VISIBILITY AND AEROSOL COMPOSITION IN THE FRASER VALLEY DURING REVEAL

During July and August 1993, the Regional Visibility Experimental Asse ssment in the Lower Eraser Valley (REVEAL) field program was conducted to examine aerosol composition and visibility in the Eraser Valley, B ritish Columbia. The field program involved monitoring three elements of atmospheric visibility - aerosol characteristics (using IMPROVE aer osol samplers and a DRUM sampler); optical characteristics (using neph elometers and a long path transmissometer); and scene characteristics (using automated camera systems). A preliminary assessment of the data collected during REVEAL indicates that visibility and aerosol concent rations and composition are highly variable in the temporal and spatia l dimensions, and while organic matter dominates fine aerosol mass (ac counting for 35-46% of the mean fine aerosol mass), nitrates and sulfa tes dominate particle light scattering (b(sp)) (accounting for 55-67% of mean b(sp)).