In airborne measurements in the vicinity of Barrow, Alaska and over the Beaufort and Chukchi Seas visible hazes were found in layers typically hundreds of meters thick and extending 20-200 km horizontally. Volume distributions of the particles in the hazes had distinct peaks in the accumulation and coarse particle modes at 0.25, 0.6 and 4 &mgr;m diameter. The principal aerosol component of the hazes was sulfate and this was associated with the accumulation mode.