Sources and concentrations of indoor XXXX in Barcelona, Spain.

@entity1 @entity7459 @entity6836
Sources and concentrations of indoor @entity7459 ( @entity6836 ) were examined in Barcelona, Spain, during 1996-1999. A total of 340 dwellings of @entity1 participating in a hospital-based cohort study were selected from different areas of the city. Passive filter badges were used for indoor @entity6836 measurement over 7-30 days. Dwelling inhabitants completed a questionnaire on housing characteristics and smoking habits. Data on outdoor @entity6836 concentrations were available for the entire period of the study in the areas of the city where indoor concentrations were determined. Bivariate analysis was performed to investigate relationships between indoor @entity6836 concentrations on one hand and outdoor @entity6836 concentrations, housing, and occupant characteristics on the other. Stepwise multiple linear regression was performed with variables that were found to have a significant bivariate relationship. Indoor @entity6836 mean values ranged between 23.57 ppb in 1996 and 27.02 ppb in 1999, with the highest yearly value of 27.82 ppb in 1997. In the same time period, mean outdoor @entity6836 concentration ranged between 25.26 and 25.78 ppb with a peak of 30.5 ppb in 1998. Multiple regression analysis showed that principal sources of indoor @entity6836 concentrations were the use of a gas cooker, the absence of an extractor fan when cooking, and cigarette smoking. The absence of central heating was also associated with higher @entity6836 concentrations. Finally, each ppb increase in outdoor @entity6836 was associated with a 1% increase in indoor concentrations.
