Chuen-Jinn Tsai

• ph. D.
• Chair at National Yang Ming Chiao Tung University

Size-segregated sampling of particulate matter (PM) using impactor suffers from D50 cutoff shift due to particle loading and re-entrainment problems. Cyclonic separation is a viable option to overcome the above problem. However, conventional reverse flow cyclone design having a single inlet and upward-facing outlet also presents a common issue of s...

This study assessed the machine learning based sensitivity analysis coupled with source-apportionment of volatile organic carbons (VOCs) to look into new insights of O3 pollution in Yunlin County located in central-west region of Taiwan. One-year (Jan 1 to Dec 31, 2021) hourly mass concentrations data of 54 VOCs, NOX, and O3 from 10 photochemical a...

The study aimed to investigate the PM2.5 variations in different periods of COVID-19 control measures in Northern Taiwan from Quarter 1 (Q1) 2020 to Quarter 2 (Q2) 2021. PM2.5 sources were classified based on long-range transport (LRT) or local pollution (LP) in three study periods: one China lockdown (P1), and two restrictions in Taiwan (P2 and P3...

A scarce distribution of the PM2.5 chemical compositions monitors reduces the applicability of scientific information for policymakers to assess the effectiveness of air pollution control strategies. There is an urgent need for a spatial-temporal prediction model for characterizing PM2.5 chemical compositions to assess exposure risks and develop ef...

Filter-based devices were found to underestimate PM2.5 mass concentrations due to the evaporation loss of semi-volatile inorganic materials (SVIM). To reduce the evaporation-induced PM2.5 loss, the chilled Teflon filter sampler (CTF) was developed in which the sampling air was chilled to low temperatures (T) of 4–7 °C after dehumidification. The CT...

A laboratory scale, 1.0 CMM (m ³ min − 1 ) wet scrubber packed with water-absorbing honeycomb material (HWS) with a very large geometric surface area of 480 m ² m − 3 and a low pressure drop developed in our previous study was shown to achieve a very high removal efficiency for acidic gases but there were no long-term test data. In this study, the...

The classical theory for the diffusional loss of aerosol particles in a fully developed laminar flow through a circular tube derived by Gormley and Kennedy (1949) did not consider the slip-flow condition. However, the non-slip condition for the gas velocity boundary condition may not be appropriate for the gas flow in microgeometries such as microc...

Particle size classifiers are widely used to separate particles at a certain aerodynamic diameter below which particles are used for various purposes. However, it is hard for current available classifiers to achieve nanoparticle classification at high particle mass loading conditions in addition to the cost of high pressure drop. In this study, a n...

Capturing and recovering naphthalene as a profitable chemical from hot flue gas are of significance in terms of environmental protection with economic benefits, for which the adsorption technology using high-performance sorbents provides the key step for success in practical applications. Carbonaceous materials with hydrophobic natures have been sh...

To evaluate the performance of low-cost PM2.5 sensors and develop calibration models for correcting for the PM2.5 sensor data (PM2.5,S), field comparison tests were conducted based on Met One BAM-1020 data at various locations using long-term (≥one year) data of Plantower PMS5003, Sensirion SPS30, and Honeywell HPMA115S0 PM2.5 sensors. Both multiva...

With the increasing interest in manufacturing nano-sized metal particles in large quantities for their numerous applications in industry, medicine and daily life as well as nanotoxicity testing, there is a critical demand to improve methods to generate nanoparticles with controllable nano-size and high number concentrations. Here, a stable method f...

Inertial impactors are applied widely to classify particulate matters (PMs) and nanoparticles (NPs) with desired aerodynamic diameters for further analyses due to their sharp cutoff characteristics, simple design, easy operation, and high collection ability. A few hundred papers have been published since the 1860s that addressed the characteristics...

A laboratory scale, 1.0 CMM wet scrubber packed with water-absorbing honeycomb material (HWS) with a very large geometric surface area of 480 m ² m ⁻³ and a low pressure drop developed in our previous study was shown to achieve a very high removal efficiency for gaseous acidic gases but there were no long-term test data. In this study, the HWS scal...

A semi-continuous monitoring system, a parallel plate wet denuder and particle into liquid sampler coupled with ion chromatography (PPWD-PILS-IC), was used to measure the hourly precursor gases and water-soluble inorganic ions in ambient particles smaller than 2.5 µm in diameter (PM2.5) for investigating the thermodynamic equilibrium of aerosols us...

