Development of a High Volume Cascade Impactor for Toxicological and Chemical Characterization Studies

Abstract

This paper presents the design and development of a compact high volume cascade impactor (HVCI).The HVCI operates at a ow rate of 900 l/min and consists of 4 impaction stages equipped with circular slit-shaped acceleration nozzles and a backup lter. The backup lter is placed downstream of the fourth stage and is used to collect the ultra ne particles (d p < 0.1 ¹m). The major feature of this novel sampler is its ability to collect relatively large amounts of particles (mg-g levels) onto relatively small polyurethane foam substrates without using adhesives. As previously reported, the capacity of the impaction substrate is 2.15 g of collected particles per cm 2 of foam. Although the impaction substrates are not coated with adhesives such as grease or mineral oil, particle bounce and re-entrainment losses were found not to be signi cant. Particles can be easily recovered from the foam substrates using aqueous extraction. The impactor was calibrated using polydisperse particles. The 50% cutpoints of the 4 stages were 9.90, 2.46, 1.0, and 0.1 ¹m, respectively. Interstage losses of ultra ne and ne particles were <10% and for coarse particles were <20%. The pressure drop across the 4 stages and the backup lter were 0.25, 0.75, 1.25, 19.9, and 3.3 kPa, respectively.

A Novel Method Using Polyurethane Foam (PUF) Substrates to Determine Trace Element Concentrations in Size-Segregated Atmospheric Particulate Matter on Short Time Scales

“…PUF weights range from 0.5 grams for the sub-micron stages to ∼2 grams for the PM10 stage substrate. The accelerator slits immediately upstream of the PUF in each stage produce narrow (several mm width) PM deposits on the PUF (Demokritou et al 2002). Three identically sized slits at each stage deposit PM on ∼85% of the PUF substrate.…”

“…To obtain high time resolution size-segregated PM samples, a Rupprecht and Patashnick, ChemVol Model 2400 High Volume Cascade Impactor (Demokritou et al 2002) with six sampling stages was used. The sampler was operated at the manufacturer recommended flow rate of 760 liters per minute (lpm) and based on unpublished data from the manufacturer for the stages used, particles were collected in the following diameters size ranges, <0.1, 0.1-0.5, 0.5-1.0, 1.0-2.5, 2.5-10, >10 μm.…”

Release of Bet v 1 from birch pollen from 5 European countries. Results from the HIALINE study

“…In brief: 800 l min À1 ambient air was sampled on polyurethane foam with a high-volume Chemvol Ò cascade impactor equipped with size class stages PM > 10 mm and 10 mm > PM > 2.5 mm (Butraco Inc., Son, Netherlands) (Demokritou et al, 2002). In Munich, the stage 2.5 mm > PM > 0.12 mm was also sampled.…”

Development and Evaluation of a High Loading PM2.5Speciation Sampler

“…For this substrate, without using adhesives such as grease or mineral oil, particle bounce and re-entrainment losses were found to be not significant. This PUF substrate was used in both a high volume cascade impactor (Demokritou et al 2002b) and a high volume low cutpoint impactor (Kavouras et al 2000) for physicochemical and toxicological characterization of atmospheric aerosols.…”