Sets out a sampling procedure and a gravimetric method for the determination of suspended particulate matter in ambient air. The method provides a measure of the mean concentration of PM(sub)10(/sub) of two particle size fractions, viz. less than approximately 2.5 µm and particles in the 2.5 µm to 10 µm size range.

This Standard sets out a gravimetric procedure for the determination of the PM10 fraction of suspended particulate matter in ambient air collected in a dichotomous sampler. The method provides a measure of the mean concentration of PM10 over the sampling period of the two size fractions, viz the fine fraction (less thanapproximately 2.5 um) and the coarse fraction (2.5 um to 10 um). A procedure for assessing the performance of dichotomous samplers so that they comply with the sampling requirements of this method, is described in Appendix A.NOTES:1. Sampling is normally of 24 h duration to average out diurnal variations. Provided the mass of the filter is determined under carefully controlled laboratory conditions, concentrations of 1 ug/m3 and greater may be determined using a 24 h sampling period.2. It is possible that some particulate matter, depending upon its hygroscopicity, may alter slightly in mass from its initial as-sampled state because of the filter equilibration procedure referred to in Clause 7.1. Such slight and indeterminable changes, if they occur, are considered insignificant.