Particle Elemental Composition Research Articles

A sampler designed for nanoparticles and respirable particles with direct analysis feature

A sampler has been designed to collect particles in the nanometer and respirable sizes directly onto a membrane filter and transmission electron microscopy (TEM) grid. The novel design aspects of this sampler include the selection of the diameter of the inlet probe, geometry of the sampler, and the resulting air flow to the sampler. Together, they control the cutoff diameter, which was determined experimentally to be a mass median aerodynamic diameter (MMAD) of 3.8 μm. The maximum aerodynamic diameter entering the sampler is designed to be approximately 8 μm. Nanometer-sized particles are collected on both the filter and grid through diffusion, as confirmed by testing with aluminum oxide engineered nanoparticles collected on the filter which measured a count median diameter (CMD) of 500 nm and a geometric standard deviation (GSD) of 1.97. The primary particles and small agglomerates collected on the grid have a CMD of 100 nm and GSD of 2.3. This diffusion sampler collected close to, if not 100%, of the particles entering the sampler. The sampler is easily wearable for personal exposure and environmental sampling, operates at 0.3 L/min, and can collect particles in various settings at indoor and outdoor environments. Particles are analyzed directly by transmission electron microscope on the grid and by scanning electron microscope on the filter to assess the exposure through particle counts and elemental composition analysis.

Enhancing lead removal from water by complex-assisted filtration with acacia gum

In this work, for the first time, the use of AG as a natural, widely available and cheap material to enhance the removal of lead from contaminated water using polymer-enhanced membrane filtration (PEMF) has been carried out. In this technique, heavy metal ions are chelated with high molecular weight water-soluble polymers with following rejection of the formed polymer-metal complexes with the wide-porous and high flux polymer membranes. Acacia gum (AG) is a natural gum, which is collected from the hardenedsapof some species of the acacia tree. The surface area particle sizes, zeta potential and elemental composition of AG were evaluated using BET, FE-SEM, zeta potential analyzer, EDS and XPS methods. The effect of AG dosage, lead concentration, feed pH, and contact time on lead-AG complex formation has been studied. The highest binding capacity of AG was about 12.2 mg/g when 1000 ppm AG was added to 35 ppm lead solution at pH 7. It was found that, with a dosage of 1000 mg/L of AG at pH 7, successful lead removal efficiencies of 97.5%, 98.3% and 99.9% were achieved using microfiltration polytetrafluoroethylene (PTFE), 30 kDa and 3 kDa molecular weight cut-off ultrafiltration cellulose membranes, respectively. The possible mechanism of lead removal with AG has been discussed. The obtained data have shown that AG can be used as a safe and cheap chelating agent for lead removal from water.

Investigation of characteristics of solid particles from a mixture of sewage sludge and wood pellets synthetic gas and their clean-up

The most reasonable way to utilise sewage sludge in Europe is in energy production. In the process of thermochemical conversion of sewage sludge, combustible gas is produced. Studies of synthetic gas composition show that this gas contains various impurities, which must be cleaned before gas supply to the final user. Although there are many ways to clean toxic materials existing in the synthetic gas, the application of plasma treatment seems the most promising. Exposure to the high temperature of plasma changes the structure and the chemical composition of solid particulates existing in the gas. In this study on the synthetic gas, ESP cleaning efficiency, size and elemental analysis of solid particles collected from different parts of the experimental setup with a gasifier operating on a mixture of sludge and wood pellets were analysed. The results showed the difference in particle sizes and changes in elemental composition of particles collected from different parts of the experimental setup. It was determined that the synthetic gas obtained by gasification of a mixture of sludge and wood pellets contains a great concentration of solid particles, which leads to the total collection efficiency of an electrostatic precipitator being only about 60%.

