| SO2, tonnes |
Refining | Flaring | Total |
| 1990 | 3335 | 945 | 4280 |
| 1991 | 2713 | 929 | 3642 |
| 1992 | 3147 | 938 | 4085 |
| 1993 | 2526 | 1193 | 3719 |
| 1994 | 4266 | 523 | 4789 |
| 1995 | 3022 | 205 | 3227 |
| 1996 | 2614 | 221 | 2835 |
| 1997 | 1982 | 141 | 2123 |
| 1998 | 1441 | 73 | 1514 |
| 1999 | 1359 | 55 | 1414 |
| 2000 | 981 | 55 | 1036 |
| 2001 | 672 | 50 | 722 |
| 2002 | 332 | 71 | 403 |
| 2003 | 246 | 99 | 345 |
| 2004 | 119 | 57 | 176 |
| 2005 | 255 | 299 | 554 |
| 2006 | 679 | 260 | 938 |
| 2007 | 610 | 528 | 1137 |
| 2008 | 794 | 382 | 1175 |
| 2009 | 375 | 454 | 829 |