Most of PM2.5 FRM samplers and FEM monitors use a well impactor ninety-six (WINS) or very sharp cut cyclone (VSCC) to classify particles smaller than 2.5 μm in diameter. However, the WINS has the particle loading effect and needs to be cleaned after 3 to 5 sampling days. The VSCC was claimed not to be affected by the particle loading effect in a la...

A PM2.5 high-volume impactor (HVI) sampler is developed, which has a flow rate of 1130 L per minute (lpm) (1.13 m³/min) and in it, the filter size used is of 8 inch × 10 inch. The major advantages of this sampler as compared to other low-volume sampler (flow rate 16.67 lpm) are lower uncertainty in mass measurement, higher PM2.5 mass collection and...

A numerical model was used to study the homogeneous nucleation process of dibutyl phthalate (DBP) vapor in a laminar flow diffusion chamber (LFDC); the spatial and temporal evolution of DBP droplet size distribution was governed by the population balance equation (PBE). In the PBE, the nucleation rate was calculated by the self-consistent correctio...

Adsorption as one of the most important air cleaning methods has been extensively applied during which the coexisting airborne nanoparticles (NPs) with sizes close to adsorbent pore sizes could inevitably influence gas adsorption processes. In this work, the influence of sub-20 nm NPs on toluene adsorption on ZSM-5 zeolites exchanged with different...

Increasing applications of multi-walled carbon nanotube (MWCNT) lead to significant occupational exposure and potential health concern. Toxicity of MWCNT should be carefully elucidated since conventional (CON) method with fully immersed condition fails to mimic the air-liquid interface (ALI) in airways. Additionally, quantification of MWCNT in cell...

Loading experiments of four electret fibrous media having various properties, including fiber diameter, porosity, thickness, charging density and fibrous structure, with fine and nanosized particles were conducted for finding out the influencing factors on efficiency decline and particle holding capacity. The four media include a commercial HVAC me...

The particle mass measurement instrument of the aerosol particle mass analyzer (APM) tends to underestimate the particle mass of sub-50 nm nanoparticles, limiting the APM mass measurement to larger particles. In the present work, a mass correction method was developed based on a calibration reference to correct the APM mass underestimation accordin...

Gaseous polycyclic aromatic hydrocarbons (PAHs) are carcinogenic and mutagenic pollutants and also able to promote the growth of secondary particulate matters which have attracted great attention in recent years. Control of PAHs emissions in exhaust gases using different techniques has been hot topics in the atmospheric environment field. Adsorptio...

The louvered 16.7 L min⁻¹ PM10 inlet is commonly used in PM10 and PM2.5 FRM samplers or FEM monitors. Its sampling efficiency is influenced by particle bounce, re-entrainment, and overloading since the PM10 inlet contains a PM10 impactor with an uncoated impaction surface. In this study, a modified PM10 (M-PM10) inlet with an oil-soaked glass fiber...

The removal characteristics of sub-25 nm ultrafine particles (UFPs) by different porous nanomaterials with different morphologies were studied based on efficiency curves obtained with specially designed filtration system. The material morphological effects on UFPs collection were investigated. The results demonstrate a complex and synergic mechanis...

A device to monitor particulate matter of size 2.5 μm (PM2.5) that has been designed and developed includes a surface-acoustic-wave sensor operating in a shear horizontal mode (SH-SAW) combined with a cyclone separator. In our tests, aerosols generated as incense smoke were first separated and sampled inside a designed cyclone separator; the sample...

This study characterized the process by-product particles (mostly nanoparticles) released during the preventive maintenance of semiconductor fabrication facilities, such as chemical mechanical planarization (CMP), plasma-enhanced chemical vapor deposition (PECVD), and ion implantation. Manual sampling and real-time measurements with direct reading...

Modelling dynamic adsorption of sulfur dioxide (SO2) on activated carbons (ACs) is significant in guiding practical desulphurization processes and making highly efficient use of adsorbents in terms of the adsorption rate which largely depends on particle size. In this work, models derived from the Vermeulen and an improved linear driving force (LDF...

Airborne ultrafine nanoparticle (UFNP) is a key factor causing heavy haze pollution in Beijing-Tianjin-Hebei, which is very harmful to human health and the environment. Removal of environmental UFNPs by porous material is an important method of air purification treatment. However, the specific mechanism by which porous material filters UFNPs is not...

The aerosol mass measurement method, DMA-APM, measures a lower mass as compared to the electrical mobility diameter-based particle mass for sub-50 nm nanoparticles. The extent of underestimation increases with decreasing nanoparticle diameter and can reach as much as 20–80% for different nanoparticles between 10–20 nm. To study this issue, the DMA-...