Synthesis of silver-containing calcium aluminate particles and their effects on a MTA-based endodontic sealer

ObjectiveTo synthetize calcium aluminate (C3A) and silver-containing C3A particles (C3A+Ag) testing their effects on the properties of a MTA-based endodontic sealer in comparison to an epoxy resin- and a calcium silicate-based sealer. MethodsPure C3A and C3A+Ag particles were synthesized by a chemical method and characterized using XRD to identify crystalline phases. SEM/EDS analysis investigated morphology, particle size, and elemental composition of particles. Setting time, flow, radiopacity, water sorption and solubility of commercial and modified sealers were evaluated according to ISO 6876/2012. The pH and ions release were measured using a pHmeter and a microwave induced plasma optical emission spectrometer. The inhibition of biofilm growth was evaluated by confocal laser scanning microscopy (CLSM). Data were rank transformed and analyzed by ANOVA and Tukey test (P<0.05). ResultsThe C3A particles showed an irregular grain agglomerated structure with voids and pores. In C3A+Ag particles, Ag modified the material morphology, confirming the deposition of Ag. The physicochemical properties of the modified MTA-based sealer were similar to the commercial material, except for the significant increase in Ca+2 release. However, there was no Ag release. Setting time, flow, radiopacity, water sorption and solubility were adequate for all materials. All the materials showed alkaline pH. Antibiofilm effect was improved in the presence of C3A particles, while the biofilm inhibition was lower in the presence of Ag. SignificanceThe modified sealer presented improved antibiofilm properties and calcium release, without dramatic effects on the other characteristics. It is expected a positive effect in its antimicrobial behavior.

On the particle evolution in iron pentacarbonyl loaded counterflow methane–air flame

The present work analyzes these particle evolution processes along the plane axis in an iron precursor (iron pentacarbonyl) loaded methane/air counterflow diffusion flame. The addition of iron pentacarbonyl into methane led to the formation of iron-based nanoparticles in the flame, together with the pre-existing soot particles. These two types of nanoparticles were found to be distinct in their shapes, chemical compositions, geometric mean particle diameters, total particle number concentrations, and particle size distributions. Nanoparticles produced in the flame were sampled from various axial and radial locations by means of a vacuum pump and their particle size distributions were characterized using a scanning mobility particle sizer (SMPS). The representative nanoparticle samples were also collected on the probe and examined using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDAX). SMPS, SEM and EDAX analysis revealed the nucleation, growth, agglomeration and interaction of these nanoparticles formed in the flame, evidenced by the changes of particle morphology, averaged particle size and elemental composition. Adding iron precursors was found to promote particle inception, leading to a greater total particle number concentration but a smaller mean particle diameter. Near the flame location, combustion of soot particles was accelerated due to the catalytic role of iron-based nanoparticles, which agrees the observation of primarily smaller iron-based nanoparticles dominating in the particle population. These findings shed light in studying the engine performance when the fuel borne catalysts are injected for abating particulate matters (PM) during regeneration of Diesel Particulate Filters (DPFs).

Mechanistic understanding of surface reduction of Cu Ce O hybrid nanoparticles for catalytic methane combustion

Abstract The synergistic effect of Cu Ce O hybrid nanostructure has shown the promise for catalytic methane combustion. In this study, we develop an aerosol-based two-stage thermal treatment method to (1) synthesize the Cu Ce O hybrid nanoparticle (NP) with a tunable oxidation state directly in gas phase, and (2) provide a mechanistic understanding of surface reduction of the Cu Ce O hybrid NP for catalysis of methane combustion. After evaporation-induced self-assembly followed by a thermal decomposition to form metal oxide NP at the 1st stage thermal treatment, a temperature-programmed, aerosol-based hydrogen reduction process was employed for direct tuning the oxidation state of the NP in the gas phase (the 2nd stage thermal treatment). Differential mobility analysis, x-ray diffractomery, x-ray photoelectron spectroscopy, and scanning electron microscopy were employed complementarily for characterization of particle size, morphology, crystallinity, elemental composition, and oxidation state of the NPs. The results show a successful surface reduction of Cu for both Cu-only NP and Cu Ce O hybrid NP by the aerosol-based two-stage thermal treatment method. Using the Cu Ce O hybrid nanoparticle as catalyst, our results show a successfully catalysis on methane combustion over various initial oxidation states of Cu. The results show a high activity with a low light-off temperature, a high light-off stability and operation stability toward catalytic methane combustion. The prototype method proposed in this study provides the mechanistic understanding of the synergistic catalysis of the surface-reduced Cu Ce O hybrid nanoparticle with different oxidation states. The method can be especially useful to fabricate a variety of nanocatalysts with different oxidation states of active metals by design for the study of methane-based energy and environmental applications (e.g., CO2 dry reforming by methane).

