Table 4-45:  Estimated National Emissions of Sulfur Dioxide (Million short tons),,,,,,,,,,,,,,,,,,,,,,,,,
,1970,1975,1980,1985,1986,1987,1988,1989,1990,1991,1992,1993,1994,1995,1996,1997,1998,1999,2000,2001,2002,,,,
TOTAL all sources,31.22,28.04,25.93,23.31,22.52,22.27,22.69,22.81,23.08,22.38,22.08,21.77,21.35,18.62,18.39,18.84,18.94,(R) 17.55,(R) 16.35,(R) 15.93,15.35,,,,
"Transportation, total",0.51,0.57,0.63,0.69,0.71,0.72,0.72,0.73,0.73,0.70,0.67,0.63,0.60,0.56,0.53,0.54,0.53,0.54,0.49,(R) 0.47,0.49,,,,
On-road vehicles,0.27,0.33,0.39,0.46,0.47,0.48,0.49,0.50,0.50,0.47,0.44,0.40,0.37,0.34,0.30,0.30,0.30,0.30,0.26,(R) 0.25,0.28,,,,
"Off-road, total",0.24,0.24,0.24,0.24,0.24,0.24,0.24,0.23,0.23,0.23,0.23,0.23,0.23,0.23,0.23,0.23,0.23,0.24,0.23,(R) 0.23,0.22,,,,
Aircraft,<0.01,<0.01,<0.01,<0.01,<0.01,<0.01,<0.01,<0.01,<0.01,<0.01,<0.01,<0.01,<0.01,<0.01,<0.01,<0.01,<0.01,<0.01,<0.01,<0.01,<0.01,,,,
Railroads,0.08,0.07,0.07,0.06,0.06,0.05,0.05,0.06,0.06,0.06,0.06,0.06,0.06,0.06,0.06,0.06,0.06,0.06,0.06,0.06,0.05,,,,
Marine vessels,0.16,0.16,0.16,0.17,0.18,0.18,0.18,0.17,0.17,0.17,0.17,0.16,0.16,0.16,0.16,0.17,0.17,0.18,0.16,0.16,0.16,,,,
"Nontransportation, total",30.70,27.47,25.30,22.61,21.81,21.54,21.97,22.08,22.34,21.68,21.42,21.14,20.75,18.06,17.86,18.30,18.41,(R) 17.00,(R) 15.86,(R) 15.46,14.86,,,,
Fuel combustion,23.46,22.66,21.39,20.02,19.43,19.43,19.76,19.92,20.29,19.80,19.49,19.25,18.89,16.23,16.25,16.65,16.74,(R) 15.34,(R) 14.16,(R) 13.74,13.17,,,,
Industrial processesa,7.09,4.68,3.77,2.43,2.22,1.94,2.02,1.98,1.86,1.68,1.72,1.65,1.62,1.59,1.37,1.43,1.43,(R) 1.33,(R) 1.38,(R) 1.43,1.37,,,,
Waste disposal and recycling,0.01,0.05,0.03,0.03,0.04,0.04,0.04,0.04,0.04,0.04,0.04,0.07,0.06,0.05,0.03,0.03,0.03,0.03,0.03,0.04,0.03,,,,
Miscellaneousb,0.15,0.08,0.10,0.13,0.13,0.14,0.16,0.15,0.15,0.16,0.17,0.17,0.19,0.19,0.20,0.20,0.20,(R) 0.30,(R) 0.28,(R) 0.26,0.30,,,,
KEY:  R = revised.,,,,,,,,,,,,,,,,,,,,,,,,,
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"a  Industrial processes comprises chemical and allied product manufacturing, metals processing, petroleum and related industries, and other industrial processes; solvent utilization; and storage and transport. ",,,,,,,,,,,,,,,,,,,,,,,,
"b  Miscellaneous comprises nontransportation-related fugitive dust, agriculture and forestry, nonroad gasoline, nonroad diesel, other nonroad sources and other miscellaneous combustion that could not be accurately allocated to specific source categories. ",,,,,,,,,,,,,,,,,,,,,,,,
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NOTES,,,,,,,,,,,,,,,,,,,,,,,,
"The methodologies used to estimate emissions constantly evolve and undergo major changes.  These improved methods are often used to revise estimates for previous years and, therefore, some estimates in this table may not match estimates produced in previous reports.  ",,,,,,,,,,,,,,,,,,,,,,,,
Numbers may not add to totals due to rounding.,,,,,,,,,,,,,,,,,,,,,,,,
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SOURCE,,,,,,,,,,,,,,,,,,,,,,,,
"1970-2002: U.S. Environmental Protection Agency, Clearinghouse for Inventories and Emissions Factors (CHIEF), Current Emission Trends Summaries, Internet website http://www.epa.gov/ttn/chief/trends/ as of Dec. 21, 2004.  ",,,,,,,,,,,,,,,,,,,,,,,,
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