Carbon Monoxide (CO)

National Emission Trends (thousand short tons) 

Source Category 1970 1975 1980 1985 1990 1991

FUEL COMB. ELEC. UTIL. 237 276 322 291 363 349

FUEL COMB. INDUSTRIAL 770 763 750 670 879 920

FUEL COMB. OTHER 3,625 3,441 6,230 7,525 4,269 4,587

CHEMICAL & ALLIED PRODUCT MFG 3,397 2,204 2,151 1,845 1,183 1,127

METALS PROCESSING 3,644 2,496 2,246 2,223 2,640 2,571

PETROLEUM & RELATED INDUSTRIES 2,179 2,211 1,723 462 333 345

OTHER INDUSTRIAL PROCESSES 620 630 830 694 537 548

SOLVENT UTILIZATION NA NA NA 2 5 5

STORAGE & TRANSPORT NA NA NA 49 76 28

WASTE DISPOSAL & RECYCLING 7,059 3,230 2,300 1,941 1,079 1,116

HIGHWAY VEHICLES 163,231 153,555 143,827 134,187 110,255 104,980

OFF-HIGHWAY 11,371 14,329 16,685 19,029 21,447 21,934

MISCELLANEOUS 7,909 5,263 8,344 7,927 11,122 8,618

TOTAL 204,042 188,398 185,408 176,845 154,188 147,128
1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

350 363 370 372 408 423 451 496 484 485 657 652

955 1,043 1,041 1,056 1,188 1,162 1,151 1,213 1,219 1,253 1,267 1,229

4,849 4,181 4,108 4,506 2,741 2,742 2,727 3,829 3,081 3,088 3,550 3,477

1,112 1,093 1,171 1,223 1,053 1,071 1,081 350 361 372 284 259

2,496 2,536 2,475 2,380 1,599 1,710 1,702 1,255 1,295 1,380 987 934

371 371 338 348 354 367 366 159 161 162 357 355

544 594 600 624 561 582 590 571 592 615 490 504

5 5 5 6 1 2 2 52 51 50 2 2

17 51 24 25 70 71 72 163 169 178 118 114

1,138 1,248 1,225 1,185 2,904 2,948 3,121 3,019 1,849 1,851 1,594 1,580

99,705 94,431 89,156 83,881 78,606 75,849 73,244 68,708 68,061 63,476 60,596 56,579

22,419 22,904 23,389 23,874 24,358 23,668 23,689 23,316 24,178 24,677 22,662 21,999

6,934 7,082 9,656 7,298 15,016 7,316 7,184 11,410 12,964 8,676 18,493 17,364

140,895 135,902 133,558 126,778 128,859 117,911 115,380 114,541 114,465 106,263 111,057 105,078
2004 2005 2006 2007 2008

647 643 661 680 699

1,190 1,152 1,173 1,195 1,216

3,404 3,331 3,343 3,356 3,369

233 208 227 246 265

882 829 869 908 947

353 351 352 353 355

519 534 522 511 500

2 2 2 2 2

111 107 110 113 115

1,567 1,554 1,564 1,574 1,584

52,562 48,544 45,318 42,092 38,866

21,336 20,672 19,793 18,915 18,036

16,235 15,106 13,981 12,856 11,731

99,041 93,034 87,915 82,801 77,685
Ammonia (NH3)

National Emission Trends (thousand short tons) 

Source Category 1990 1991 1992 1993 1994 1995

FUEL COMB. ELEC. UTIL. 0 0 0 0 0 0

FUEL COMB. INDUSTRIAL 17 17 17 18 18 18

FUEL COMB. OTHER 8 8 8 8 8 8

CHEMICAL & ALLIED PRODUCT MFG 183 183 183 183 183 183

METALS PROCESSING 6 6 6 6 6 6

PETROLEUM & RELATED INDUSTRIES 43 43 43 43 43 43

OTHER INDUSTRIAL PROCESSES 38 38 39 39 40 40

SOLVENT UTILIZATION NA NA NA NA NA NA 

STORAGE & TRANSPORT 0 0 0 0 0 0

WASTE DISPOSAL & RECYCLING 82 86 89 93 93 93

HIGHWAY VEHICLES 155 169 182 195 209 222

OFF-HIGHWAY 31 35 35 36 36 37

MISCELLANEOUS 3,757 3,799 3,841 3,897 3,953 4,009

TOTAL 4,320 4,384 4,443 4,518 4,589 4,659
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006

