Two-zone modelling for air exchange rates and NO/sub 2/ source and decay rates in a Southern California residential indoor air quality study

BNL/AIMS and NO/sub 2/ measurements were applied to 640 homes in Southern California during March 1984, July 1984, and January 1985. Whole house AERs had median values of 0.84/h, 1.5/h and 0.55/h respectively. NO/sub 2/ decay rates for 18 all-electric homes, and for the bedroom zone across all homes, had a median of about 0.6/h and did not vary noticeably among test periods. Median NO/sub 2/ source rates for the living zone (kitchen and living room) were 10.6 mg/h, 12.3 mg/h and 7.4 mg/h, while medians for the bedroom zone were all 0 mg/h. Outdoor sources made the largest contribution to NO/sub 2/ in the bedroom zone, while indoor sources were marginally more important than outdoor in the living zone (Southern California has high concentrations of outdoor NO/sub 2/).