February 5, 2008
SMOKE EXPOSURE IN CARS
Amy Movius MD
By now, most Mainers are aware of the Bangor law prohibiting smoking in cars when children are present. A proposal to extend this ban statewide is currently before the Maine Legislature and may be enacted into law soon.
This issue has raised concerns about individual civil rights in what is clearly a medical issue for children. Child car seats are required for children to protect them in event of an accident. Exposure to second hand smoke in a car is harmful to children, and reducing that exposure will help to protect them from illness.
Respirable suspended particles, or RSPs, are small toxic particles generated in the thousands by cigarette smoke. These particles penetrate deeply into the lungs. Measurement of toxic levels of RSPs in public places is what led to the ban on smoking in restaurants, bars and the like. According to the Environmental Protection Agency, an RSP level at or above 250 ug/m3 is harmful to everyone. However, the harmful level for “sensitive groups” such as children, is much lower at 40 ug/m3. That is because young, developing lungs are easier to injure than more mature lungs.
Studies done on the level of RSPs produced in cars by even one cigarette have demonstated production of RSPs in levels greater than the EPAs hazardous threshold of 250 ug/m3, which is already more than four times the toxic threshold for children. These RSP levels occur within minutes of lighting a cigarette and are present with the windows open or cracked. I recently took a drive with Dr Jonathan Shenkin and an expert from the University of Maine during which Dr. Shenkin smoked a cigarette. The identical equipment to that used in the formal studies was placed in a backseat child’s car seat. It happened to be a very cold Maine winter day, with temperatures in the single digits. Thus, we left the windows closed. In mere seconds, the RSP measurement was greater than 1000 ug/m3. This is 4X greater than levels determined to be dangerous to all, and 25X greater than the level toxic to children.
Reduction in environmental smoke reduces the number of the environmental toxins that get into children and others who breathe in second hand smoke. Institution of public smoking restrictions in public places has had measurable benefits for adult nonsmokers. In the Surgeon Generals July 2006 report, measurement of urine cotinine (a nicotine by-product) was significantly decreased in adult nonsmokers when compared to levels before the ban. However, these benefits do not extend to children. This is likely because children are mostly exposed to second-hand smoke in domestic locations such as cars and homes.
There is no question that secondhand smoke exposure can be harmful. In children, secondhand smoke has been linked to increased lower respiratory infections such as pneumonia, Sudden Infant Death Syndrome, ear infections and worsening asthma. These are the same reasons it is illegal for children to buy and smoke cigarettes.
Given the lack of benefit to children from previous smoking restrictions and the astounding research on just how toxic the levels of second hand smoke found in cars can be, the healthcare community has a responsibility to increase awareness of the danger to child passengers. Again, this is not unlike child car-seat laws. At the end of the day, the only intention of this law is to protect Maine’s children.
Surgeon Generals Report on Second Hand Smoke, July 2006
Rees and Connolly. Measuring Air Quality to Protect Children from Secondhand Smoke in Cars, American Journal of Preventive Medicine, 2006.
Ott, Klepeis, Switter. Air Change Rate of Motor Vehicles and In-Vehicle Pollutant Concentrations From Secondhand Smoke. Jounal of Exposure Science and Environmental Epidemiology, July 2007