RATE OF OXIDATION OF SULFUR-DIOXIDE IN PLUME OF A NICKEL SMELTER STACK

Some results are presented on the rate of formation of sulfates from SO//2 in the plume of the 380 m stack at the INCO nickel smelter at Copper Cliff, Canada. The plume was sampled by aircraft, during September 1974 and June 1975, using glass fiber and chemically impregnated cellulose filters to collect aerosols and SO//2 respectively. It was found that within the first 100 km or so of the stack, usually less than 10% of the sulfur in the plume is in the form of sulfate. Oxidation rates were found to be similar in September 1974 and June 1975, and were generally less than 3%h** minus **1. No temperature or humidity effects could be detected in the data. The results did suggest a slight decrease in the oxidation rate with plume age, but the experimental scatter was too large to allow any definite conclusions. An average value of about 1%h** minus **1 seems to be representative.