Several aspects should be taken into account in order to investigate the relevance of non-exhaust traffic related particle emissions, and particularly those generated as a result of brake wear, in human health. For some aspects already available literature data is sufficient to draw safe conclusions, since there is a general consensus among the scientific community, while on the other hand, there are others for which the current knowledge is not enough to reach sound conclusions. The use of different measurement techniques and sampling procedures is one of the most important reasons why not consistent - or even sometimes contrasting - results have been reported in the literature. The Particle Measurement Program Informal Working Group (PMP-IWG) comprises experts from the field of exhaust emissions, as well as experts on techniques and sampling systems to characterize particles emitted by engines. Lately, also brake and tyre wear emission experts have been following the activities of the PMP group. Having recognized the lack of a harmonized method for measuring brake wear particles as an important reason for not consistent reported results, the PMP group aims in setting the framework for the development of such a harmonized method in order to improve the comparability of the results of future studies and assess real world brake wear emission factors. For that reason the PMP group has identified and focused its work on 4 working items: The investigation of typical driving patterns and in particular of typical accelerations/decelerations, with the target of providing guidance for the harmonization of future studies by reaching a shared definition of typical driving conditions as well as of severe, extreme or infrequent conditions, the compilation and monitoring of the on-going research projects on non-exhaust traffic related particle emissions, with the target of promoting the exchange of information among all involved parties and avoiding overlapping of the activities, the networking and exchange of information with experts in the field of non-exhaust traffic related particle emissions, and finally the development of a set of recommended measurement techniques and sampling procedures, which will be based upon the research needs and objectives and will serve as a guideline for future studies.
Theodoros Grigoratos, Giorgio Martini - European Commission, Joint Research Centre (JRC)