ASSESSMENT OF THE INFLUENCE OF CLIMATIC FACTORS ON CONCENTRATION LEVELS OF VOLATILE ORGANIC-COMPOUNDS (VOCS) IN CANADIAN HOMES

A nationwide study of indoor air concentrations of 26 VOCs was conducted in Canada in 1991. The study design was based upon random selection of private residences from 1986 Census data and incorporated a temporal stratification feature that allowed sampling of residences in each of four regions of the country at different times of the year with equal probability. Average 24 h concentrations of 26 VOCs in 754 residences were obtained by a passive monitoring method. Initially, climatic parameters were found to have the second highest relative weight among 14 factors identified by factor analysis. Further analysis by linear regression showed that individual VOC concentrations and average outdoor temperature or relative humidity were poorly correlated (r < 0.13). Detailed analysis of the data from four regions of Canada also gave poor correlations between household VOC concentrations and temperature or relative humidity. Concentrations of all 26 VOCs averaged 7.8 mu g m(-3) in winter, 10.3 mu g m(-3) in spring, 4.4 mu g m(-3) in summer and 10.8 mu g m(-3) in fall. The highest concentrations of individual compounds averaged 84 mu g m(-3) for toluene in the spring and 42 mu g m(-3) in the fall, and 44 mu g m(-3) for decane in the spring and 48 mu g m(-3) in the fall. Segregation of the results into outdoor temperature ranges of less than or equal to 0 degrees C, 0-15 and > 15 degrees C gave mean indoor VOC concentrations of 10.3, 9.8 and 50 mu g m(-3), respectively. Further examination of the results revealed that the likely presence of sources within homes had a far greater influence on indoor concentrations than ventilation which is partly influenced by climate.