What is the difference between mainstream smoke and sidestream smoke?

What is mainstream smoke?

 A smoker that inhales the smoke and exhales the smoke into the environment is called mainstream smoke. 

What is sidestream smoke?

Smoke that is released into the environment from a burning cigarette is called sidestream smoke. 

What is the difference?

The difference between the both is that mainstream smoke is a smoker that inhales the smoke and exhales the smoke into the environment and sidestream smoke is Smoke that is released into the environment from a burning cigarette. 

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If it's a smaller child or infant, place one on the middle of the chest and on the child's back. (if it is a bigger child with enough room for two, place one on the upper right/your left of the chest, and one on the lower left/your right) the pads should never touch each other.