Variance components of indoor and outdoor VOC concentrations


Concentrations of airborne volatile organic compounds (VOCs) can vary tremendously in both indoor and outdoor environments, yet few studies have quantitatively partitioned the variability. Using VOC concentrations measured inside and outside of 162 residences in three industrial, urban and suburban communities in southeast Michigan, U.S.A., the variance of concentrations is apportioned across cities, between homes, between seasons, and between replicate measurements using mixed-models. In indoor environments, measurement uncertainty contributed less than 20% of the indoor variances, thus measurements were highly reproducible. Between-home and seasonal variances contributed 34 and 54%, respectively, of the total variance. Across-city variation was small, suggesting that neighborhood effects were insignificant. For outdoor concentrations, different patterns emerged: variance components were generally ranked as seasonal > between-replicate > across city > across-site. Thus, ambient VOCs displayed strong seasonal and neighbourhood effects. Measurement uncertainties occurring at low concentrations may confound the other factors.

Publication Title

12th International Conference on Indoor Air Quality and Climate 2011

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