This paper describes the results of an intercomparison exercise referring to the measurement of atmospheric pollutants emitted by cement plants. The research was conducted in 2008 in Catalonia, Spain. Thirteen Spanish companies accredited to make pollutant measurements and with suitably approved equipment and trained staff participated in the research. The aim of the research was to evaluate the technical competence of the accredited companies in conducting tests in situ. The results obtained from the application of the methodology described in international standards--on the basis of conventional statistical analyses--were compared with those obtained using functional data analysis. On comparing the two methods, it was concluded that the functional method, although more complex, has advantages over the conventional statistical method. This is because the functional approach compares curves rather than mean values. Furthermore, it does not presuppose a normal distribution of the data.