6 6 8 11 11 11 29 28 27 27 29

34 33 33 31 31 31 17 17 17 17 16

7 7 6 8 8 8 18 18 17 17 17

123 125 130 25 26 27 23 23 23 23 23

5 5 5 2 2 2 3 3 3 3 3

16 17 17 9 10 10 3 3 3 3 3

43 45 45 48 50 52 177 177 177 177 168

0 0 0 0 0 0 0 0 0 0 0

1 1 1 5 5 5 1 1 1 1 1

84 84 86 82 83 85 26 26 26 26 26

236 265 256 267 275 278 294 298 302 307 306

34 34 35 3 3 3 3 3 3 3 3

4,138 4,195 4,318 4,366 4,403 3,177 3,539 3,539 3,539 3,539 3,540

4,727 4,817 4,940 4,857 4,907 3,689 4,133 4,136 4,138 4,143 4,135
2007

32

16

17

23

3

3

159

1

26

307

3

3,541

4,131
Nitrogen Oxides (NOx)

National Emission Trends (thousand short tons) 

Source Category 1970 1975 1980 1985 1990 1991

FUEL COMB. ELEC. UTIL. 4,900 5,694 7,024 6,127 6,663 6,519

FUEL COMB. INDUSTRIAL 4,325 4,007 3,555 3,209 3,035 2,979

FUEL COMB. OTHER 836 785 741 712 1,196 1,281

CHEMICAL & ALLIED PRODUCT MFG 271 221 213 262 168 165

METALS PROCESSING 77 73 65 87 97 76

PETROLEUM & RELATED INDUSTRIES 240 63 72 124 153 121

OTHER INDUSTRIAL PROCESSES 187 182 205 327 378 352

SOLVENT UTILIZATION 0 0 0 2 1 2

STORAGE & TRANSPORT 0 0 0 2 3 6

WASTE DISPOSAL & RECYCLING 440 159 111 87 91 95

HIGHWAY VEHICLES 12,624 12,061 11,493 10,932 9,592 9,449

OFF-HIGHWAY 2,652 2,968 3,353 3,576 3,781 3,849

MISCELLANEOUS 330 165 248 310 369 286

TOTAL 26,882 26,378 27,080 25,757 25,527 25,180
1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

6,504 6,651 6,565 6,384 6,164 6,276 6,232 5,721 5,330 4,917 4,709 4,404

3,071 3,151 3,147 3,144 3,151 3,101 3,050 2,709 2,723 2,757 2,041 1,967

1,353 1,308 1,303 1,298 1,197 1,177 1,101 768 766 779 738 735

163 155 160 158 125 127 129 102 105 107 70 67

81 83 91 98 83 89 89 86 89 94 69 68

148 123 117 110 139 143 143 120 122 124 354 354

361 370 389 399 433 460 467 451 479 504 429 447

3 3 3 3 2 3 3 4 4 4 7 6

5 5 5 6 15 16 16 14 15 16 19 18

96 123 114 99 153 157 163 162 129 130 111 122

9,306 9,162 9,019 8,876 8,733 8,792 8,619 8,371 8,394 7,774 7,870 7,411

3,915 3,981 4,047 4,113 4,179 4,178 4,156 4,084 4,167 4,156 4,507 4,634

255 241 390 267 412 187 179 251 276 184 211 231

25,261 25,356 25,350 24,955 24,786 24,706 24,347 22,843 22,599 21,546 21,135 20,464
2004 2005 2006 2007 2008

