Visibility and aerosol composition in the Fraser Valley during REVEAL

During July and August 1993, the Regional Visibility Experimental Assessment in the Lower Eraser Valley (REVEAL) field program was conducted to examine aerosol composition and visibility in the Eraser Valley, British Columbia. The field program involved monitoring three elements of atmospheric visibility - aerosol characteristics (using IMPROVE aerosol samplers and a DRUM sampler); optical characteristics (using nephelometers 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 concentrations and composition are highly variable in the temporal and spatial dimensions, and while organic matter dominates fine aerosol mass (accounting for 35-46% of the mean fine aerosol mass), nitrates and sulfates dominate particle light scattering (b(sp)) (accounting for 55-67% of mean b(sp)).