Analytical approaches for arsenic determination in air: A critical review. 
This review describes the different steps involved in the determination of arsenic in air, considering the particulate matter (PM) and the gaseous phase.  The review focuses on sampling, sample preparation and instrumental analytical techniques for both total arsenic determination and speciation analysis.  The origin, concentration and legislation concerning arsenic in ambient air are also considered.  The review intends to describe the procedures for sample collection of total suspended particles (TSP) or particles with a certain diameter expressed in microns (e.g. PM10 and PM2.5), or the collection of the gaseous phase containing gaseous arsenic species.  Sample digestion of the collecting media for PM is described, indicating proposed and established procedures that use acids or mixtures of acids aided with different heating procedures.  The detection techniques are summarized and compared (ICP-MS, ICP-OES and ET-AAS), as well those techniques capable of direct analysis of the solid sample (PIXE, INAA and XRF).  The studies about speciation in PM are also discussed, considering the initial works that employed a cold trap in combination with atomic spectroscopy detectors, or the more recent studies based on chromatography (GC or HPLC) combined with atomic or mass detectors (AFS, ICP-MS and MS).  Further trends and challenges about determination of As in air are also addressed.