Browsing by Author "Shih, Tung-Sheng"

Now showing 1 - 4 of 4

Laboratory and field tests of a novel three-stage personal dust sampler for sampling three dust fractions simultaneously
(2008-01-01)
Tsai, Chuen-Jinn
;
Chang, Cheng-Sheng
;
Chen, Sheng-Chieh
;
Chen, Penny
;
Shih, Tung-Sheng
This study designed and calibrated a novel three-stage personal dust sampler for sampling inhalable, thoracic, and respirable dust fractions simultaneously. The sampler has an annular inlet as the first stage for inhalable dust sampling, two impactors in the second and third stages to classify thoracic and respirable dusts, respectively, and a final filter. Laboratory calibration tests using monodisperse liquid and solid particles showed that with 100 ppi (pores per inch) PUF (porous polyurethane foam) substrates and at the flow rate of 3.2 L/min, the sampling efficiency curves of both impactor stages matched with the ISO/CEN/ACGIH thoracic and respirable sampling criteria, respectively. The sampler also agreed with the inhalable criterion for particles smaller than 17 mu m while the deviation increases with increasing particle diameter with a maximum of 28% for 27 mu m particles. It was also found that collection efficiency curve for solid particles was similar to that of liquid particles, indicating that there was no solid particle bounce from the PUF substrates for both impactors. This study also compared inhalable, thoracic, and respirable dust concentrations measured by the present three-stage personal dust samplers with those of the Respicon samplers at three different workplaces. Without using a correction factor of 1.5 for the extrathoracic dusts of the Respicon, field results showed that the present three-stage sampler measured three dust fractions comparable to those of the Respicon samplers. The inhalable dust concentrations of the two samplers differed within 5% while the thoracic and respirable concentration differed by less than 22%.
Measurement of 2,4-toluene diisocyanate concentrations by different samplers
(2006-10-11)
Tsai, Chuen-Jinn
;
Lin, Hsi-Chen
;
Shih, Tung-Sheng
;
Chang, Kai-Chung
;
Hung, I.-Fu
The standard sampling methods for toluene diisocyanate (TDI) only collect total TDI without separating the aerosol and gas phases. There are few other samplers, such as the dual filter, triple filter and annular denuder systems (ADS), which are able to sample the aerosol and gas phases simultaneously. This field study was conducted at two workplaces to access the total 2,4-TDI and the gaseous and aerosol TDI concentrations by different samplers simultaneously. In addition to the standard sampling time of 15 min, sampling was done for 30 and 60 min to study the effect of sampling time on the measured 2,4-TDI concentrations. Test results at two workplaces show that gas-phase 2,4-TDI is the predominant species and the aerosol phase concentration is very small. The measurements using various samplers show that the sampling time influences the sampled TDI concentration considerably which may be due to reaction of TDI with water vapor and polyo in the sampling process. It is evident that as sampling time increases the TDI concentration decreases. Laboratory test was also conducted using pure gas-phase 2,4-TDI to confirm the sampling time effect on the measured concentrations found in the field study. (c) 2006 Elsevier B.V. All rights reserved.
Measurements of respirable dust and nanoparticle concentrations in a titanium dioxide pigment production factory
(2010)
Huang, Cheng-Hsiung
;
Tai, Chih-Yuan
;
Huang, Cheng-Yu
;
Tsai, Chuen-Jinn
;
Chen, Chun-Wan
This study compared respirable dust and nanoparticle concentrations measured by different sampling devices at a titanium dioxide pigment factory. Respirable particle mass concentrations, nanoparticle concentrations, particle size distribution and particle metallic content were measured at different sampling locations. The sampling results of the Multi-orifice Uniform Deposit Impactor (MOUDI) showed that the particle size distribution at this titanium dioxide production factory fell in the range of 1-10 mu m. Generally, the higher levels of the respirable particle mass concentrations and nanoparticle number concentrations were near the packing site of the pigment titanium dioxide production factory. Metal analysis results revealed that the titanium dioxide concentrations in respirable dust and nanoparticles were within the limits specified by National Institute for Occupational Safety and Health (NIOSH). During sampling, particle metallic content analysis is essential for identifying the source of particles and for measuring respirable dust and nanoparticle concentrations.
Measurements of ultrafine particle concentrations and size distribution in an iron foundry
(2008-10-01)
Cheng, Yu-Hsiang
;
Chao, Yen-Chi
;
Wu, Cheng-Han
;
Tsai, Chuen-Jinn
;
Uang, Shi-Nian
The number and surface area concentration of ultrafine particles in an iron foundry is of interest as freshly generated ultrafine particles are produced by metal melting, pouring and molding processes. This study measured the number and surface area concentrations of ultrafine particles and their size distributions in an iron foundry using a scanning mobility particle sizer (SMPS). The 10-100 nm ultafine particle number concentrations (NC0.01-0.1) and surface area concentrations (SC0.01-0.1) measured at the iron foundry were 2.07 x 10(4) to 2.82 x 10(5) particles cm(-3) and 67.56 to 2.13 x 10(3) mu m(2) cm(-3), respectively. The concentrations changed dramatically depending on on-site manufacturing conditions. The NC0.01-0.1 levels in the iron foundry were approximately 4.5 times higher on average compared with those in the outdoor ambient environment. These measurement results indicate that the presence of extra particles in the workplace air is within the ultrafine range. Additionally, the analytical results suggest that the number mode diameter can be used to estimate the SC0.01-0.1 levels using the NC0.01-0.1 levels. Moreover. the ultrafine particle number mode diameter was found to be about 46.1 nm in the iron foundry. (C) 2008 Elsevier B.V. All rights reserved.