Assessing Challenges Associated with Sampling Hexavalent Chromium Under New Consensus Guidelines
Technical Report,01 Oct 2018,26 Mar 2020
AIR FORCE INSTITUTE OF TECHNOLOGY WRIGHT-PATTERSON AFB OH WRIGHT-PATTERSON AFB United States
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A consensus body recently suggested lowering the threshold limit value TLV for hexavalent chromium to 0.2 gm3 and added a requirement to sample using an inhalable sampler. In order to generate enough mass to be above the limit of quantification, it is suggested practitioners increase the flow rate of the sampling pump. Since the sampler was designed to operate at 2 Lmin to adhere to the inhalable convention, there is a possibility the higher flow rates will cause the sampler efficiency to deviate from the convention. An aerosol chamber was constructed and characterized to create well-defined test bed. The aerosol properties of abrasive blasting processes were characterized to determine if particle distribution and composition warranted the use of an inhalable sampler. Results from the aerosol characterization show that all particle sizes carried some chromium and the distribution included particles up to 100 m. Institute of Medicine IOM inhalable samplers were paired, with one sample operating at 2 Lmin and one sampler operating at 6 Lmin. The pairs were exposed to particulate with an aerodynamic diameter of 70 m in the aerosol chamber. Results show a 30 positive difference in the concentrations reported at 6 Lmin compared to 2 Lmin.
- Physical Chemistry
- Test Facilities, Equipment and Methods