This document specifies a measurement method for the determination of particulate benzo[a]pyrene (BaP) in ambient air, which can be used in the framework of the Council Directive 96/62/EC  and the Directive 2004/107/EC .This document specifies performance characteristics and performance criteria for the measurement method when it is used as a reference method. The performance characteristics of the measurement method are based on a sampling period of 24 h.This document describes a measurement method which comprises sampling of BaP as part of the PM10 particles, sample extraction and analysis by high performance liquid chromatography (HPLC) with fluorescence detector (FLD) or by gas chromatography with mass spectrometric detection (GC/MS). The method is applicable for the measurement of BaP in the concentration range from approx. 0,04 ng/m 3 to approximately 20 ng/m 3 . The lower limit of the applicable range depends on the noise level of the detector and the variability of the laboratory filter blank. NOTE If the BaP concentration exceeds the calibration range the extract can be diluted.