There are 16 manuscripts submitted to this special issue from the papers presented in the conference or relevant to the gas filtration area. After peer review, only 9 papers are accepted and published in this special issue. Aerosol filtration is currently one of the most economical and effective ways for particle control. Four papers in this specia...

The impaction well containing an oil-soaked glass fiber (GF) filter of the well impactor ninety-six (WINS) needs to be replaced every five sampling days to avoid particle overloading which affects the cutoff diameter (dpa50) and the sampling accuracy. This study developed a novel modified WINS (M-WINS) which uses water to wash the wetted GF filter...

There is an increasing demand of air filters with a high collection performance, i.e., high collection efficiency and low pressure drop, for the application to indoor air cleaning. Air filters consisting of nanofibers have attracted great interests since they may have a low pressure drop because of slip flow effect and high collection efficiency du...

Adsorptive removal of the predominant polycyclic aromatic hydrocarbons (PAHs), represented by phenanthrene, from hot gases using mesoporous adsorbents (mesosilicas MCM-41 and SBA-15, and mesocarbon CMK-3) has been studied through tests of column adsorption and temperature programmed desorption (TPD). Adsorption equilibria on MCM-41 and CMK-3, and o...

The Asian Aerosol Conference (AAC), held every two years, is the most prestigious conference for aerosol researchers in Asian region. The 9th AAC (AAC 2015) was held by Japan Association of Aerosol Science and Technology (JAAST) on behalf of Asian Aerosol Research Assembly (AARA) from June 24 to 27, 2015 at Kanazawa, Japan. A total of 520 participa...

An automated system consisting of a particle-into-liquid sampler (PILS) and a parallel plate wet denuder (PPWD) coupled with an ion chromatography was used for simultaneous measurement of ambient water-soluble ions in PM 2.5 and precursor gases. The performance of the PPWD/PILS was validated by comparing it with the PDS (porous metal denuder sample...

To investigate the impact of biomass burning emissions on ultrafine particles (PM0.133: particulate matter with an aerodynamic diameter less than 0.133 μm), biomass burning tracers (including levoglucosan, mannonsan and K⁺) were measured at a rural and an urban sites in Xi'an during winter heating period. The average levoglucosan concentrations of...

Natural and human activities generate a significant amount of PM2.5 (particles ≤2.5 µm in aerodynamic diameter) into the surrounding atmospheric environments. Because of their small size they can remain suspended for a relatively longer time in the air than coarse particles and thus can travel long distances in the atmosphere. PM2.5 is one of the k...

Natural and human activities generate a significant amount of PM2.5 (particles ≤2.5 μm in aerodynamic diameter) into the surrounding atmospheric environments. Because of their small size, they can remain suspended for a relatively longer time in the air than coarse particles and thus can travel long distances in the atmosphere. PM2.5 is one of the...

Ambient aerosol nano-particles have been getting an increasing attention from their health risk point of view.  Not enough information on the status and characteristics of ambient aerosol nano-particles as well as their emission sources yet. Status and characteristics of ambient aerosol nano-particles have not been compared between different locat...

As China is receiving an economic boom, PM (particulate matter) pollutions not only have become a serious regional problem but also frequently impacted its neighboring counties, e.g., Korea and Japan. In addition to its adverse effects on human health, the on- and off-road engines operated in ambient can also be affected. In this study, a simple sy...

The carbonaceous aerosol concentrations in coarse particle (PM10: Dp ≤ 10 μm, particulate matter with an aerodynamic diameter less than 10 μm), fine particle (PM2.5: Dp ≤ 2.5 μm), and ultrafine particle (PM0.133: Dp ≤ 0.133 μm) carbon fractions in a rural area were investigated during haze events in northwestern China. The results indicated that PM...

The adsorption isotherms of naphthalene on three typical mesoporous adsorbents, MCM-41, SBA-15 and CMK-3 at 125 °C were determined by column tests, with feed concentrations ranging from 7.63×10-5 to 4.64×10-2 mol·m-3 (1.88 to 1140 ppm). The Langmuir model and constant-pattern wave propagation model were found to well fit the isotherms and the break...

The desorption performances of naphthalene and pyrene on mesoporous MCM-41, SBA-15 and CMK-3 sorbents are studied, based on temperature programmed desorption experiments over the temperature range of 350−800 K at different heating rates. The kinetic parameters for each sorbate−sorbent pair are determined with combined model fitting methods. The dat...

