The types of chemicals released into the air when people smoke and the length of time these chemicals may linger indoors depends on several product and building factors, including type of product used, how much is used, how long it is used, the room size, amount of ventilation in the area, and surfaces in the room. Not seeing or smelling smoke does not mean that there are no chemicals from smoking still in the air or space that can potentially cause health problems, especially for some sensitive groups like children.
Read more about Secondhand Smoke/Aerosol.