189. A zinc production plant must not emit into the atmosphere in the form of sulphur dioxide more than 4% of the total sulphur introduced monthly into the process or more than 0.2 g of mercury per ton of zinc produced.
A zinc production plant must not emit sulphur dioxide into the atmosphere in such manner that the average concentration of the contaminant measured in the atmosphere at each sampling station exceeds the limits set out in the third and fourth paragraphs of section 184.