4,098 3,792 3,446 3,320 3,006

1,894 1,820 1,826 1,832 1,838

733 730 729 728 727

64 61 63 65 67

67 66 67 68 68

354 354 352 351 350

464 482 461 439 418

5 4 5 6 6

17 16 17 18 18

134 146 137 129 120

6,951 6,492 6,063 5,635 5,206

4,761 4,888 4,677 4,466 4,255

251 271 267 264 260

19,793 19,122 18,110 17,321 16,339
Particulate Matter 10 Micrometers in Diameter and Smaller (PM10)

National Emission Trends, without Condensables (thousands short tons)

Source Category 1970 1975 1980

FUEL COMB. ELEC. UTIL. 1,775 1,191 879

FUEL COMB. INDUSTRIAL 641 564 679

FUEL COMB. OTHER 455 492 887

CHEMICAL & ALLIED PRODUCT MFG 235 127 148

METALS PROCESSING 1,316 825 622

PETROLEUM & RELATED INDUSTRIES 286 179 138

OTHER INDUSTRIAL PROCESSES 5,832 2,572 1,846

SOLVENT UTILIZATION NA NA NA 

STORAGE & TRANSPORT NA NA NA 

WASTE DISPOSAL & RECYCLING 999 371 273

HIGHWAY VEHICLES 480 456 432

OFF-HIGHWAY 164 209 257

MISCELLANEOUS 839 569 852

TOTAL 13,022 7,555 7,013
1985 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

280 295 257 257 279 273 268 289 295 229 227 225

247 270 233 243 257 270 302 238 232 229 209 211

1,009 631 657 683 588 570 610 380 381 378 417 457

58 77 68 71 66 76 67 63 64 65 36 37

220 214 251 250 181 184 212 144 151 150 65 67

63 55 43 43 38 38 40 29 30 30 29 29

611 583 520 506 501 495 511 325 336 338 282 293

2 4 5 5 6 6 6 6 6 6 17 17

107 102 101 117 114 106 109 81 83 84 69 71

278 271 276 278 334 313 287 454 468 488 467 361

408 387 370 354 337 321 304 287 274 256 241 230

304 328 331 333 335 337 339 341 337 332 336 322

37,736 24,536 24,233 23,958 24,328 25,619 22,765 20,220 20,253 20,307 20,179 20,642

41,323 27,753 27,345 27,098 27,364 28,608 25,820 22,857 22,910 22,892 22,574 22,962
2001 2002 2003 2004 2005 2006 2007 2008

258 219 218 217 215 184 153 122

220 251 238 225 212 206 199 192

459 69 69 68 67 67 68 68

38 36 32 27 22 23 24 25

71 64 51 38 25 23 21 20

30 22 19 15 12 10 9 8

305 867 848 829 810 796 782 768

18 8 7 5 4 4 4 4

74 51 45 40 34 34 34 34

362 235 233 232 231 231 231 231

212 203 200 196 193 186 178 171

317 311 322 334 345 331 318 304

20,573 16,095 16,095 16,095 16,095 14,054 12,013 9,972

22,937 18,431 18,377 18,321 18,265 16,149 14,034 11,919
Particulate Matter 10 Micrometers in Diameter and Smaller (PM10)

National Emission Trends, with Condensables from 1999 forward (thousands short tons)