Ambient Particulate Matter Concentration Levels and their Origin During Dust Event Episodes in the Eastern Mediterranean

The eastern Mediterranean region is strongly influenced by long-range transported particulate matter such as desert dust from northern Africa. To investigate the dynamics of Saharan dust events and their origin, satellite images from the MODIS spectroradiometer of NASA’s satellites Terra and Aqua, and back trajectories analysis of the HYSPLIT model were combined together with continuous ground-based field data. Field PM10 and PM2.5 measurements were performed in the period 2003–2013 at the Akrotiri monitoring station on the island of Crete (Greece). Furthermore, the mineralogical composition of a small number of samples was determined by X-ray powder diffraction, whereas elemental particle composition analysis was performed on the dust samples collected using the ICP-MS technique for a series of elements. The annual average percentage of days with Sahara dust outbreaks in the region of western Crete (Akrotiri station) was 9.3% for the period 2003–2013. Excluding the PM10 exceedances caused by Sahara dust events, the average PM10 monthly concentrations are decreased by 20.5% during the 8-month period November–June, with higher PM10 concentration reduction (29.9%) in the period February–April. Mineralogical analysis showed that illite was the most abundant mineral identified in all samples, followed by quartz and calcite. Gypsum was detected only in the dry sample. Moreover, the elemental particle composition analysis showed that collected dust originated from Africa deserts.

Size-segregated urban aerosol characterization by electron microscopy and dynamic light scattering and influence of sample preparation

Size-segregated particulate matter (PM) is frequently used in chemical and toxicological studies. Nevertheless, toxicological in vitro studies working with the whole particles often lack a proper evaluation of PM real size distribution and characterization of agglomeration under the experimental conditions. In this study, changes in particle size distributions during the PM sample manipulation and also semiquantitative elemental composition of single particles were evaluated. Coarse (1–10 μm), upper accumulation (0.5–1 μm), lower accumulation (0.17–0.5 μm), and ultrafine (<0.17 μm) PM fractions were collected by high volume cascade impactor in Prague city center. Particles were examined using electron microscopy and their elemental composition was determined by energy dispersive X-ray spectroscopy. Larger or smaller particles, not corresponding to the impaction cut points, were found in all fractions, as they occur in agglomerates and are impacted according to their aerodynamic diameter. Elemental composition of particles in size-segregated fractions varied significantly. Ns-soot occurred in all size fractions. Metallic nanospheres were found in accumulation fractions, but not in ultrafine fraction where ns-soot, carbonaceous particles, and inorganic salts were identified. Dynamic light scattering was used to measure particle size distribution in water and in cell culture media. PM suspension of lower accumulation fraction in water agglomerated after freezing/thawing the sample, and the agglomerates were disrupted by subsequent sonication. Ultrafine fraction did not agglomerate after freezing/thawing the sample. Both lower accumulation and ultrafine fractions were stable in cell culture media with fetal bovine serum, while high agglomeration occurred in media without fetal bovine serum as measured during 24 h.