In this study, long term measurements of PM2.5 and ultrafine particles (UFPs) for daily average mass concentration at Zhongshan (ZS), Sinjhuang (SJ), and Jhudong (JD) urban air monitoring stations were conducted from 2011 spring to 2013 autumn. The results showed that daily average UFPs mass concentrations in spring (average at 3 stations: 1.58 ± 0...

The NCTU micro-orifice cascade impactor (NMCI) was redesigned and tested to enable the measurement and adjustment of the jet-to-plate distance (S) of the impactors by using a micrometer. Each stage of the NMCI contains an impaction plate and a nozzle plate which are separated. The bottom casing for impaction plate assembly and the nozzle plate hold...

A new wire-on-plate electrostatic precipitator (WOP-EP) where discharge wires are attached directly on the top of a dielectric plate surface was developed to ease the installation of the wires, minimize particle deposition on the wires, lower ozone emission while maintaining a high particle collection efficiency. For a lab-scale WOP-EP (width: 50 m...

The evaporation losses of PM2.5 particles in eight different size ranges corresponding to the 4th–10th stages and after filter of the MOUDI were calculated theoretically and then integrated to obtain the total PM2.5 evaporation loss. Results show that when PM2.5 particles are nearly neutral with pH in the range of 7–8, the evaporated concentrations...

Fernández-Díaz and Domat's preceeding Letter to the Editor argued that the geometry of the discharge electrode of the charger of our previous article entitled “Modeling and Validation of Nanoparticle Charging Efficiency of a Single-Wire Corona Unipolar Charger” was a needle but not a wire. Therefore, the boundary condition for the ionic charge dens...

An efficient wire-to-plate single-stage wet electrostatic precipitator (WESP) was designed and tested to control nanoparticles, submicron and micron-sized particles emitted from semiconductor manufacturing processes. Tungsten-wires of 0.36 mm in diameter were used as discharge electrodes and a fixed voltage of −15 kV was supplied to generate the el...

Understanding the characteristics of the size distribution of ambient black carbon (BC) in distinct environments is critical because the influence of BC aerosols on climate, visibility, and human health depends strongly on the distribution of BC aerosols over the particle size spectrum. In this study, a novel method for determining the mass size di...

The comprehensive analysis of chain mechanism development in the Al–H2O system is performed on the base of novel reaction mechanism taking into account quantum chemistry studies of potential energy surfaces of the elementary reactions with Al-containing species and estimations of rate constants of corresponding reaction channels. As well the physic...

The existing theoretical response spectra of APM-3600 agree well with the experimental data for submicron particles larger than 100 nm in the electrical mobility diameter but not for nanoparticles. In this study, a 2-D numerical model was developed to predict the transfer function and response spectra of APM-3600 based on the detailed simulation of...

Traffic emissions are a significant source of airborne particulate matter (PM) in ambient environments. These emissions contain high abundance of toxic metals and thus pose adverse effects on human health. Size-fractionated aerosol samples were collected from May to September 2013 by using micro-orifice uniform deposited impactor (MOUDI). Sample co...

The binary diffusion coefficients of two low lying isomers of (Al2O3)n , n = 1...4, clusters in different bath gases, that most frequently met in the nature and in the technical applications: H2, N2, O2, CO, H2O as well as their self-diffusion coefficients have been calculated on the basis of kinetic theory and dipole reduced formalism. The paramet...

A nozzle plate containing multiple micro-orifices for the cascade impactor and a method for manufacturing the same are disclosed. The nozzle plate is formed by a series of semiconductor processes, including lithography, etching and electroplating. The nozzle plate comprises a plate body and a plurality of micro-orifices formed on the plate body. Th...

Field studies were conducted at Taiwan National Chiao-Tung University (NCTU) campus to evaluate the evaporation loss of fine particles (PM2.5) collected by the multi-filter PM10–PM2.5 sampler (MFPPS), which was collocated with a dichotomous sampler (Dichot, Andersen, Model SA-241), a WINS PM2.5 sampler (Thermo, Model 2000-FRM), and a tapered elemen...

The multipoint-to-plane electrostatic precipitator (ESP) is one type of ESP devices used for the sampling and control of nanoparticles and sub-micron particles, with the advantage of a low pressure drop and high particle collection efficiency. Several empirical equations for predicting the particle collection efficiency are available in the literat...

By modulating the Earth-atmosphere energy, hydrological and biogeochemical cycles, and affecting regional-to-global weather and climate, biomass burning is recognized as one of the major factors affecting the global carbon cycle. However, few comprehensive and wide-ranging experiments have been conducted to characterize biomass-burning pollutants i...

