Annual Sulfur Deposition in Maine

Gordon, Norma

'Precipitation in the northeastern United States and eastern Canada is more acidic than normal. Monitoring data collected in Maine since 1979 indicates moderately acidified precipitation with recorded annual average pH as low as 4.35 (Gordon et al. 1985). The major component of acidic precipitation in Maine and in the eastern United States is sulfuric acid. This acid forms when sulfur dioxide (SO2) released from electric utilities, industrial and smelting processes, and combustion of fossil fuels combine with moisture in the atmosphere. Because SO2 emissions in Maine are relatively low compared with those in the remainder of the United States and Canada, sources outside the State are expected to be the major cause of acidic deposition within Maine.' Estimated relative contributions of 1980 SO2 emissions from various source regions to sulfur deposition in Maine. The midwest area made relatively large contributions to sulfur deposition in Maine. Modeling was also performed to determine the effect of SO2 emission reductions in Maine on sulfur deposition. Annual sulfate deposition was calculated from measured data collected at Caribou, Greenville, Bar Harbor, and Bridgton.' /STUDY LOCATIONS:/ /ACADIA NATIONAL PARK/