translate English to French: There have been substantial reductions in quantities of sulphur dioxide released from eastern Canadian smelters and refineries owing to a combination of equipment installation and changes in metallurgical processes since the 1980s.
GrÃ¢ce Ã l'installation d'un Ã©quipement appropriÃ© et Ã l'adoption de nouveaux procÃ©dÃ©s mÃ©tallurgiques, des baisses importantes ont Ã©tÃ© enregistrÃ©es, depuis les annÃ©es 1980, dans les Ã©missions de dioxyde de soufre provenant des fonderies et des affineries de l'est du Canada.