MEASUREMENT OF PERSONAL EXPOSURE TO NO2 IN SWEDEN - EVALUATION OF A PASSIVE SAMPLER

A passive (filter badge) sampler for personal NO2 exposure measurements was tested in a laboratory setting (exposure chamber), and in the field - outdoors, during periods of high relative humidity (mean 85%) and low temperature (-5 to +10-degrees-C), and indoors, in an ice-hockey arena - using chemiluminescence as a reference method. Parallel measurements of NO2 in the exposure chamber (concentration range 100-825 mug NO2/m3) for 15, 30, and 60 min sampling periods, showed good agreement between methods. The concentrations obtained with passive samplers were 78 to 122% (mean 94%, SD +/-11, N = 39) of those obtained with chemiluminescence, using a sampling rate (K'OG) of 0.14 cm/sec. The detection limits were 320, 160, and 80 mug NO2/m3 for 15, 30, and 60 minutes of sampling, respectively. Outdoors (concentration range 15-102 mug NO2/m3, concentrations obtained with passive samplers were consistently lower than concentrations obtained with chemiluminescence (mean 79%, SD +/-9.3%, range 61-95%, N = 25), using the K'OG of 0.14 of cm/sec (Passive samplerNO2 = 0.67ChemilumNO2 + 4-5). A better agreement between concentrations obtained with passive samplers and chemiluminescence was achieved with a K'OG Of 0.11 cm/sec (mean 100%, SD +/-12%, range 78-121%, Passive samplerNO2 = 0.84ChemilumNO2 + 6.4). Indoors (concentration range 210-3895 mug NO2/m3), concentrations obtained with passive samplers were 70 to 113% (mean 90%, SD +/-16%) of the concentrations obtained with chemiluminescence (Passive samplerNO2 = 1.00ChemilumNO2 - 93) using a K'OG Of 0.10 cm/sec. Duplicate samples collected indoors N = 18) and outdoors (N = 31) showed a variability (coefficient of variation, or CV) of less than 6%. It was concluded that the passive sampler is useful for measuring personal daily exposure as well as peak exposure. It is necessary to determine sampling rates for various environmental conditions.