Measurement of indoor-outdoor carbonyls at four residential homes in Mexico City metropolitan area

Formaldehyde, acetaldehyde, acetone, propionaldehyde and butyraldehyde were measured in indoor and outdoor air at three houses and one apartment in the Mexico city metropolitan area (MCMA). Formaldehyde presented the highest concentration in indoor and outdoor air, followed by acetone and acetaldehyde. Indoor carbonyl concentrations were higher than outdoor concentrations at all sampling sites. Indoor exposure factors were estimated for formaldehyde and acetaldehyde, ranging from 202 µg day–1 to 554 µg day–1 for formaldehyde and from 82 µg day–1 to 202 µg day–1 for acetaldehyde. Indoor-outdoor correlations were significant at all sites. However, these correlations were the highest in the Miguel Hidalgo house, which was naturally well ventilated, and where very few activities like cooking, were done. Concerning the Tlalnepantla house, although it was also well ventilated, the correlations were not as high as those observed at the Miguel Hidalgo house, possibly because its inhabitants cook a lot more and throughout the whole day.