Analysis of indoor concentrations of benzene using an air-quality model

We performed measurements to determine indoor benzene levels in 26 resident ial houses in Kuwait, located in zones of different activity levels. Pumped (or active) sampling was conducted via use of 12 sampling tubes over a per iod of 24 hr for both indoor and outdoor concentrations simultaneously. Tim e-average indoor concentration varied linearly with time-average outdoor co ncentration in accordance with a mass-balance-based indoor air-quality mode l in which source and sink terms were incorporated. We used regression anal ysis to determine benzene adsorption rates, which appear in the removal and source terms of the model. The removal rate parameter varied between 0.12/ hr and 2.16/hr, whereas source term parameter varied between 0.60 mg/hr and 76.07 mg/hr. Houses were then divided into three groups according to their benzene source strengths (i.e., < 1.0 mg/hr, 1-10 mg/hr, and 10-50 mg/hr). Qualitatively, these levels depended on the characteristics of occupants ( e.g., smoking and gas cooker use, number of cars, and parking area) and loc ation of the building.