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Atmospheric nanoparticles (PM0.1 µm) are a major cause of environmental problems and also affect health risk. To control and reduce these problems, sources identification of atmospheric particulates is necessary. Combustion of bituminous coal and biomass including rubber wood, palm kernel, palm fiber, rice stubble, rice straw, maize residue, sugarcane leaves and sugarcane bagasse, which are considered as sources of air quality problems in many countries, was performed. Emissions of particle-bound chemical components including organic carbon (OC), elemental carbon (EC), water-soluble ions (NH

Transboundary haze from biomass burning is one of the most important air pollutions in Southeast Asia. The most recent serious haze episode occurred in 2015. Southern Thailand was affected by the haze during September to October when the particulate matter concentration hit a record high. We investigated physical and chemical characteristics of aerosols, including concentration and aerosol size distribution down to sub-micron sizes during haze episodes in 2013 and 2015 and, for reference, an insignificant haze period in 2017. The highest total suspended particulates and PM10 levels in Hat Yai city were 340.1 and 322.5 µg/m3. The mass fractions were nanoparticles (< 100 nm) 3.1%-14.8% and fine particles (< 1 µm) 54.6%-59.1%. Polycyclic aromatic hydrocarbon size distributions in haze periods peaked at 0.75 µm and the concentrations are 2-30 times higher than the normal period. High molecular weight (4-6 ring) PAHs during the haze episode contribute to about 56.7%-88.0% for nanoparticles. The average values of benzo(a)pyrene toxic equivalency quotient were 3.34±2.54ng/m3 in the 2015 haze period but only 0.89±0.17 ng/m3 in 2017. It is clear that particles smaller than 1 µm, were highly toxic. Nanoparticles contributed 19.4%-26.0% of total BaP-TEQ, whereas the mass fraction is 13.1%-14.8%. Thus the nanoparticles were more carcinogenic and can cause greater health effect than larger particles. The fraction of BaP-TEQ for nanoparticles during 2017 non-haze period was nearly the same, while the mass fraction was lower. This indicates that nanoparticles are the significant source of carcinogenic aerosols both during haze and non-haze periods.

Size-segregated ambient particles down to particles smaller than 0.1 μm (PM0.1) were collected during the year 2014–2015 using cascade air samplers with a PM0.1 stage, at two cities in Thailand, Bangkok and Chiang Mai. Their characteristics and seasonal behavior were evaluated based on the thermal/optical reflectance (IMPROVE_TOR) method. Diagnostic indices for their emission sources and the black carbon (BC) concentration were assessed using an aethalometer and related to the monthly emission inventory (EI) of particle-bound BC and organic carbon (OC) in order to investigate the contribution of agricultural activities and forest fires as well as agro-industries in Thailand. Monthly provincial EIs were evaluated based on the number of agricultural crops produced corresponding to field residue burning and the use of residues as fuel in agro-industries, and also on the number of hot spots from satellite images corresponding to the areas burned by forest fires. The ratio of char-EC/soot-EC describing the relative influence of biomass combustion to diesel emission was found to be in agreement with the EI of BC from biomass burning in the size range

Ribbed Smoked Sheet (RSS) is one of the leading primary rubber products and is used as a raw material for tire production. An emission inventory (EI) analysis was conducted for the production and transportation of RSS in Thailand following the Life Cycle Inventory (LCI) methodology in order to highlight improvements needed to render the processes more environmentally friendly. The air emission inventory focussed on CO2, NOx, SOx, particulate matters (PM) and particle-bound polycyclic aromatic hydrocarbons (PAHs) using available databases, reports and previously published papers. Data was also obtained from a small-scale RSS factory, known as a cooperative, in Songkhla province, Thailand. Upstream para-rubber industries start from RSS in Thailand. Instead, downstream industries operate under tire production in Japan. There are high exported of RSS from Thailand to tire production in Japan. The material flow during the production and export of the amount of RSS produced and transported and the distances travelled were investigated. The results suggest that the tire production in Japan contributes more than 80% of the CO2 and 90% of the SOx emissions arising during the period from latex tapping to tire production. Conversely, 60% of PM and more than 90% of the PAHs were released from the drying process involving the wood-fuel burning without any pollution control devices. These results indicate that the environmental load due to hazardous air pollutants such as PAHs and smoke particles is serious in Thailand and has to be reduced to achieve environmentally sustainable tire production.

