Define mainstream smoke

Answer 1

Mainstream smoke is a combination of inhaled and exhaled smoke after taking a puff on a lit cigarette. The composition of mainstream smoke is affected by how the smoker inhales and exhales, so it will vary from person to person. The frequency of puffs, duration and volume all contribute to the makeup of mainstream smoke

Answer 2

Main-stream smoke is smoke that the actual person smoking inhales then exhales!