Particle size distributions from 9 to 640 nm diameter were measured at Eagle Ridge in the lower Fraser Valley from 13 August to 1 September 2001 as part of the Pacific 2001 Air Quality Study. The site was on top of a ridge, about 300 m above the valley floor, in a predominantly agricultural area about 70 km ESE of Vancouver. To further characterize the particles, their hygroscopic properties (a...