scope:

This Standard sets out a gravimetric procedure for the concurrent determination of the PM₁₀ and PM_2.5 fractions 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 than approximately 2.5 μm) and the coarse fraction (2.5 μm to 10 μm). 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.

NOTE: Sampling is normally of 24 h duration to average out diurnal variations. Provided that the mass of the filter is determined under carefully controlled laboratory conditions, mean concentrations of 5 μg/m³ (1.67 L/min sample flow rate) or 1 μg/m³ (15 L/min sample flow rate) and greater may be determined, based on a 24 h sampling period.