Development of a Personal Sampler for Evaluating Exposure to Ultrafine Particles

Abstract

Evaluation of the exposure of humans to ultrafine, airborne particles is an important aspect of health in the workplace, especially in cases where nano-particles are present. However, portable sampling devices for efficiently collecting ultrafine particles in a worker's breathing zone are not readily available. The present study describes the design and development of a portable sampler for collecting particulates in the breathing zone, as a possible tool for this purpose. The design is based on the use of an "Inertial Filter" to separate various-sized nano-order particles. Inertial filters consisting of SUS fiber felt (fiber diameter 5.6-13.5 μm) placed in circular nozzles (3-6 mm diameter with 4.5 mm length) were used. To achieve the smallest dp50 under the allowable pressure drop of a portable pump, the influence of fiber loading on separation performance and pressure drop were investigated. The influence of particle loading was also examined in relation to pressure drop and separation performance. The smallest dp50 under the allowable pressure drop (5.7 kPa at 6 L/min) for the battery pump employed was ~140 and 200 nm respectively for SUS fibers of 5.6 and 9.8 μm diameter (particle volume fraction ~0.013). The change in separation performance due to particle loading was confirmed to be acceptable for use under the present conditions. Under these conditions, a sufficient amount of particles can be collected for chemical analyses, e.g., particle-bound PAHs after 6-8 hours of sampling. Hence, the developed sampler has the potential for use in evaluating exposure to ultrafine particles in the breathing zone in the workplace.

Performance Evaluation of an Andersen Cascade Impactor with an Additional Stage for Nanoparticle Sampling

“…Based on the results of lab and field tests by the authors (Furuuchi et al, 2009;Hata et al, 2009b), a sampler, which consisted of impactor stages of PM 10 /PM 2.5 /PM 1 /PM 0.5 followed by an inertial filter stage was developed (Furuuchi et al, 2010a) and commercialized (KANOMAX, 2012). The authors also developed a personal sampler to evaluate exposure to nano-particles based on the inertial technology (Furuuchi et al, 2010b). The inertial filter technology may have possibilities beyond its application to the original Nanosampler (NS), such as devices that could be used to supplement existing samplers such as the Andersen cascade impactor and the high-volume air sampler.…”

Evaluation of Artifacts Generated during Collection of Ultrafine Particles Using an Inertial Filter Sampler

“…After these four impaction stages, particles pass through a cartridge packed with stainless steel fibers at a high flow rate (40 L min -1 ) to promote inertial collection with decreasing diffusion force; the UFPs are separated and led to a backup polytetrafluoroethylene (PTFE) filter, then are collected uniformly onto a 47 mm φ quartz fiber filter. The pressure loss in this sampler is approximately 20 kPa, which is lower than that of a LPI sampler (about 70 kPa) (Furuuchi et al, 2010a). The low pressure loss and uniform collection of UFPs suppresses the volatilization of unstable components and improves the accuracy of component analysis after filter punching.…”

Air Pollution, Allergic Co-morbidity, and Emergency Department Visit for Pediatric Asthma in Taiwan

“…Second, exposure assessment error is inherent in all large epidemiologic studies of district-scale air pollution health effects. Although studies of personal exposure to air pollutants help to advance the understanding of biological responses (Furuuchi et al, 2010), from a regulatory standpoint, the ambient concentrations are of greatest relevance. One prominent component of error in our studies, therefore, is how well the population-weighted spatial average of assessments from monitoring stations approximates the ambient concentration across the entire metropolitan northern Taiwan area.…”