Smoking in Cars: Polluting Kids

Secondhand smoke inside the closed space of a car concentrates pollutants

/ Author:  / Reviewed by: Robert Carlson, M.D

(RxWiki News) Smoking in the car is only bad if the windows are up, right? Think again! Scientists found extreme pollutants from secondhand smoke in the backseat even with the front windows completely down.

A recent study tested pollutants from a person smoking three cigarettes in one hour inside a stationary car with the windows down. In the back seat for just 10 minutes, a child’s exposure to harmful pollutants increased by 30 percent.

Authors said, “Children are more vulnerable than adults, and their exposures to tobacco smoke in a vehicle are completely controlled by the adults with whom they share the vehicle.”

"Never smoke with a kid in the car."

Amanda Northcross, PhD, from the School of Public Health at the University of California at Berkley, led researchers to investigate secondhand smoke in cars.

For the study, a volunteer smoked three cigarettes in one hour inside a stationary car for 22 separate experiments. Researchers measured levels of fine particulate matter (PM2.5), polycyclic aromatic hydrocarbons (PAH), carbon monoxide (CO) and nicotine. All are pollutants found in secondhand smoke.

Pollutants were measured from a child’s height in the back seat of the car. The experiment included measurements with the front windows completely down or with the windows down 10 cm. Test results showed the PM2.5 average size was 0.3 micrometers. PM2.5 inside the open windowed car was 746.1 micrograms per square meter. PM2.5 inside the 10 cm cracked window was 1172.1 micrograms per square meter.

Nicotine levels were 5.06 micrograms per square meter with the windows down and 411.3 micrograms per square meter with the windows cracked 10 cm. CO levels averaged 2.8 parts per million once the cigarettes were put out. PAH levels were 10 times higher inside the car.

Authors found that for a child, 10 minutes in the backseat of a car where a person is smoking a cigarette increases exposure to PM2.5 by 30 percent with 10 cm cracked windows and 18 percent with totally open windows.

Authors said, “Even short exposure periods are capable of creating large exposure to smoke.”

“Although regulations have been enacted to protect non-smokers, including children in many public venues, secondhand smoke exposure to children in vehicles is permitted in 44 of 50 US states, and in most countries worldwide.”

The Environmental Protection Agency (EPA) monitors PM2.5. The EPA advises standard PM2.5 levels should be average less than 15.0 micrograms per square meter.

Secondhand smoke inside small, contained areas like cars has higher concentrations of pollutants than in other indoor areas like homes, restaurants, bars and casinos, according to the study.

This study was published in November in Tobacco Control. No funding information was provided. No conflicts of interest were reported.

Reviewed by: 
Review Date: 
December 4, 2012
Last Updated:
February 22, 2013