The above graph shows the combined results of average fluoride emissions for the stacks at the fume treatment centers and the roof vents at the potrooms. A standard of 0.95 kg F/t Al for annual fluoride emissions was established in 2011 for the three plants using the prebake technology. The Deschambault Smelter has been subject to this standard since 2007.
In 2013, total Fluoride emissions were 8% lower at the Bécancour Smelter (0.71 t F/t Al in 2013 compared to 0.78 t F/t Al in 2012) as a result of the action plan implemented in July 2012, which integrated employee training with investment in new pot hoods. Fluoride emissions were slightly higher than in 2012 at the Baie-Comeau Smelter due to issues affecting gas capture, as well as at the Deschambault Smelter, because of carbon dust in the electrolysis process.
In addition, fluoride emissions from the Söderberg plant in Baie-Comeau had declined significantly during the final months of operation, following implementation of process improvements (1.66 t F/t Al in 2013 compared to 1.94 t F/t Al in 2012).