Uptake of carbon monoxide in Los Angeles commuters.

The uptake of carbon monoxide in Los Angeles commuters was measured by determining carbon monoxide concentrations in expired air before and after commuting. Estimates of exposure were made by determining carbon monoxide concentration in air collected within each car during each trip. There was a definite increase in expired air carbon monoxide concentration during the morning commute trip, but not during the afternoon trip. No consistent differences by geographic area were noted. Multiple correlation analysis showed that the post-commuting values depended more upon precommuting expired air values than upon carbon monoxide measured within the car. Smokers showed consistently higher values of carbon monoxide than nonsmokers, and the effect of smoking was several times greater than that of exposure to carbon monoxide levels experienced during commuting.