Making up for Missing Pieces: SEM-EDS Gunshot Residue Analysis of Human Cranial Bone

This report outlines a case in which cranial gunshot trauma was suspected, but a large portion of the cranium was not recovered from the scene, so the precise nature and etiology of the fractures could not be determined with certainty. Scanning electron microscopy (SEM) coupled with energy dispersive x-ray spectroscopy (SEM-EDS) is widely accepted as a reliable method for detecting gunshot residue (GSR) on the hands of shooters and on fleshed remains, and experimental research has shown that the technique is applicable to skeletal remains. Therefore, SEM-EDS was utilized to analyze several cranial fragments and a control fragment from a thoracic vertebra for gunshot residue. The technique enables the examination of particle morphology and elemental composition of the inorganic compound. Barium, antimony, and lead were detected on four of the five cranial fragments, confirming the presence of gunshot residue. The fifth fragment had barium and lead, but no antimony. No trace elements were detected on the control fragment from the thoracic vertebra. SEM analysis of the bone surface revealed the presence of characteristic GSR spherical deposits on three of the fragments. The combined presence of signature trace elements and spherical surface deposits on the cranial fragments are consistent with the presence of gunshot residue. The cause of death was certified as disruptive head trauma, and given the circumstances of the case the manner of death was certified as homicide. The SEM-EDS analysis confirmed and supported the pathologist’s and anthropologist’s assessment of the circumstances surrounding the death. KEYWORDS: forensic anthropology, forensic science, gunshot wounds, skeletal trauma, gunshot residue, scanning electron microscopy, energy-dispersive x-ray spectroscopy

Anticancer, antibacterial and pollutant degradation potential of silver nanoparticles from Hyphaene thebaica

We present here the biosynthesis of AgNps from the aqueous extract of H. thebaica fruit, and monitored through UV-Vis spectrophotometer. The functional group were characterized through ATR-FTIR spectroscopy, the particle size, morphologies and elemental composition of the nanoparticles were investigated by using TEM, FESEM and EDS respectively. The anti-proliferation activity of the synthesized AgNps was carried out using MTT assay on human prostate (PC3), breast (MCF7) and liver (HepG2) cancer cell lines. The anti-proliferation assay showed that the AgNps were able to inhibit the proliferation of the cancer cell lines in a dose depending manner. The effect was found more pronounced on prostate (IC50 2.6 mg/mL) followed by breast (IC50 4.8 mg/mL) and then liver cancer cell lines (IC50 6.8 mg/mL). The prepared AgNps were found to inhibit 99% growth of both E. coli and S. aureus after 24 h of incubation. The nanoparticles were used for the degradation of 4-nitrophenol (4-NP) and Congo red dyes (CR), which efficiently degrade CR, but make complex formation with 4-NP. Therefore, the AgNps synthesized from the aqueous fruit extract of H. thebaica have potential application in pharmacology and waste water treatment.

Performance of a Mobile Star Screen to Improve Woodchip Quality of Forest Residues

Low harvesting costs and increasing demand for forest-derived biomass led to an increased use of full-tree (FT) harvesting in steep terrain areas in Austria. Logging residues, as a by-product of FT harvesting, present an easily accessible bioenergy resource, but high portions of fine particles and contaminants like earth particles and stones make them a complex and difficult fuel, as they affect storage capability, conversion efficiency, or emission rates adversely. The present research focuses on the productivity and performance of a star screen, which was used to remove fine and oversize particles from previously chipped, fresh Norway spruce (Picea abies (L.) Karst.) logging residue woodchips. Three screen settings, which differed in terms of different rotation speeds of the fine star elements (1861 rpm, 2239 rpm, 2624 rpm) were analyzed. Time studies of the star screen were carried out to estimate screening productivity and costs. Furthermore, 115 samples were collected from all material streams, which were assessed for particle size distribution, calorific value, ash content, and component and elemental composition. Average productivity was 20.6 tonnes (t) per productive system hour (PSH15), corresponding to screening costs of 9.02 €/t. The results indicated that the screening of chipped logging residues with a star screen influenced material characteristics of the medium fraction, as it decreased the ash content, the incidence of fine particles, and the nutrient content. The different screen settings had a noticeable influence on the quality characteristics of the screening products. An increase of the rotation speed of the fine stars reduced screening costs per unit of screened material in the medium fraction, but also lowered screening quality.

