This document specifies a method for the determination of particulate lead (Pb), cadmium (Cd), arsenic (As) and nickel (Ni) in ambient air that can be used in the framework of the European Council Directive on Ambient Air Quality Assessment and Management [1] and the 1 st [2] and 4 th [3] Daughter Directives. Performance requirements with which the method has to comply are specified in this document. The performance characteristics of the method were determined in comparative field validation tests carried out at four European locations (see [4]). This document specifies a method for sampling of Pb, Cd, As and Ni as part of the PM10 aerosol, microwave digestion of the samples and analysis by graphite furnace atomic absorption spectrometry or by inductively coupled plasma (quadrupole) mass spectrometry. This document is applicable for the measurement of Pb, Cd, As and Ni as part of the PM10 aerosol fraction in the concentration ranges listed in Table 1. Table 1 - Working ranges of the method From ng/m3 To ng/m3 Pb 14000 Cd 0,1 50 As 0,5 350 Ni 2100 The actual lower limits of the working ranges depend upon the variability of the laboratory filter blank (5.3.1). The lower limits of the working ranges given in Table 1 are expected values based upon performance achieved in the field validation tests. Similarly the upper limits of the working ranges have been set arbitrarily based upon the maximum daily values measured during the field validation tests. The method can be applied to higher concentrations provided the PM10 collection characteristics of the sampler are not compromised.