This research aims to investigate the effects of irradiation energy and residence time of soft X-ray irradiation in the decomposition of sixteen polycyclic aromatic hydrocarbons (PAHs) in smoke particles emitted from the Para rubber wood burning. The burning process was carried out in a tube furnace and the soft X-ray radiation used had a wave length of 0.13-0.41 nm. The irradiated (IR) and non irradiated (N-IR) smoke particles were collected simultaneously using a 10-stage Andersen sampler equipped with an inertial-filter stage (ANIF), in order to determine the physicochemical characteristic of both IR and N-IR smoke particles, including particle size distribution and concentration, and particle-bound PAHs concentration. Results show that the nano-size smoke particles contained the highest amount of PAHs and of carcinogenic potency equivalent (BaP-TEQ). About 75% of PAH compounds on the total smoke particles were decomposed at the highest irradiation energy. Moreover, 4-6 ring PAHs in nanoparticles (

We examined particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), and carcinogenic potencies of benzo[a]pyrene equivalent (BaP eq ) emissions from an indirect injection (IDI-turbo) diesel engine fueled by commercial diesel (PB0) and palm oil blends with portions of 40 and 50 vol.% (PB40 and PB50). The engine was in operation over long-term test cycles. A four-stage cascade impactor air sampler was used to collect particles emitted from the engine. The PM and PAHs were predominantly fine particles ( eq were reduced as the fraction ratio of palm oil was increased because palm oil blends have a high amount of oxygen, which enhances combustion compared to PB0. Although PM, PAHs, and BaP eq emissions of PB50 were less than those of PB0 and PB40, PB50 is not an appropriate fuel for the long-term running of this engine.

In this study, as the first step in mitigating contamination by PM0.1, particles with diameters less than 0.1 μm, the current air pollution situation in Indonesia was investigated with respect to particulate matter (PM), especially regarding the status and characteristics of PM0.1. Air sampling in different size ranges down to PM0.1 was conducted at roadsides, at a school adjacent to a road, an industrial area and an area near a volcano in North Sumatera Province. Analyses were conducted for carbonous components (OC, EC, TC, WSOC and WISOC), and ions including oxalate in the PM0.1 fraction. We identified PM2.5 and PM10 mass concentrations in the area of the city that exceeded WHO guidelines. From the chemical components in the PM0.1 fraction, we found that WISOC, NO3− and soot-EC were the most common components, suggesting that local traffic is a contributor and another group consisting of K+, SO42− and WSOC suggesting the occurrence of biomass burning related to local industrial and rural sources.

In this study, size-fractionated particulate matters (PM) down to ultrafine (PM0.1) particles were collected using a cascade air sampler with a PM0.1 stage, in Hat Yai city, Songkhla province, southern Thailand during the year 2018. The particle-bound carbonaceous aerosols (CA) as elemental carbon (EC) and organic carbon (OC) were quantified with the thermal/optical reflectance method following the IMPROVE_TOR protocol. The concentrations of different temperature carbon fractions (OC1-OC4, EC1-EC3 and PyO) in the size-fractionated PM were evaluated to discern OC and EC correlations as well as those between char-EC and soot-EC. The results showed that biomass burning, motor vehicle, and secondary organic aerosols (SOC) all contributed to the size-fractionated PM. The OC/EC ratios ranged from 2.90 to 4.30 over the year, with the ratios of PM2.5-10 being the highest, except during the open biomass burning period. The concentration of CA was found to increase during the pre-monsoon season and had its peak value in the PM0.5-1.0 fraction. The long-range transport of PMs from Indonesia, southwest of Thailand toward southern Thailand became more obvious during the pre-monsoon season. Transported plumes from biomass burning in Indonesia may increase the concentration of OC and EC both in the fine (PM0.5-1.0 and PM1.0-2.5) and coarse (PM2.5-10 and PM>10) fractions. The OC fraction in PM0.1 was also shown to be significantly affected by the transported plumes during the pre-monsoon season. Good OC and EC correlations (R2 = 0.824–0.915) in the fine particle fractions indicated that they had common sources such as fossil fuel combustion. However, the lower and moderate correlations (R2 = 0.093–0.678) among the coarser particles suggesting that they have a more complex pattern of emission sources during the dry and monsoon seasons. This indicates the importance of focusing emission control strategies on different PM particle sizes in southern Thailand.