Study of Microbiological Synthesized TiO2 Nanomaterials

The evolution of science and technology has been shifted towards nano science and technology as the demand and application of the nano technology is growing very rapidly. With respect to this, metal oxide nano materials play very important role in various applications. Titanium dioxide is one of the most important metal oxide nano materials, which is being broadly investigated because of its unique hydrophobic nature, photo catalytic, electrical and optical properties. These nanoparticles are prepared by different physical methods,chemical methods and biological methods. This review article is focussed on various synthesis methods empha- sising on biological methods because of their wide range of techniques availabilities. Various characterisation techniques for biologically synthesised nanoparticles are discussed. The characterization techniques performed are XRD, FESEM, AFM, PSA, EDX, TG-DTA, FTIR and UV- Visible for the study of crystal structure, mor- phology & size, surface properties, average particle size, elemental compositions, thermal properties, bond analysis and optical properties respectively. Applications of these nano particles are described in briefly such as solar cells, sensors, device fabrication, self-cleaning and environmental. Keywords: Biological methods, meal oxides, nanotechnology, Ti02 nanoparticles, Ti02 nanoparticles applications, XRD.

Fly Ash Formation during Suspension Firing of Biomass: Effects of Residence Time and Fuel Type

The objective of this work was to generate comprehensive data on the formation of residual fly ash during the initial stages of suspension firing of biomass. Combustion experiments were carried out with pulverized biomass fuels (two straw fuels and two wood fuels), in an entrained flow reactor at 1200–1400 °C, simulating full-scale suspension firing of biomass. By the use of a movable, cooled, and quenched gas/particle sampling probe, samples were collected at different positions along the vertical axis in the reactor, corresponding to gas residence times ranging from 0.25 to 2.0 s. The collected particles were subjected to various analyses, including char burnout level, particle size distribution, elemental composition, and particle morphology and composition. Furthermore, the transient release, i.e., the vaporization of the flame-volatilized inorganic elements K, Cl, and S, from the burning fuel particles to the gas phase, has been quantified using two different calculation methods. The ash formation me...

Increasing dust fluxes on the northeastern Tibetan Plateau linked with the Little Ice Age and recent human activity since the 1950s

Arid and semi-arid areas in inner Asia contribute lots of mineral dust in the northern hemisphere, but dust flux evolution in the past is poorly constrained. Based on particle sizes and elemental compositions of a sediment core from Lake Qinghai on the northeastern Tibetan Plateau, dust fluxes during ∼1518–2011 A.D. were reconstructed based on 18–100 μm fractions of the lake sediment. The dust fluxes during the past ∼500 years ranged between 100 and 300 g/m2/yr, averaging 202 g/m2/yr, experiencing four stages: Stage 1 (∼1518–1590s), the flux was averaged 165 g/m2/yr, much lower than that in the Stage 2 (1590s–1730s, 254 g/m2/yr); similarly, an average flux of 169 g/m2/yr in the Stage 3 (1730s–1950s) was followed by an increased flux of 259 g/m2/yr in the Stage 4 (1950s–2011). During the first three stages the fluxes were dominated by natural dust activities in arid inner Asia, having a positive relation with wind intensity but a poor correlation with effective moisture (or precipitation) and temperature. The high dust flux in Stage 2 was due to relatively strong wind during the maximum Little Ice Age, whereas the remarkably high flux in 1950s–2011 was resulted from recent increasing human activities in northwestern China. The dust record not only documents past dust fluxes on the northeastern Tibetan Plateau but also reflects evolutions and mechanisms of dust activity/emission in inner Asia during the past ∼500 years.

