A Birmingham hospital is urging parents to smoke less or quit to protect their newborn babies and children from the "festive fug".
Midwives at Good Hope Hospital, in Sutton Coldfield, are asking smokers to manage their habit as they are worried people spend so much time indoors over the festive period that children in the same room face a greater risk of passive smoking.
Second hand smoke contains more than 4,000 toxins - including 40 cancer-causing carcinogens - and more than four out of ten children in Britain live with at least one smoker in their home.
Now a second-hand smoke calculator has been devised which can work out how many toxic chemicals children's bodies would absorb if exposed to prolonged smoking in confined spaces.
A three-year-old child who spends an average of six hours in a room with three smokers can passively inhale more than 30 toxins including two carcinogens and harmful chemicals like arsenic, benzene and cyanide.
Even with one smoker in the room the child would still absorb 25 chemicals and toxins into their body.
Carmel O'Gorman, midwifery lead on the hospital's Smoking Cessation in Preg-nancy scheme, said: "Christmas is wonderful time for a family to be together.
"But if some of those family members are smokers they could generate a fug of smoke that will be filled with millions of billions of poisonous particles and potentially harmful toxins.
"We are urging parents, relatives and friends who smoke not to do so in a confined space that will build up a fug and puts children's lives in danger from second hand smoke."
It is estimated more than 17,000 children under the age of five are admitted to hospital every year in Britain with illnesses resulting from passive smoking.
Research has shown second-hand smoke is responsible for numerous conditions including cot death, meningitis, asthma, chest infections, ear infections, learning difficulties and behavioural problems, coughs, colds and wheezes.
But even when the visible smoke has cleared, harmful chemicals can remain suspended in the air as an invisible but potentially dangerous cocktail of toxins.
During December, all new parents - smokers and nonsmokers - at Good Hope's maternity unit are being given packs containing air fresheners, drink coasters, table cards and door/window stickers and bibs to promote the need to manage their habit around children.
To help beat the "festive fug" parents can encourage visitors to smoke outside and keep communal rooms smoke-free, not to smoke around children or while eating.
The initiative is part of the NHS second-hand smoke campaign and is supported by North Birmingham Primary Care Trust.
Ms O'Gorman added: "Home is the biggest source of second hand smoke. By making them smoke free the risk of illness and death will be reduced."
* For information on stopping smoking call North Birmingham NHS smoking cessation service on 0800 389 2808.
