Analytical quantification of uncertainties and compiling of evidence bases The aim of this work package is to quantify the contribution of sampling configurations available for collecting HCl in accordance with EN 1911 and accredited analytical laboratories on uncertainty, and compile evidence bases with respect to EN 1911 and portable optical systems for BAT Conclusions industries. Task 2.1 will carry out work related to the absorbing solution used when carrying out EN 1911. Specifically, the impact of different glassware configuration readily available and collection parameters will be investigated. Also, the variance of EN 1911 due solely to accredited analytical laboratories that offer chloride quantification will be isolated. Task 2.2 will bring together and analyse work from Task 2.1 and all three tasks in WP1 to build a complete picture of the various uncertainty contributions to EN 1911 at low HCl emissions and to analyse results from the testing of the portable optical systems which may offer an improved long term replacement for EN 1911.