Optimized Portable Cordless Vacuum Method for Sampling Dry, Hard Surfaces for Dusts

Abstract

Surface sampling in industrial/environmental hygiene is a growing field that needs validated standardized methods. There are few standard methods, one being the American Society for Testing and Materials (ASTM) method involving a portable, cordless air sampling pump. In the present work, the ASTM technique was modified to increase efficiency and versatility. A soil sample was first dried and sieved. Known weights of different sieved sizes (125 microns-180 microns, 90 microns-125 microns, and 63 microns-90 microns) were then sampled at an average flow rate of 4.0 +/- 0.2 L/min from a template of inner dimensions 10 cm by 10 cm on two different surfaces (rough and smooth). Five consecutive sampling passes were performed. For the smooth surface, the first pass efficiency for the largest particles were 45% +/- 45% (CV = 100%), and 75% +/- 20% (CV = 27%) for the smallest particles. After three passes, the efficiency independent of particle size exceeded 83 percent with a CV better than 11 percent. After five passes, the efficiency exceeded at least 85 percent with about the same precision as for three passes. The rough surface allowed higher efficiencies for the first two sampling passes. Three to five passes are recommended to achieve acceptable efficiencies for the surface loose dust/soil range 100 micrograms/cm2 to 1,500 micrograms/cm2.

Effect of Dust on the Viability of Vibrio fischeri in the Microtox Test

“…The standard sampling technique for dry solids on hard smooth surfaces (Kim et al, 2000) did not work, because the 3-mm inlet of the "lter cassette became blocked by a wet Microtox reagent pebble. The cassette was also too large to allow 1.0 mL of reconstitution solution to dissolve all the solid on the "lter surface, but 2.0 mL did.…”

“…The sampling probe was held with the thumb and index "nger at a 453 angle and a #ow rate of 4.0 L/min. The di!erence in mass of the probe and cassette after sampling relative to that before is the mass collected, and is compared with the mass applied to de"ne sampling e$ciency per sampling pass or over a number of sampling passes (Kim et al, 2000). One sample pass is from along the inner edge of the template area to its center in patterns of squares of progressively decreasing area.…”

“…The sampling method was based on a previously published technique developed by one of the present authors 190 PARK AND QUE HEE (Kim et al, 2000), modi"ed from an earlier one .…”

A Comparison of Two Surface Sample Collection Devices for Use in Polymerase Chain Reaction Based Detection of Pneumocystis carinii in House Dust

“…(25) This method employed a portable, battery-operated pump in conjunction with an air sampling cassette. (24) Their results demonstrated a dust collection ef ciency of greater than 85 percent with good precision (CV < 11%) on hard surfaces. The ef ciency and precision of the collection was independent of particle size in the range of 63 to 180 ¹m and sample load in the range of from 9.3 to 169 mg dust.…”

“…Because of this, the sampling precision tends to be very low. (24) This imprecision can lead to misclassi cation of exposure, resulting in statistically insigni cant associations with various outcomes. Kim et al recently published a dust sampling protocol for the determination of lead concentration in surface dust based on ASTM Method No.…”