ASH Scotland said hundreds of thousands of deaths every year are caused by the problem and that should be evidence enough to push for stricter smoking laws.
Chief executive Sheila Duffy said: "Although we have made great progress in Scotland by making public places smoke-free, exposure to this poisonous substance is still commonplace in homes and cars.
"Children can be particularly badly affected by exposure to tobacco smoke, increasing their risk of developing respiratory problems and other conditions.
"In Scotland around 300,000 pre-teen children live with at least one parent who smokes.
"Because we know second-hand smoke can cause so many avoidable health problems, reducing exposure must be a priority."