Synthesis of Cu-CuO nanocomposite in microreactor and its application to photocatalytic degradation

The nanocomposite of Cu-CuO is successfully prepared via controlled oxidation of Cu nanoparticles synthesized by liquid-phase reduction in a microreactor. The particle's morphology, size, and elemental compositions have been investigated. Experimental results demonstrate that copper nanoparticles are spherical in shape, with good dispersion and narrow particle size distribution. The surface of Cu nanoparticles was oxidized to CuO, and the size of Cu-CuO composites crystallites was around 10 nm, consistent with the size of copper nanoparticles. The prepared Cu-CuO nanocomposite along with the presence of H2O2 exhibits excellent photocatalytic activity for degradation of methylene blue (MB) under UV irradiation. An overall degradation of 98.5% could be achieved with 10 mg of Cu-CuO nanocomposite along with 1 mL of H2O2, within duration of 50 min irradiation. The MB degradation kinetics was observed to follow first order.

Effect of calcinations on the structure and morphological properties of Ag and In co-doped ZnO nanoparticles

Nanoparticles of Zinc oxide (ZnO) are widely used in many fields serving as catalysts, wear resistance materials and advanced of applicable process. Pure and Indium-Silver co-doped ZnO nanoparticles are synthesized via Sol–gel method followed by calcinations at 400, 500 and 600 °C for 2 h. The influence of calcinations temperature on the particle size, the structural, morphological, Elemental composition, Chemical and optical properties were examined by X-ray diffraction, scanning electron microscope, energy dispersive X-ray absorption, fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and UV–Vis absorption spectrum. The average particle size of the synthesized ZnO nanoparticles is calculated using the Scherrer formula and is found to be less than 20 nm. These results also indicate that there is an improvement in the crystalline of ZnO nanoparticles with the increase in the calcination temperature.

Investigating the Influence of Transition Metal Composition on High-Voltage Cathodes Performance By Using Magnetic Susceptibility

High-voltage cathodes are indispensable to enable the high-energy-density batteries. This work demonstrates the effect of Ni/Mn composition on structure of pristine and cycled layered Li-Ni-Mn/Al-Co oxide (NMC and NCA) during high-voltage operation (4.75V vs. Li). Particle morphology and elemental composition of all material was investigated by using scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX) analysis. Among the various materials NMC622 had the best uniformity in particle size at ~10um while the other materials ranged from ~5-10um. X-ray diffraction (XRD) spectra of the as-obtained powders showed little variation in the structure of layered oxide with different transition metal ion compositions. Temperature dependent magnetic susceptibility results show that NMC622 (with 60% Ni) is layered with less magnetic ordering which was very similar to that of NCA811 (80% Ni) while NMC442 (40% Ni) showed strong magnetic ordering, which suggests exchange of strong magnetic interaction among transition metal ions in NMC442 material. The structural differences that were observed from magnetic susceptibility results were correlated with the electrochemical performance. The detailed pristine structure and structural evolution in layered oxides varying the Ni concentration in the light of magnetic susceptibility will be presented.

Mechanistic Study of Gas-Phase Controlled Synthesis of Copper Oxide-Based Hybrid Nanoparticle for CO Oxidation

We report a systematic study of gas-phase controlled synthesis of copper oxides-based hybrid nanoparticles for catalytic CO oxidation. The complementary physical, spectroscopic, and microscopic analyses were conducted to obtain a better understanding of the material properties, including particle size, crystallinity, elemental composition, and oxidation state. Results showed that the synthesized nanoparticles exhibited highly durable catalytic activity and stability, also the particle size, crystallite size, and chemical composition were tunable by choosing suitable chemical compositions of precursors and temperatures. The crystallite size of CuO influenced the reducibility of CuO by CO and the subsequent catalytic activity of CO oxidation. The hybridization process of CeO2 and CuO induces the formation of new active sites at the Cu–Ce–O interface, which enhances reproducibility of CuO and the catalytic activity. However, the reproducibility of CuO and catalytic activity were considerably decreased when C...

