The URG 9000 Series Ambient Ion Monitor (AIM) is an advanced air sampling instrument that
simultaneously measures both fine particle composition (PM2.5) and precursor gases. The AIM
enables the analysis of not only the atmospheric chemistry leading to the formation of PM2.5, but
also physical transformation and subsequent particle/gas partitioning of its constituents. AIM
samplers provide time-resolved direct measurements of anions (nitrate, sulfate, nitrite, phosphate
and chloride) and cation particulates (ammonium, sodium, calcium, potassium and magnesium) in
PM2.5. Furthermore, the AIM provides time resolved direct measurements of anion (hydrogen
chloride, nitric acid, nitrous acid and sulfur dioxide) and cation (ammonia) gases.
AIM samplers collect and prepare air samples. They are configured with one or two Dionex Ion
Chromatography (IC) systems, as shown in Figure 1. The ion chromatographs separate, identify
and quantify ionic pollutants such as ammonium, chloride, nitrate, nitrite and sulfate. These
systems include dual-piston pumps, manually or electrolytically generated eluents and electrolytic
suppression for ion chromatography. Table 1 describes individual parameters for the AIM samplers.