In order to be in compliance with EU Air Quality Directive requirements, the reference methods given in the Directive 2008/50/EC [1] for the measurement of mass concentrations of particulate matter are not commonly used for operation in routine monitoring networks. These networks usually apply automated continuous measurement systems (AMS), such as those based on the use of oscillating microbalances, ß-ray attenuation, or in-situ optical methods. Such AMS are typically capable of producing 24-hour average measurement values over a measurement range up to 1 000 µg/m3 and 1-hour average measurement values up to 10 000 µg/m3, if applicable, where the volume of air is the volume at ambient conditions near the inlet at the time of sampling. The 1-hour average values may be used for: a) direct information of the public; b) aggregation to produce daily or yearly average concentration values for regulatory reporting purposes. Directive 2008/50/EC allows the use of such systems after demonstration of equivalence with the reference method, i.e. after demonstration that these systems meet the Data Quality Objectives for continuous measurements. Guidelines for the demonstration of equivalence are given in Reference [2]. This European Standard lays down the minimum performance requirements and test procedures for the type approval of appropriate AMS for particulate matter. This includes the evaluation of its equivalence with the reference method as laid down in Directive 2008/50/EC. Further, this European Standard describes minimum requirements for ongoing quality assurance – quality control (QA/QC) of AMS deployed in the field. These requirements are necessary to ensure that uncertainties of measured concentrations are kept within the required limits during extended periods of continuous monitoring in the field, and include procedures for maintenance, calibration and control checks. Additional procedures are described that determine whether an instrument’s equivalence to the reference method is maintained through possible pollution climate changes, over periods longer than five years. Lastly, this European Standard describes harmonized requirements and procedures for the treatment and validation of raw measurement data that are used for the assembly of daily or yearly average concentration values. Experience with existing methods for data treatment and validation – for similar AMS – has shown that the different ways of data treatment and validation applied may lead to significant differences in reported results for similar datasets [3]. When the European Standard is used for purposes other than measurements required by Directive 2008/50/EC, the range and uncertainty requirements may not apply. This European Standard contains information for different groups of users. Clauses 5 and 6 and Annex A contain general information about the principles of automated continuous measurement systems for particulate matter, and relevant equipment. Clause 7 and Annexes B and C are specifically directed towards test houses and laboratories that perform type-approval testing of automated continuous measurement systems for particulate matter. These clauses contain information about: c) type-approval test conditions, test procedures and test requirements; d) system performance requirements; e) evaluation of the type-approval test results; f) evaluation of the uncertainty of the measurement results of the automated continuous measurement systems for particulate matter based on the type-approval test results. Clauses 8 to 11 are aimed at monitoring networks performing the practical measurements of particulate matter in ambient air. These clauses contain information about: g) initial installation of the system in the monitoring network and acceptance testing; h) ongoing quality assurance/quality control; i) on-going verification of suitability; j) treatment, validation and reporting of measurement results.