The Rate of SO₂ to Sulfate Particle Formation in an Air Parcel from an Oil Sands Extraction Plant Plume

Abstract

A field program was conducted to determine the transformation of sulfur dioxide to particulate sulfate in the emissions from oil sands extraction plants near Fort McMurray, Alberta. Measurements were made under cold winter conditions during March and December 1983 and warm summer conditions during June 1984. The transformation rates of SO₂ to SO₄ were determined by tracking a single parcel of air emitted from the stack using an instrumented aircraft. Two methods were employed: the aerosol excess volume production and chemical analysis of particles collected on filters. The conversion rate varied from 0 to 2.81 percent per hour in the winter and 0 to 6.01 percent per hour in the summer. The significant oxidation of SO₂ to SO₄ observed during wintertime and early morning periods in the summer, and the considerable amounts of excess aerosol volume production of particles larger than 1.0 μm suggest that heterogeneous conversion may be appreciable close to the emission source, when the SO₂ and aerosol concentrations are high and the aerosol surface is wet.