Even `third-hand` smoke kills

London: Have you finally amended your habits and stopped smoking inside the house to protect your kids from exposure to second-hand smoke? That may not be good enough!

Researchers have found that even 'third-hand' smoke, tobacco smoke gases and particles deposited as dust in homes, pose a potential cancer risk to non-smokers, particularly young children.

"The risks of tobacco exposure do not end when a cigarette is extinguished. Non-smokers, especially children, are also at risk through contact with surfaces and dust contaminated with residual smoke gases and particles, the so-called third-hand smoke," explained Jacqueline Hamilton from University of York in Britain.

"This risk should not be overlooked and its impact should be included in future educational programs and tobacco-related public health policies," Hamilton added.

The study demonstrated for the first time the widespread presence of tobacco related carcinogens in house dust, even in "smoke-free" environments.

Scientists collected dust samples from private homes occupied by both smokers and non-smokers. Using observations of house dust composition, they estimated the cancer risk by applying the most recent official toxicology information.

They found that for children aged one to six years, the cancer risks exceeded the limit recommended by the US Environmental Protection Agency (EPA) in three quarters of smokers' homes and two thirds of non-smokers' homes.

The study was published in the journal Environment International.