Source Category 1970

FUEL COMB. ELEC. UTIL. 1,775

FUEL COMB. INDUSTRIAL 641

FUEL COMB. OTHER 455

CHEMICAL & ALLIED PRODUCT MFG 235

METALS PROCESSING 1,316

PETROLEUM & RELATED INDUSTRIES 286

OTHER INDUSTRIAL PROCESSES 5,832

SOLVENT UTILIZATION NA 

STORAGE & TRANSPORT NA 

WASTE DISPOSAL & RECYCLING 999

HIGHWAY VEHICLES 480

OFF-HIGHWAY 164

MISCELLANEOUS 839

TOTAL 13,022
1975 1980 1985 1990 1991 1992 1993 1994 1995 1996 1997 1998

1,191 879 280 295 257 257 279 273 268 289 295 229

564 679 247 270 233 243 257 270 302 238 232 229

492 887 1,009 631 657 683 588 570 610 380 381 378

127 148 58 77 68 71 66 76 67 63 64 65

825 622 220 214 251 250 181 184 212 144 151 150

179 138 63 55 43 43 38 38 40 29 30 30

2,572 1,846 611 583 520 506 501 495 511 325 336 338

NA NA 2 4 5 5 6 6 6 6 6 6

NA NA 107 102 101 117 114 106 109 81 83 84

371 273 278 271 276 278 334 313 287 454 468 488

456 432 408 387 370 354 337 321 304 287 274 256

209 257 304 328 331 333 335 337 339 341 337 332

569 852 37,736 24,536 24,233 23,958 24,328 25,619 22,765 20,220 20,253 20,307

7,555 7,013 41,323 27,753 27,345 27,098 27,364 28,608 25,820 22,857 22,910 22,892
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

723 687 696 620 622 625 627 596 565 534

317 320 330 339 343 346 350 343 337 330

421 465 467 491 482 473 464 465 465 466

54 55 57 40 38 37 36 37 38 39

136 140 148 81 82 83 83 81 79 78

38 38 39 25 26 27 28 27 25 24

365 378 394 976 987 998 1,009 995 981 967

17 17 18 8 8 8 8 8 8 8

83 84 88 60 59 58 58 58 57 57

468 362 363 289 289 289 289 289 289 288

241 230 212 203 200 196 193 186 178 171

336 322 317 311 322 334 345 331 318 304

20,186 20,650 20,581 17,883 17,809 17,736 17,662 15,622 13,581 11,540

23,385 23,748 23,710 21,326 21,267 21,210 21,152 19,038 16,921 14,806
Particulate Matter 2.5 Micrometers in Diameter and Smaller (PM2.5)

National Emission Trends, without Condensables (thousands short tons)

Source Category 1990 1991 1992

FUEL COMB. ELEC. UTIL. 121 105 106

FUEL COMB. INDUSTRIAL 177 151 159

FUEL COMB. OTHER 611 638 662

CHEMICAL & ALLIED PRODUCT MFG 47 43 45

METALS PROCESSING 157 197 198

PETROLEUM & RELATED INDUSTRIES 27 24 24

OTHER INDUSTRIAL PROCESSES 284 264 259

SOLVENT UTILIZATION 4 4 5

STORAGE & TRANSPORT 42 42 50

WASTE DISPOSAL & RECYCLING 234 238 239

HIGHWAY VEHICLES 323 308 292

OFF-HIGHWAY 300 303 305

MISCELLANEOUS 5,233 5,003 4,854

TOTAL 7,560 7,320 7,198
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

112 108 107 157 161 130 125 126 145 117 116 116

172 183 203 152 148 147 149 151 157 117 109 102

568 550 589 356 356 354 396 439 441 54 53 53

41 49 42 39 39 40 27 28 29 26 23 20

125 125 134 101 106 105 44 46 48 40 32 24

22 22 22 17 17 17 18 18 18 16 13 10

260 256 256 180 186 189 162 168 175 256 247 237

6 6 5 5 5 5 17 17 17 5 4 3

46 43 42 30 31 31 27 28 29 18 16 15

288 271 247 427 439 459 439 333 333 219 218 216

276 261 245 229 216 199 184 173 157 148 144 140

307 309 311 313 309 304 307 295 290 291 302 313

4,926 5,359 4,726 4,721 4,244 4,280 4,504 4,681 4,382 1,795 1,795 1,795

7,149 7,542 6,929 6,727 6,257 6,260 6,399 6,503 6,221 3,102 3,072 3,044
2005 2006 2007 2008

115 80 45 10

94 88 82 75

52 52 52 51

17 17 17 17

16 13 10 8

7 6 5 3

227 216 206 195

2 2 2 2

13 12 11 10

215 216 216 217

136 128 119 110

324 310 297 283

1,795 1,686 1,577 1,468

3,013 2,826 2,639 2,449
Particulate Matter 2.5 Micrometers in Diameter and Smaller (PM2.5)

