EKONERG - Laboratory for proficiency testing is from 17.1.2018. accredited proficiency testing provider with expanded scope of accreditation. The scope of accreditation is covering also waste gas measuring as follows:
Concentration CO (0-1800 µmol/mol)
Concentration NO (0-900 µmol/mol)
Concentration SO2 (0-2000 µmol/mol)
Concentration CO2 (0-0,18 mol/mol)
Concentration O2 (0-0,21 mol/mol)
Accreditation certificate is available here...