|A blind comparison of sulfate analysis by accredited laboratories and its implications for the uncertainty requirements of the European Union’s Industrial Emissions Directive for monitoring sulfur dioxide emissions
|Ms Alice Hirons
Abstract Information :
A blind comparison of five laboratories was conducted to assess the analysis of sulfate collected from industrial stacks in accordance with the European Standard Reference Method (SRM) for sulfur dioxide (SO2) (EN 14791): the method produced under European Commission mandate to support the enforcement of the Industrial Emissions Directive (IED). This was not to proficiency test the laboratories, rather to an assessment of the control that the EN 14791 method provides across the community and therefore, the suitability of the method for increasingly stringent emission limits. Both “synthetic” (sodium sulfate in aqueous hydrogen peroxide [H2O2(aq)]) and “real” (extracted from a stack simulator) samples were prepared across 2–10 and 10–290 mg·m0−3 emission equivalent concentration ranges, respectively.
It was found that EN 14791 was capable of enforcing IED waste incinerator emission limits as only 3% of deviations exceeded the required uncertainty. But it was not found to be an “effective tool” for calibrating automated measuring systems (AMSs), as 38.5% of the deviations exceeded recommended uncertainties. More work is needed to determine the capability of the SRM, and alternative methods at lower emission levels in addition to work towards improving uncertainties.