Size-resolved aerosols were continuously collected by a Nano Sampler for 13 days at an urban site in Beijing during winter 2012 to measure the chemical composition of ambient aerosol particles. Data collected by the Nano Sampler and an ACSM (Aerodyne Aerosol Chemical Speciation Monitor) were compared. Between the data sets, similar trends and strong correlations were observed, demonstrating the validity of the Nano Sampler. PM10 and PM2.5 concentrations during the measurement were 150.5 ± 96.0 μg/m3 (mean ± standard variation) and 106.9 ± 71.6 μg/m3, respectively. The PM2.5/PM10 ratio was 0.70 ± 0.10, indicating that PM2.5 dominated PM10. The aerosol size distributions showed that three size bins of 0.5–1, 1–2.5 and 2.5–10 μm contributed 21.8%, 23.3% and 26.0% to the total mass concentration (TMC), respectively. OM (organic matter) and SIA (secondary ionic aerosol, mainly SO42 −, NO3− and NH4+) were major components of PM2.5. Secondary compounds (SIA and secondary organic carbon) accounted for half of TMC (about 49.8%) in PM2.5, and suggested that secondary aerosols significantly contributed to the serious particulate matter pollution observed in winter. Coal burning, biomass combustion, vehicle emissions and SIA were found to be the main sources of PM2.5. Mass concentrations of water-soluble ions and undetected materials, as well as their fractions in TMC, strikingly increased with deteriorating particle pollution conditions, while OM and EC (elemental carbon) exhibited different variations, with mass concentrations slightly increasing but fractions in TMC decreasing.

Mixed crude palm oil (MCPO), the mixture of palm fiber oil and palm kernel oil, has become of great interest as a renewable energy source. It can be easily extracted from whole dried palm fruits. In the present work, the degummed, deacidified MCPO was blended in petroleum diesel at portions of 30% and 40% by volume and then tested in agricultural diesel engines for long-term usage. The particulates from the exhaust of the engines were collected every 500 hr using a four-stage cascade air sampler. The 50% cut-off aerodynamic diameters for the first three stages were 10, 2.5 and 1 microm, while the last stage collected all particles smaller than 1 microm. Sixteen particle bounded polycyclic aromatic hydrocarbons (PAHs) were analyzed using a high performance liquid chromatography. The results indicated that the size distribution of particulate matter was in the accumulation mode and the pattern of total PAHs associated with fine-particles (1 microm) showed a dominance of larger molecular weight PAHs (4-6 aromatic rings), especially pyrene. The mass median diameter, PM and total PAH concentrations decreased when increasing the palm oil content, but increased when the running hours of the engine were increased. In addition, Commercial petroleum diesel (PB0) gave the highest value of carcinogenic potency equivalent (BaP(eq)) for all particle size ranges. As the palm oil was increased, the BaP(eq) decreased gradually. Therefore the degummed-deacidified MCPO blends are recommended for diesel substitute.

The carbonaceous and ionic components of atmospheric ultrafine particles (UFPs; Dp

Polyphenylene sulfide (PPS) non-woven fabrics are often used at high temperatures for bag filters in incinerating plants. Even though they degrade in the presence of acid gases, there has been not much information on the degradation of mechanical properties of PPS in nitric oxide (NO). At 200°C, which is generally the highest operational temperature of bag filters, PPS fabrics gradually lose their elongation even if the modulus is barely unaffected. On the other hand, at 250°C, which is near its melting temperature of 285°C, the modulus increases while the elongation decreases. Contrary to our first guess, PPS does not soften near its melting temperature and becomes even more rigid. Our hypothesis then becomes that crosslinking and branching dominate around 250°C, leading to the embrittlement of PPS bag-filter materials and severe strength loss. Therefore, it is our recommendation that the operational temperature of PPS bag filters should always be below 200°C and the NO concentration should be far below 1000 p.p.m., at which point chemical degradation occurs severely.

Polyphenylene sulfide (PPS) is known as a material resistant to high temperature and chemicals; however, there are arguments on the durability of PPS non-woven fabrics to chemicals, such as nitric acid (HNO3), sulfuric acid (H2SO4), and hydrochloric acid (HCl). Therefore, this work aims at investigating the degradation of PPS non-woven fabrics in HNO3, H2SO4 and HCl, and at confirming acid durability of PPS non-woven fabrics. In addition, this paper also studies the interaction among these three acids by measuring the retention of strength in binary or tertiary mixtures of these three acids. A discussion has been made on the acceleration/retardation of PPS degradation by the interactive effects, and also on the chemistry related to the degradation by these acids. Furthermore, there is a linear relationship between the nitric acid concentration and the proportion of carbon in the remaining PPS structures after 100 h of acid exposure. Also, this proportion of carbon is a good indicator of the retained strength in PPS fabrics.