National Emission Trends, with Condensable from 1999 forward (thousands short tons)

Source Category 1990

FUEL COMB. ELEC. UTIL. 121

FUEL COMB. INDUSTRIAL 177

FUEL COMB. OTHER 611

CHEMICAL & ALLIED PRODUCT MFG 47

METALS PROCESSING 157

PETROLEUM & RELATED INDUSTRIES 27

OTHER INDUSTRIAL PROCESSES 284

SOLVENT UTILIZATION 4

STORAGE & TRANSPORT 42

WASTE DISPOSAL & RECYCLING 234

HIGHWAY VEHICLES 323

OFF-HIGHWAY 300

MISCELLANEOUS 5,233

TOTAL 7,560
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

105 106 112 108 107 157 161 130 621 587 584 506

151 159 172 183 203 152 148 147 258 260 267 178

638 662 568 550 589 356 356 354 400 447 449 445

43 45 41 49 42 39 39 40 45 46 47 30

197 198 125 125 134 101 106 105 115 118 125 54

24 24 22 22 22 17 17 17 27 27 28 18

264 259 260 256 256 180 186 189 245 254 264 354

4 5 6 6 5 5 5 5 17 17 17 7

42 50 46 43 42 30 31 31 41 42 44 23

238 239 288 271 247 427 439 459 440 333 334 268

308 292 276 261 245 229 216 199 184 173 157 148

303 305 307 309 311 313 309 304 307 295 290 291

5,003 4,854 4,926 5,359 4,726 4,721 4,244 4,280 4,511 4,688 4,390 3,256

7,320 7,198 7,149 7,542 6,929 6,727 6,257 6,260 7,211 7,287 6,996 5,578
2003 2004 2005 2006 2007 2008

509 513 516 480 445 410

183 189 194 188 182 175

437 429 422 421 421 421

30 29 29 29 29 29

56 58 60 58 55 52

19 20 21 20 18 17

365 376 387 377 366 355 7 7 7 7 7 7

24 24 25 24 23 22

267 267 266 266 267 267

144 140 136 128 119 110

302 313 324 310 297 283

3,194 3,131 3,069 2,960 2,851 2,742

5,537 5,496 5,456 5,268 5,080 4,890
Sulfur Dioxide (SO2)

National Emission Trends (thousands short tons)

Source Category 1970 1975 1980 1985 1990 1991

FUEL COMB. ELEC. UTIL. 17,398 18,268 17,469 16,272 15,909 15,784

FUEL COMB. INDUSTRIAL 4,568 3,310 2,951 3,169 3,550 3,256

FUEL COMB. OTHER 1,490 1,082 971 579 831 755

CHEMICAL & ALLIED PRODUCT MFG 591 367 280 456 297 280

METALS PROCESSING 4,775 2,849 1,842 1,042 726 612

PETROLEUM & RELATED INDUSTRIES 881 727 734 505 430 378

OTHER INDUSTRIAL PROCESSES 846 740 918 425 399 396

SOLVENT UTILIZATION NA NA NA 1 0 0

STORAGE & TRANSPORT NA NA NA 4 7 10

WASTE DISPOSAL & RECYCLING 8 46 33 34 42 44

HIGHWAY VEHICLES 273 334 394 455 503 469

OFF-HIGHWAY 278 301 323 354 371 379

MISCELLANEOUS 110 20 11 11 12 11

TOTAL 31,218 28,044 25,926 23,307 23,077 22,374
1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

15,416 15,189 14,889 12,080 12,767 13,195 13,416 12,583 11,396 10,850 10,436 10,425

