Continuous Emission Monitoring (CEM) is regulated in many regions of the world. It is the intend to reduce the emission of pollutants that contribute to poor air quality and lead to significant negative impacts on human health and the environment. For that purpose, in many regions world-wide reduction commitments have been agreed upon and been manifested in directives (e.g. National Emission Ceilings Directive 2016/2284/EU) and protocols.
Automated Measuring Systems (AMS) are used to quantify pollutants emitted to air. Various standards, issued by the ISO or CEN organization, describe performance criteria, that must be met by AMS in order to meet maximum permissible measurement uncertainties as mandated in corresponding regulations.
AMS installed in the field are connected to a Data acquisition and handling systems (DAHS). The DAHS, typically a computer-based system, acquires the measurements from the AMS. It then averages these values and compares them with the Emission Limit Values (ELV) set-out. Finally, an emissions report is then drawn up, on the basis of which operating permits are issued.
To date, there is no DAHS international standard available, that stipulates the conversion of data from an AMS to reported data, specifies performance and test criteria and mandates QA/QC for DAHS. That means pollutant concentrations calculated by DAHS are dependent on the algorithms installed. As a result, emissions reported are a question of the algorithm implemented and therefor data reported is not consistent. This contradicts the idea of reporting emissions uniformly and meet emission ceilings.
The coming European standard EN 17255 unifies calculations, specifies performance specifications, requires a certification and has QA/QC requirements to make sure, that DAHS deliver comparable emission concentrations and lead to comparable emission reports.