Carboxyhaemoglobin levels of car occupants commuting in an urban commercial/residential area

Biological carbon monoxide (CO) monitoring is a direct approach to assess CO exposure and associated potential health impacts. Exhaled breath CO concentrations and corresponding carboxyhaemoglobin (COHb) level of car occupants were measured before and after 45-min in-vehicle commutes along a congested road in a typical commercial/residential area using various ventilation modes. The effects of longer commutes were examined by fitting the measured in-vehicle mean CO levels with the Peterson and Stewart model for COHb level prediction. The increase in COHb level after a trip varied from 0 to 57% for a non-smoker passenger. Predicted COHb levels indicate that potential health outcomes can be manifested for trips lasting more than 70 min and characterized with low in-vehicle air exchange.