sidestream smoke; secondhand smoke
Refers specifically to smoke that comes directly from the burning end of a cigarette, as opposed to mainstream smoke (主流煙) exhaled by the smoker. Often discussed in the context of passive smoking.
See also: 主流煙
Sidestream smoke contains many harmful substances.
副流煙による受動喫煙が問題になっている。
Passive smoking from sidestream smoke has become a problem.