There are several exciting developments noted in gas and aerosol measurements in recent years. On the other hand not much work has been done on the calibration facility, traceable standards, and certified reference materials for this field of science. More attention and concerns are needed for the comparable and SI traceable data quality in gas and...

The influence of particle morphology on the accuracy of nanoparticle size distributions measured by the engine exhaust particle sizer spectrometer (EEPS, TSI Model 3090) was studied using the scanning mobility particle sizer (SMPS, TSI Model 3936) as a reference. The EEPS shows higher total number concentrations with the maximum relative difference...

In this study, PM2.5 concentrations were measured simultaneously by a Dichotomous sampler (Dichot, Model SA241, Andersen Inc., Georgia, USA) (PM2.5,D) and a beta attenuation monitor (BAM) (PM2.5,B) at each of three air monitoring stations in Taiwan. Results show that PM2.5,B concentrations measured by the VEREWA-F701 BAM (without federal equivalent...

The concentrations of PM2.5 carbon fractions in rural, urban, tunnel and remote environments were measured using the IMPROVE thermal optical reflectance (TOR) method. The highest OC1 and EC1 concentrations were found for tunnel samples, while the highest OC2, OC3, and OC4 concentrations were observed for urban winter samples, respectively. The lowe...

A venturi scrubber which avoids clogging in the throat by dust particles is developed. The scrubber includes a venturi tube, two scrubbing fluid conduits and a storage tank. The venturi tube has a converging section, a diverging section and a throat section which is connected between the converging section and the diverging section. The scrubbing f...

A personal nanoparticle sampler (PENS) that simultaneously collects respirable particles (< 4 μm) and nanoparticles (< 0.1 μm) has recently been developed and calibrated in the laboratory. This study aims to evaluate the performance of the PENS in the workplace, and to determine the exposure characteristics during selected metalworking operations....

A single-wire corona unipolar charger with radial sheath air was proposed to enhance the nanoparticle charging efficiency. The charger consists of an insulated Teflon tube (inner diameter = 6.35 mm) with a 6 mm-long grounded porous metal tube placed at its center from which radial sheath air is introduced, and a discharge gold wire of 50 μm in the...

A particle charger with sheath air flow for enhancing charging efficiency includes a housing and a discharge wire. The housing has a charging chamber for accommodating the discharge wire, a particle inlet, a sheath air inlet, an outlet and an accelerating channel. A clean sheath air is guided through the sheath air inlet into the charging chamber t...

This work investigated the performance in terms of collection efficiency and aspiration efficiency of a personal sampler capable of collecting ultrafine particles (nanoparticles) in the occupational environment. This sampler consists of a cyclone for respirable particle classification, micro-orifice impactor stages with an acceleration nozzle to ac...

In this study, two micro-orifice-based cascade impactors, including the micro-orifice uniform deposit impactor (MOUDI, MSP Model 110) and the NCTU micro-orifice cascade impactor (NMCI), were tested for the collection efficiency and interstage loss of nanoparticles. In the NMCI, new nozzle plates with smooth nozzle shape made by the LIGA (Lithograph...

The positive artifacts in particulate organic carbon fractions for fine particles (PM2.5) and nanoparticles (PM0.1) were characterized in a tunnel environment by using the QBQ (a quartz filter behind a quartz filter) method. The OC concentrations of the backup quartz filters ranged from 3.56 to 11.38 μg m−3 with the average of 6.70 μg m−3 for PM2.5...

In this study, nanoalumina and nanoclay particles were compounded separately with ethylene vinyl acetate (EVA) polymer to produce nanocomposites using a twin-screw extruder to investigate exposure and effective controls. Nanoparticle exposures from compounding processes were elevated under some circumstances and were affected by many factors includ...

It is generally thought that East Asia dominates the supply of eolian dust to the North Pacific. Here we show the first data-based evidence of dust primarily from non-East Asian sources even during March 2010 when a super dust storm from East Asia struck the western Pacific. Chemical characteristics of aerosol samples collected at a high-mountain s...

Ambient Particulate Matters (PM10, PM2.5 and PM0.1) were investigated at Shinjung station in New Taipei City, Taiwan. Samples were collected simultaneously using a dichotomous sampler (Andersen Model SA-241) and a MOUDI (MSP Model 110) over a 24-h period from May 2011 to November 2011 at Shinjung station. Samples were analyzed for metallic trace el...