A climatology of solid atmospheric contaminants at Aspendale, near Melbourne, Victoria, 1966 to 1971

Air concentrations of solid matter near the surface have been recorded on a routine weekly basis since 1966. These allow documentation of a gradual increase until late 1968, followed by a general decrease. Overall, the values found are lower than usually reported in urban situations. Particulate concentrations are found to be highest in conditions of light winds from the industrial areas located to the north and northwest. A correlation is found with mean maximum temperature, but no rainfall effect is found. Week-to-week dust concentrations are found to vary statistically by about 20% (one standard deviation) and on a monthly basis this figure reduces to about 10%. The particle mass spectrum is found to maximise at about 25 µm diameter, giving a mean sedimentation velocity of about 1.3 cms-1 which is supported by dustfall considerations. The average residence time of the dust observed at Aspendale appears to be of the order of 11hours.