Results of the first EC/OC comparison exercise for EU national air quality reference laboratories (AQUILA)

The JRC's European Reference Laboratory for Air Pollution (ERLAP) has organized in 2009 an inter-laboratory comparison for the measurement of elemental carbon (EC) and organic carbon (OC) in particulate matter sampled on filters. The objectives of this comparison have been to evaluate the performances of participants but also to study the effects of the use of different thermal analysis protocols currently used for analysis. It has been shown that all participants using laboratory analyzers are able to meet a 25% expanded uncertainty as a "fitness-for-purpose" criterion for total carbon (TC, as the sum of OC and EC) and OC. For EC this criterion is only met when results are evaluated by specific protocols (NIOSH or EUSAAR2) separately. Ratios of repeatability and reproducibility standard deviations indicate that the thermal-optical method used is quite robust.