Industrial processes
			Petro-			Storage	Waste
	Chemical	Metals	leum	Other	Solvent	and	disposal	Total
	indus-	pro-	indus-	indus-	utili-	trans-	and	indus-
Year	tries	cessing	tries	tries	zation	port	recycling	trial
	million tons
1940	0.884	0.325	0.571	0.130	1.971	0.639	0.990	5.510
1950	1.324	0.442	0.548	0.184	3.679	1.218	1.104	8.499
1960	0.991	0.342	1.034	0.202	4.403	1.762	1.546	10.280
1970	1.341	0.394	1.194	0.270	7.174	1.954	1.984	14.311
1980	1.595	0.273	1.440	0.237	6.584	1.975	0.758	12.861
1989	0.980	0.074	0.639	0.403	5.964	1.753	0.941	10.755
1990	0.634	0.122	0.612	0.401	5.750	1.495	0.986	10.000
1991	0.710	0.123	0.640	0.391	5.782	1.532	0.999	10.178
1992	0.715	0.124	0.632	0.414	5.901	1.583	1.010	10.380
1993	0.701	0.124	0.649	0.442	6.016	1.600	1.046	10.578
1994	0.691	0.126	0.647	0.438	6.162	1.629	1.046	10.738
1995	0.660	0.125	0.642	0.450	6.183	1.652	1.067	10.780
1996	0.388	0.072	0.488	0.428	5.506	1.286	0.423	8.591
1997	0.390	0.076	0.499	0.444	5.654	1.324	0.427	8.812
1998	0.396	0.075	0.496	0.450	5.278	1.324	0.433	8.452
	Fuel combustion					Non-		Total
	Electric	Indus-			On-road	road	Miscel-	all
Year	utilities	trial	Other	Total	vehicles	sources	laneous	sources
	million tons
1940	0.002	0.108	1.867	1.977	4.817	0.778	4.079	17.161
1950	0.009	0.098	1.336	1.443	7.251	1.213	2.530	20.936
1960	0.009	0.106	0.768	0.883	10.506	1.215	1.573	24.459
1970	0.030	0.150	0.541	0.694	12.972	1.644	1.101	30.748
1980	0.045	0.157	0.848	1.050	8.979	2.141	1.134	26.166
1989	0.037	0.134	1.200	1.372	7.192	2.552	0.642	22.513
1990	0.047	0.182	0.776	1.005	6.313	2.545	1.073	20.936
1991	0.044	0.196	0.835	1.075	6.499	2.581	0.769	21.102
1992	0.044	0.187	0.884	1.114	6.072	2.594	0.500	20.659
1993	0.045	0.186	0.762	0.993	6.103	2.624	0.569	20.868
1994	0.045	0.196	0.748	0.989	6.401	2.672	0.734	21.535
1995	0.044	0.206	0.823	1.073	5.701	2.699	0.564	20.817
1996	0.049	0.166	0.821	1.036	5.490	2.664	0.954	18.736
1997	0.051	0.162	0.686	0.900	5.330	2.572	1.263	18.876
1998	0.054	0.161	0.678	0.893	5.325	2.461	0.785	17.917

Source:  U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards, National Air Quality and Emissions Trends Report, 1998, Table A-2 (EPA, OAQPS, Research Triangle Park, NC, 2000), and earlier reports in this series.

Notes:  na = not available. Non-road sources include non-road gasoline engines (e.g., lawn and garden and recreational marine vessels), non-road diesel (e.g., construction and farm), and aircraft. Miscellaneous includes fires, other combustion and natural geogenic sources.

Last Updated on Tuesday, May 2, 2000