Short-term particulate matter mass and aerosol-size distribution measurements: transient pollution episodes and bimodal aerosol-mass distributions

Aerosol-size distribution of fine aerosols were measured in Pocatello, Idaho along with hourly average PM10 mass concentrations. Aerosol size distribution measurements are made with a laser optical particle counter while short-term mass concentrations are measured with a Tapered Element Oscillating Microbalance. The short-term mass concentration measurements show wide variations in mass concentration over 24 h periods. The accumulation mode of the aerosol-size distribution is bimodal in a few cases, primarily when elevated mass concentrations exist.