In incineration plants, nitric oxide (NO) and oxygen (O 2 ) are the two major gaseous components, which degrade the mechanical properties of bag-filter media. Based on the experimental results of mass, dimension, morphology, crystallinity, fiber diameter, fiber orientation and fabric strength, changes in mechanical properties of polyphenylene sulfide (PPS) needled fabrics are related to two phenomena, i.e. the crystallization and the degradation of amorphous regions and some parts of crystalline regions. Both processes affect the fabric strength, competing with each other. The relation between strength and crystallinity is divided into two phases: (1) strength is dominated by crystallinity, and (2) strength is dependent on the defects in amorphous regions and some parts of crystalline regions. An increase in NO concentration has a potential to increase the deterioration rates of amorphous and crystalline phases but the crystallization process is unaffected. An increase in O 2 concentration leads to enhancement of both crystallization and deterioration.

The dust-releasing behavior from a ceramic candle filter, which is a key technology of the hot gas cleaning system in advanced coal power generation processes such as pressurized fluidized bed combustion and integrated gasification combined cycle, is discussed based on the observation of the dust-releasing process using a high-speed video camera and the measurement of time change of pressure inside the filter. Time changes of dust-released area and geometrical characteristics and motion of released dust cake fragments were investigated by analyzing photo images from the video camera, compared with the time change and distribution of pressure inside the filter. In order to discuss the influence of porosity of the dust layer, a consolidated dust layer was prepared by clean air filtration at an elevated filtration velocity after the dust filtration. The dust-releasing process was found to be a multi-mode process, i.e. release occurred in a short time after the injection of cleaning air, followed by one or two intermittent releases afterwards. The amount of dust released by the first strike increased with tank pressure. The dust-releasing behavior was sensitive to the cake porosity: the mean size and perimeter of cake fragments increased with porosity and tank pressure for the consolidated dust layer. The initial radial velocity of cake fragment released just after the first strike increased with tank pressure and was almost independent of the filter location.

Monodispersed fine silica spheres were sedimented in KCl solution under an electrophoretic force applied in the gravitational or antigravitational direction. Effects of particle size, particle volume fraction, electrolyte concentration and applied field intensity were experimentally investigated. A Fast Fourier Transform analysis was conducted for the sediment surface and the degree of ordering of particles was evaluated. Two different conditions were found to affect the particle ordering, one related to the kinetic energy of the settling particle and the other related to the agglomeration.

Shape separation of elongated particles is conducted by a rotating horizontal sieve drum with equal circularholes of diameter 0.4 mm, through which all particles placed in the interior can flow out. The drum is 100 mm in diameter and 500 mm in length. The residence time of particles in the drum relates to the particle shape. Hence particles can be separated according to the aspect ratio. The residence time of particles is measured and related to the particle shape, the initial hold-up and the rotational frequency of drum. The particle flow through the drum is modeled to discuss the influence of the operating conditions on the residence time. It is found that the residence time increases with the aspect ratio and hold-up. The residence time distribution of the mixture of multi-shaped particles is made obtainable by a modified perfect mixing model. The particles are successfully separated according to the aspect ratio and the separation efficiency is discussed.

The separation of particles according to shape is necessary for improving the quality of powder products. The shape of a particle significantly affects

The shape separator previously reported consists of a rotating tilted cylinder with a row of blades. It can separate various shapes of granular materials according to the critical rotational frequency. In the present study, a test sample is precisely classified into particle groups according to the critical rotational frequency and the shape characterization is conducted for individual particles of each group by measuring their shapes from orthogonal three directions. It is found that the test sample is so precisely classified that one cannot distinguish the particle groups from each other by average shape descriptors; Mahalanobis' distance in the discriminant analysis is useful for this purpose. The critical rotational frequency is more sensitive to the multi-variate shape descriptors than the single-variate ones in the case of the geometric shape.

The residence time of particles in a rotating tilted cylinder was investigated experimentally for various particle shapes and concentrations. In the single particle movement, the residence time relates to to tan ω0, where ω0 is the average angle in a horizontal cylinder up to which the particle is lifted by the rotation of the cylinder. The motion of the single particle is modeled and an investigation is made into the effect of the particle concentration on the residence time. The residence time can be expressed in terms of tan ω0 and the rotational frequency of the cylinder. The boundary between the uniform acceleration motion and the uniform velocity motion is found to exist at tan ω0 ≃ 0.25. A similar boundary also exists in the case of multiparticle flows. The residence time of particles increases exponentially with respect to the particle hold-up or the average area fraction of particles in the multi-particle flow. Particles with larger contact area on the cylinder wall seem insensitive to the interaction among themselves.

Using a rotating cylinder with blades previously reported for the batch mode operation, binary mixtures of spherical and non-spherical particles are classified continuously according to shape. Newton's separation efficiency is calculated for various operational conditions and the optimum conditions are found for the continuous shape separation. The performances of the classifier run in batch and continuous modes are compared with each other and the superiority of the continuous operation to the batch mode is shown for the rate of shape separation.