives rise to passive inhalation on the part of bystanders.
Source:
PAC, 2007, 79, 1153. (Glossary of terms used in toxicology, 2nd edition (IUPAC Recommendations 2007)) on page 1309 [Terms] [Paper]