Collection and characterization of a bulk PM2.5 air particulate matter material for use in reference materials

Abstract

A contemporary PM2.5 (particulate matter smaller than 2.5 microns aerodynamic diameter) aerosol material from an urban site has been collected for the production of a new standard reference material that will be made available for the development of new PM2.5 air quality standards. Air particulate matter corresponding to the PM2.5 fraction was collected at an established Environmental Protection Agency monitoring site in Baltimore, Maryland. The air-sampling system that has been constructed for this collection separates fine particles with a cyclone separator and deposits them onto an array of Teflon membrane filters. The fine air particulate material is removed by ultrasonication or by mechanical means and collected for further preparation of standards. The composition of the collected PM2.5 aerosol, as well as the composition of the deposited PM2.5 aerosol, are determined by instrumental nuclear activation analysis and other techniques.

Involvement of TLR2 and TLR4 in inflammatory immune responses induced by fine and coarse ambient air particulate matter

“…In this study, we used standard air PM samples collected by the NIST (Gaithersburg, MD, USA), and they were characterized according to metal content. The PM 2.5 sample (obtained as a gift) was collected by NIST from 1998 to 2001 in Baltimore, MD, USA, to create an interim standard reference material of fine urban particulate matter (NIST IRM PM 2.5 ) and was collected as described by Heller-Zeisler et al [47], www.cstl.nist.gov/ projects/fy05/e&e05schantz2.pdf. Briefly, a bulk sample of PM 2.5 was collected at an established EPA site in the Clifton Park area of Baltimore on an 8 in ϫ 10 in Teflon filter array, using a high volume 1-m cyclone sampler.…”

Preparation of a PM2.5-like reference material in sufficient quantities for accurate monitoring of anions and cations in fine atmospheric dust

“…This principle was later used to produce NIST SRM 2783. In another paper, the authors used cyclone-based collection on Teflon filters [14]. The latter paper illustrates the major difficulty in obtaining sufficient amounts of material where only 11.5 g was collected over 5 weeks of operation of the cyclone separator.…”

“…Ideally, the material should be authentic air-sampled PM 2.5 . But for the reasons discussed above, an approximation based on, for example, filtration of suspended fine particles, re-suspension of existing particulate matter materials or jet-milling of roadside dust has been used to produce the already existing air particulate matter CRMs from NIST (SRM2783, SRM2786 and SRM2787) and the EC-JRC (ERM-CZ100 and ERM-CZ120), respectively [10, 11, 13, 14]. …”

“…According to the Mason-Weaver equation, particles with larger hydrodynamic diameters sediment at a higher speed than smaller particles [16]. This approach is based on a wet route where some alteration of the chemical composition is inevitable because soluble components are dissolved, as pointed out by Heller-Zeiser et al [13, 14]. On the other hand, since the solvent (water) is removed during spray drying, the solutes will adsorb back onto the particles during drying in contrast to a method only based on filtration [13].…”