THE NORTHERN Health Authority recommended the installation of scrubbers to minimize the emission of sulphur dioxide into the air as part of Rio Tinto Alcan's Kitimat smelter modernization project now underway.
The recommendation, contained in a review by the authority of Rio Tinto's plans and sent to the company and to the environment ministry, is consistent with its approach to public health, says Dr. David Bowering, the authority's senior health officer in the region.
“We want people to minimize the risk to air quality and to the air shed as much as they can,” he said last week.
“And that would be to use the best possible technology and that would be scrubbers,” he added.
Scrubbing, or flue gas desulphurization, refers to procedures that remove sulphur dioxide from gas using chemical and mechanical processes, usually transferring it to water or solid waste.
Sulphur dioxide is a byproduct of aluminum smelting and because the new smelter will produce more aluminum than the current one, the amount of sulphur dioxide produced will increase.
The environment ministry has issued a permit allowing Rio Tinto to emit more sulphur dioxide into the air than is now the case.
The health authority review also recommended the permit contain a “trigger” to cut emissions through a reduction in production or by other measures should the technical assessment of the emissions plan be found to have underestimated the risk to the population.
Bowering noted that the health authority's review and recommendations were submissions made to the company and to the environment ministry and were not necessarily incorporated into the permit issued to the company.
He also said it was important to place the increased sulphur dioxide emissions within the context of other potential industrial development in the region.
“You just can't look at this in isolation,” said Bowering of the cumulative impact to the airshed of Rio Tinto Alcan's new smelter and of planned liquefied natural gas plants to be based in Kitimat.