The power plant produces aerosols that, in a clean atmosphere, enhance the concentration of particles of sizes smaller than 0.1 &mgr;m by more than two orders of magnitude, and of sizes larger than 1.0 &mgr;m by about a factor of ten. After two days of stagnant atmospheric conditions, ambient aerosol concentrations reach plume proportions. The plume-related aerosol has no effect on the threshold temperature of the freezing of supercooled water.