141. The operator of an aluminum smelter must measure the contaminants referred to in sections 132 to 135 that are emitted into the atmosphere for all potlines.
In the case of potline scrubbers, the operator must measure the contaminants(1) at least once every 2 years when the aluminum smelter has at least 5 scrubbers; and
(2) at least once every 3 years when the aluminum smelter has 5 scrubbers or more.
If potlines are connected to less than 5 scrubbers each, the operator must measure the emissions of at least 1 potline per year.
In the case of potline roof vents, the operator must measure the contaminants every 4 weeks.
This section applies to existing aluminum smelters as of 30 June 2013.