Evaluation of a diffusion charger for measuring aerosols in a workplace.
Vosburgh-DJH; Ku-BK; Peters-TM
Ann Occup Hyg 2014 May; 58(4):424-436
The model DC2000CE diffusion charger from EcoChem Analytics (League City, TX, USA) has the potential to be of considerable use to measure airborne surface area concentrations of nanoparticles in the workplace. The detection efficiency of the DC2000CE to reference instruments was determined with monodispersed spherical particles from 54 to 565.7 nm. Surface area concentrations measured by a DC2000CE were then compared to measured and detection efficiency adjusted reference surface area concentrations for polydispersed aerosols (propylene torch exhaust, incense, diesel exhaust, and Arizona road dust) over a range of particle sizes that may be encountered in a workplace. The ratio of surface area concentrations measured by the DC2000CE to that measured with the reference instruments for unimodal and multimodal aerosols ranged from 0.02 to 0.52. The ratios for detection efficiency adjusted unimodal and multimodal surface area concentrations were closer to unity (0.93-1.19) for aerosols where the majority of the surface area was within the size range of particles used to create the correction. A detection efficiency that includes the entire size range of the DC2000CE is needed before a calibration correction for the DC2000CE can be created. For diesel exhaust, the DC2000CE retained a linear response compared to reference instruments up to 2500 mm2 m-3, which was greater than the maximum range stated by the manufacturer (1000 mm2 m-3). Physical limitations with regard to DC2000CE orientation, movement, and vibration were identified. Vibrating the DC2000CE while measuring aerosol concentrations may cause an increase of approximately 35 mm2 m-3, whereas moving the DC2000CE may cause concentrations to be inflated by as much as 400 mm2 m-3. Depending on the concentration of the aerosol of interest being measured, moving or vibrating a DC2000CE while measuring the aerosol should be avoided.
Nanotechnology; Diffusion-analysis; Airborne-dusts; Airborne-fibers; Airborne-particles; Work-environment; Particulates; Aerosols; Aerosol-particles; Exhaust-gases; Diesel-exhausts; Dusts;
Author Keywords: diffusion charger; nanoparticles; surface area monitor
Donna J. H. Vosburgh, Department of Occupational and Environmental Safety and Health, University of Wisconsin-Whitewater, 800 West Main Street, Whitewater, WI 53190
Annals of Occupational Hygiene
University of Iowa