3,292 3,284 3,218 3,357 2,849 2,805 2,740 2,135 2,139 2,243 1,786 1,769

784 772 780 793 636 648 586 620 628 642 579 580

278 269 275 286 255 259 261 325 338 342 259 257

615 603 562 530 389 407 405 304 313 332 213 200

416 383 379 369 335 344 342 312 316 319 257 237

396 392 398 403 386 409 415 382 410 429 325 337

1 1 1 1 1 1 1 1 1 1 0 0

9 5 2 2 5 5 5 6 6 7 5 4

44 71 59 47 32 33 34 34 34 35 26 27

436 402 369 335 302 304 300 300 260 248 245 212

385 392 399 406 413 422 432 475 437 440 508 617

10 10 15 10 15 7 6 67 70 44 135 132

22,082 21,773 21,346 18,619 18,385 18,839 18,943 17,544 16,348 15,932 14,774 14,797
2004 2005 2006 2007 2008

10,415 10,404 9,404 8,941 7,552

1,752 1,735 1,713 1,692 1,670

581 582 580 579 578

254 251 253 254 255

187 175 184 194 203

218 199 201 203 206

349 361 350 340 329

0 0 0 0 0

3 3 3 4 4

28 28 28 28 27

179 146 119 91 64

725 834 708 582 456

129 126 112 98 85

14,820 14,844 13,655 13,006 11,429
Volatile Organic Compounds (VOC)

National Emission Trends (thousands short tons)

Source Category 1970 1975 1980 1985 1990 1991

FUEL COMB. ELEC. UTIL. 30 40 45 32 47 44

FUEL COMB. INDUSTRIAL 150 150 157 134 182 196

FUEL COMB. OTHER 541 470 848 1,403 776 835

CHEMICAL & ALLIED PRODUCT MFG 1,341 1,351 1,595 881 634 710

METALS PROCESSING 394 336 273 76 122 123

PETROLEUM & RELATED INDUSTRIES 1,194 1,342 1,440 703 611 640

OTHER INDUSTRIAL PROCESSES 270 235 237 390 401 391

SOLVENT UTILIZATION 7,174 5,651 6,584 5,699 5,750 5,782

STORAGE & TRANSPORT 1,954 2,181 1,975 1,747 1,490 1,532

WASTE DISPOSAL & RECYCLING 1,984 984 758 979 986 999

HIGHWAY VEHICLES 16,910 15,392 13,869 12,354 9,388 8,860

OFF-HIGHWAY 1,616 1,917 2,192 2,439 2,662 2,709

MISCELLANEOUS 1,101 716 1,134 566 1,059 756

TOTAL 34,659 30,765 31,107 27,403 24,108 23,577
1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

44 45 45 44 50 52 56 54 62 61 49 49

187 186 196 206 179 175 174 172 173 176 152 146

884 762 748 823 893 893 889 919 949 950 1,523 1,211

715 701 691 660 388 388 394 251 254 262 249 245

124 124 126 125 73 78 78 66 67 71 46 47

632 649 647 642 477 487 485 457 428 441 601 588

414 442 438 450 435 438 443 438 454 420 442 447

5,901 6,016 6,162 6,183 5,477 5,621 5,149 5,036 4,831 5,012 4,278 4,267

1,583 1,600 1,629 1,652 1,294 1,328 1,327 1,237 1,176 1,192 1,484 1,470

1,010 1,046 1,046 1,067 509 518 535 487 415 420 395 394

8,332 7,804 7,277 6,749 6,221 5,985 5,859 5,681 5,325 4,952 4,917 4,649

2,754 2,799 2,845 2,890 2,935 2,752 2,673 2,682 2,644 2,622 3,057 2,994

486 556 720 551 1,941 816 718 791 733 533 3,970 3,970

23,066 22,730 22,570 22,042 20,872 19,531 18,780 18,271 17,511 17,112 21,163 20,477
2004 2005 2006 2007 2008

49 48 49 50 50

139 133 132 131 130

900 589 816 1,042 1,269

240 235 233 231 228

48 49 48 47 46

575 562 562 561 561

452 457 439 422 404

4,256 4,245 4,239 4,232 4,226

1,456 1,442 1,396 1,349 1,303

393 392 386 380 374

4,381 4,112 3,881 3,650 3,418

2,930 2,866 2,773 2,679 2,586

3,970 3,291 2,638 1,985 1,332

19,789 18,421 17,592 16,759 15,927