Bland Alman Plot2
   Last Monday took place the 17th meeting of Working Group 41 (WG41) that is dealing on the new standard for Instrumental Odour Monitoring Systems (IOMS). This meeting was focusing on the statistics behind the Quality Assurance Level 1 (QAL1) of IOMSs. There are some aspects that make IOMS special as compared to other Automatic Measuring Systems (AMS) and one of these aspects is the cost of comparing the electronic signal of the IOMS with that of the reference method EN 13725.

   One of the key issues addressed many times during the WG41 meetings is that of the number of samples that should be taken in order to make QAL1 checks viable for IOMS manufacturers. Dynamic Olfactometry comes at a cost and odour is not a substance, it is a class. The question is: how many samples should be taken in order to have a representative picture of the IOMS performance?

   P48I3 Fugitive emissions of biogas in the Urban Solid Waste Treatment Plants are an important source of odors. These emissions that occur, for example, in the landfills cells, even when these are degassed with drainage wells connected for the extraction, transport and storage of the gas for its energetic use, or for torch burning, they are very difficult to detect and require processes that require a lot of time and high execution costs.

   The optical visualization of biogas using an infrared gas analyzer (Smart inspec-tion) allows obtaining excellent results by implementing leak identification and reduction programs with an unbeatable cost-effectiveness ratio.

A. Torres, J.V. Martínez, M.A. Cid, R. Cerdá

Labaqua S.A. Alicante (Spain)

 

WG41 virtual meeting april2020The 16th meeting of the Working Group (WG) 41 of the European Standardization Committee took place at the end of April A couple of intensive days with online meetings due to the Covid-19 measures taken by most European countries at that stage. A nice session of statistics and mathematics took place during those days, with the Chebyshev's inequality and the Bland–Altman plot as stars of these sessions. 

16 experts from Belgium, Italy, Germany, Netherlands, Spain and UK got together to bring ideas to the important issue of dealing with the mathematics involved in comparing the results of olfactometric samples with those of an IOMS. A calculation of a correlation coefficient has several limitations and that is why more advanced approaches were discussed during these two days of intensive work.

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