Campaigners claim more than 17,000 children aged under five in the UK are admitted to hospitals every year because of illnesses caused by breathing in secondhand smoke.
The annual meeting of the Scottish Tobacco Control Alliance in Glasgow also heard around half of all youngsters in the UK are now exposed to secondhand smoke (SHS) in their homes.
The event brings together health promotion, smoking cessation and tobacco control professionals to discuss ways to reduce the impact of tobacco on Scotland's health.
A survey of 2,040 adults in England and Scotland also reveals many parents have a worrying lack of knowledge about the dangers of smoking.
Around 26% identified asthma as a likely impact, and 22% mentioned respiratory illness or lung infections as an outcome.
But only 3% of parents know that cot death can result from SHS exposure, and only 1% identified glue ear as a potential problem.
Maureen Moore, chief executive of ASH Scotland, said: "Preventing exposure to SHS at home should be a public health priority if we are to protect our children's health from the dangers of tobacco.
"Children and infants face the highest levels of exposure to SHS in their own homes.
"Their smaller airways, faster breathing rates and immature immune systems make them more vulnerable to SHS than adults, and exposure to SHS in childhood is associated with Sudden Infant Death Syndrome, asthma, reduced lung function, middle ear disease, an increased risk of a range of respiratory symptoms, and a higher incidence of respiratory tract infections including bronchitis, bronchiolitis, croup, and pneumonia."