The graph combines the average total fluoride stack emissions from gas treatment centers and potroom roof vents for each smelter. An annual emissions standard of 0.95 kg F/mt Al took effect in 2011. This requirement has been applied to the Deschambault Smelter since 2007.
In 2015, fluoride emissions from vents at the Baie-Comeau Smelter increased slightly, notably due to repair work on its scrubbers, sometimes requiring shutdowns.
At the Bécancour Smelter, fluoride emissions were slightly lower in 2015 due to sustained efforts to improve process stability. Emissions at the Deschambault Smelter, which is equipped with double-capture technology, are lower than at the other plants. Improvements in the control of carbon dust generation also contributed to reducing emissions in 2015.