Smoking outside may not protect those indoorsParents who smoke outdoors still expose homes and kids to nicotine.
HELEN R. PILCHER
Parents who chose not to smoke inside the family home may still be subjecting their children to the effects of passive smoking, a study suggests.
Nicotine, a major ingredient of secondhand smoke, can be detected in the dust and air inside the homes of smokers who deliberately go outside for a puff. Children in such homes have up to eight times more nicotine in their bodies than the offspring of non-smokers1.
The levels of nicotine are still quite low, says Georg Matt from San Diego State University, California, who led the study. But they could build over time, potentially making the children more prone to smoking-related problems, such as asthma and sudden infant death syndrome.
Cigarette fumes probably become lodged on the hair and clothes of parents as they smoke outside, says Matt. The particles could then be brought back inside the house, where they would hang in the air or settle in dust. Family members may then inhale them directly or unwittingly transfer them from hand to mouth.
Infants are particularly at risk as they spend most of their time indoors and often put objects into their mouths, says Matt. Contaminated dust can settle on toys, carpets and bedding and may remain there for months, he adds.
"The study shows that parents can reduce the amount of passive smoke inhaled by their children by always smoking outdoors," says Matt. "But they would be mistaken to think that this completely protects their children from exposure."
Matt's team looked at 49 family homes with children less than one year-old. Fifteen homes were occupied by non-smokers. The remainder were split between indoor and outdoor smokers.
The researchers assessed nicotine levels in urine samples from the children, and in dust and air samples taken from the children's bedrooms and living rooms.
The children of indoor smokers had the highest nicotine levels of all - up to eight times more than outdoor smokers' children, and up to 14 times more than those of non-smokers. Levels of nicotine in dust and air followed a similar pattern.
If nicotine is present, then other, more harmful chemicals from cigarette smoke are also likely to be there, says tobacco researcher Martin Jarvis from University College London.
Cigarette smoke is a complex mix of some 4000 chemicals. Many of these, such as formaldehyde, ammonia and hydrogen cyanide are harmful to human health.
It is still unclear exactly how the nicotine finds its way into the homes of outdoor smokers, says Matt. As well as sticking to clothes, smoke could be entering the house more directly, he says.
During the study, a few of the outdoor smokers admitted to the occasional indoor cigarette. Other parents may also have smoked indoors, but been unwilling to admit it, says Jarvis. So some infants, whose parents claim to smoke outside, may have inhaled second-hand smoke directly.
Contaminated dust could also be left over from previous smoking occupants, says Matt. "Before you buy a used car, rent an apartment or a house, you may want to inquire about the smoking habits of the former owners or renters," he says.
© Nature News Service / Macmillan Magazines Ltd 2004
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