TRENDS IN US PULP AND PAPER-MILL SO2 AND NOX EMISSIONS, 1980-1995

Emissions of sulfur dioxide and nitrogen oxides from U.S. pulp and pap er mills for 1980, 1985, 1990, and 1995 were estimated from industry-w ide surveys. The results showed SO2 emissions decreased by 45% from 87 5,000 tons in 1980 to 480,000 tons in 1995. Coal and residual oil burn ing in boilers and combustion of spent kraft pulping liquor in recover y furnaces were the main sources of SO2 emissions. Reductions resulted from use of lower sulfur coal and residual oil, reduced consumption o f residual oil, growing use of SO2 controls on boilers and kraft mill thermal oxidizers, and increased use of nondirect contact kraft recove ry furnaces with minimal SO2 emissions. NOx emissions from pulp and pa per mills increased by 15% from 275,000 tons in 1980 to 316,000 tons i n 1995 with most increase occurring between 1980 and 1985. Burning of coal, natural gas, and kraft black liquor was the main source of NOx e missions. The reductions in SO2 emissions and modest increase in NOx e missions from 1980 to 1995 occurred despite an increase of paper and p aperboard production of 47% and a 41% rise in kraft pulp production ov er the same period In 1995, pulp and paper mill emissions represented approximately 2.5% of the total national SO2 emissions and 1.5% of the total NOx emissions.