Editor's Highlight: Abrasion of Artificial Stones as a New Cause of an Ancient Disease. Physicochemical Features and Cellular Responses.

New outbursts of silicosis were recently reported among workers manufacturing an engineered material known as "artificial stone," composed by high percentages of quartz (up to 98%) agglomerated with pigments and polymeric resins. Dusts released by abrasion during artificial stone polishing were characterized for particle size, morphology, and elemental composition and studied for (1) ability to catalyze free radical generation in acellular tests, (2) membranolytic potential on human erythrocytes, (3) cytotoxic activity (lactate dehydrogenase release) on murine alveolar macrophages (MH-S) and human bronchial epithelial (BEAS-2B) cell lines, (4) induction of epithelial-mesenchymal transition (EMT) in BEAS-2B cells. Min-U-Sil 5 was used as reference quartz. Artificial stone dusts exhibited morphological features close to quartz, but contained larger amount of metal transition ions (mainly, Fe, Cu, and Ti), potentially responsible for the high reactivity in free radical generation observed. Opposite to Min-U-Sil 5, they were neither hemolytic nor cytotoxic on MH-S cells, a low cytotoxicity only being observed with BEAS-2B cells. The presence on the particle surface of residues of the resin accounts for this attenuated behavior, as hemolysis appeared and cytotoxicity increased after thermal degradation of the resin, when the free quartz surface was exposed. All dusts induced EMT with loss of E-cadherin expression and increased the expression of mesenchymal proteins (α-smooth muscle actin and vimentin). This may contribute to explain the development of fibrosis on workers exposed to artificial stone dusts.

Characterization of particle exposure in ferrochromium and stainless steel production

ABSTRACT This study describes workers’ exposure to fine and ultrafine particles in the production chain of ferrochromium and stainless steel during sintering, ferrochromium smelting, stainless steel melting, and hot and cold rolling operations. Workers’ personal exposure to inhalable dust was assessed using IOM sampler with a cellulose acetate filter (AAWP, diameter 25 mm; Millipore, Bedford, MA). Filter sampling methods were used to measure particle mass concentrations in fixed locations. Particle number concentrations and size distributions were examined using an SMPS+C sequential mobile particle sizer and counter (series 5.400, Grimm Aerosol Technik, Ainring, Germany), and a hand-held condensation particle counter (CPC, model 3007, TSI Incorporated, MN). The structure and elemental composition of particles were analyzed using TEM-EDXA (TEM: JEM-1220, JEOL, Tokyo, Japan; EDXA: Noran System Six, Thermo Fisher Scientific Inc., Madison,WI). Workers’ personal exposure to inhalable dust averaged 1.87, 1.40, 2.34, 0.30, and 0.17 mg m−3 in sintering plant, ferrochromium smelter, stainless steel melting shop, hot rolling mill, and the cold rolling mill, respectively. Particle number concentrations measured using SMPS+C varied from 58 × 103 to 662 × 103 cm−3 in the production areas, whereas concentrations measured using SMPS+C and CPC3007 in control rooms ranged from 24 × 103 to 243 × 103 cm−3 and 5.1 × 103 to 97 × 103 cm−3, respectively. The elemental composition and the structure of particles in different production phases varied. In the cold-rolling mill non-process particles were abundant. In other sites, chromium and iron originating from ore and recycled steel scrap were the most common elements in the particles studied. Particle mass concentrations were at the same level as that reported earlier. However, particle number measurements showed a high amount of ultrafine particles, especially in sintering, alloy smelting and melting, and tapping operations. Particle number concentration and size distribution measurements provide important information regarding exposure to ultrafine particles, which cannot be seen in particle mass measurements.