A review on management practices, environmental impacts, and human exposure risks related to electrical and electronic waste in Vietnam: findings from case studies in informal e-waste recycling areas.

Electrical and electronic waste (e-waste) has become a global concern, especially in developing countries. In this review, we conducted a literature survey of e-waste management practices, processing activities, and adverse effects in Vietnam, an emerging country in Southeast Asia, by gathering data from peer-reviewed articles published between 2009 and 2021. This is the first review paper to comprehensively discuss management and research aspects regarding e-waste in an Asian developing country. Due to the lack of an effective management and recycling system, a certain portion of Vietnamese e-waste has been processed by informal sectors without appropriate recycling and pollution control technology, resulting in localized contamination and human exposure to toxic chemicals. Primitive processing activities, such as manual dismantling, open burning, and plastic recycling, have been identified as important contributors to the environmental emission and human exposure to toxic elements (notably As, Mn, Ni, Pb, Zn) and organic pollutants like flame retardants, PAHs, PCBs, and dioxin-related compounds. Informal e-waste processing from these small-scale workshops can release pollutants at similar levels compared to large-scale facilities in developed countries. This fact suggests an urgent need to develop management best practices for e-waste in Vietnam as well as other emerging and developing countries, in order to increase recycling efficiency and minimize their adverse impacts on environmental and human health.

Emission of Dioxin-like Compounds and Flame Retardants from Commercial Facilities Handling Deca-BDE and Their Downstream Sewage Treatment Plants.

Commercial mixtures of decabromodiphenyl ether (deca-BDE), a brominated flame retardant, contain not only polybrominated diphenyl ethers (PBDEs, mainly BDE-209) as the main component but also dioxin-like compounds (DLCs) such as polybrominated dibenzofurans (PBDFs). Deca-BDE handling facilities (DHFs) and sewage treatment plants receiving effluent from DHFs are point sources of DLC and flame retardant (FR) pollution. Here, we examined their emission in Japan. For DHF effluents, DLCs detected by the dioxin-responsive chemically activated luciferase expression (DR-CALUX) assay were 1.3-890 pg TCDD-EQ/L (median 46 pg TCDD-EQ/L), while PBDEs and other FRs were <2.0-110,000 ng/L (610 ng/L) and 150-4,800,000 ng/L (41,000 ng/L). Risk quotients based on predicted no-effect concentrations suggested that DLCs, decabromodiphenyl ethane (DBDPE), tris(2,3-dibromopropyl) isocyanurate (TDBP-TAZTO), and bisphenol A bis(diphenyl phosphate) (BPA-BDPP) present significant risks for aquatic organisms. The concentrations of PBDFs, which are impurities in deca-BDE, were expected to decrease with the inclusion of deca-BDE in the Stockholm Convention list of persistent organic pollutants (May 2017). However, DLCs other than PBDFs and alternative FRs such as DBDPE, TDBP-TAZTO, and BPA-BDPP are likely still discharged. Additional findings indicate that strong (e.g., DLCs, DBDPE, and BPA-BDPP), but not weak (e.g., TDBP-TAZTO), hydrophobic compounds are sufficiently removed by current wastewater treatment processes in Japan.

Gastrointestinal bleeding increases the risk of subsequent cardiovascular events in patients with acute cardiovascular diseases requiring intensive care.

Gastrointestinal (GI) bleeding worsens the outcomes of critically ill patients in the intensive care unit (ICU). Owing to a lack of corresponding data, we aimed to investigate whether GI bleeding during cardiovascular-ICU (C-ICU) admission in acute cardiovascular (CV) disease patients is a risk factor for subsequent CV events. Totally, 492 consecutive C-ICU patients (40.9% acute coronary syndrome, 22.8% heart failure) were grouped into GI bleeding (n = 27; 12 upper GI and 15 lower GI) and non-GI bleeding (n = 465) groups. Thirty-nine patients died or developed CV events during hospitalization, and 453 were followed up from the date of C-ICU discharge to evaluate subsequent major adverse CV events. The GI bleeding group had a higher Acute Physiology and Chronic Health Evaluation II score (20.2 ± 8.2 vs. 15.1 ± 6.8, p < 0.001), higher frequency of mechanical ventilator use (29.6% vs. 13.1%, p = 0.039), and longer C-ICU admission duration (8 [5-16] days vs. 5 [3-8] days, p < 0.001) than the non-GI bleeding group. The in-hospital mortality rate did not differ between the groups. Of those who were followed-up, CV events after C-ICU discharge were identified in 34.6% and 14.3% of patients in the GI and non-GI bleeding groups, respectively, during a median follow-up period of 228 days (log rank, p < 0.001). GI bleeding was an independent risk factor for subsequent CV events (adjusted hazard ratio: 2.23, 95% confidence interval: 1.06-4.71; p = 0.035). GI bleeding during C-ICU admission was independently associated with subsequent CV events in such settings.

Recycling Potentials of Precious Metals from End-of-Life Vehicle Parts by Selective Dismantling.

Recycling of some minor but essential scarce metals used in vehicles may serve as an important strategy to strengthen sustainable management of natural resources. Accordingly, this study focused on five precious metals (PMs): Au, Ag, Pt, Pd, and Rh, in both end-of-life conventional and next-generation vehicles. To explore their recycling potentials in Japan, we developed substance flow and scenario analyses based on estimations of PM contents per end-of-life vehicle (ELV) and ELV generations. The study predicts that in Japan, from 2015 to 2040, the content of PMs per ELV will range from 2 to 6 g, and the annual amount of PMs in ELVs will remain largely stable, at 14-15 t, but the proportions of PMs utilized in different vehicles, parts, and components will gradually change; in particular, increased proportions will occur in the printed wiring boards (PWBs) of next-generation vehicles. The results also show that, in Japan, totals of 33-53% of PMs in ELVs were recycled in 2015, and that by selective dismantling of PWBs and heating wires in the rear windows of ELVs, the recycling potentials of PMs could be optimally increased to a maximum of 62-83% by 2040.

Analysis of mismanaged plastic waste in Samoa to suggest proper waste management in Pacific island countries.

Pacific island countries are facing critical challenges in managing the growing amount of increasingly diverse wastes because of changing lifestyles and the concentration of populations in urban areas. Although marine plastic waste is an issue in the Pacific region, there have been almost no studies of the estimation and impacts of ocean plastic waste, and measures to control such waste, in these countries. Here, first we conducted a questionnaire survey about consumption and disposal of plastic products at households in Samoa as one of the examples of Pacific island countries to grasp the flow of plastic materials and awareness or behaviour for plastic waste. Then we quantified ocean plastic waste and discussed the effective and needed countermeasures in Pacific island countries. The total amount of mismanaged plastic waste was estimated to be 327,000 or 156,000 t y-1 (depending on the scenario) in Pacific island countries. The regional Pacific island countries contribution to the global total mismanaged plastic waste was estimated to range from 1.3% to 2.7%. The amount of mismanaged plastic waste per capita in some Pacific island countries, such as Solomon Islands and Micronesia, was also ranked highly globally. The main reasons seem to be that waste collection rates are relatively low in rural areas and rates of plastic waste generation are high. To implement solutions, including improving municipal solid waste collection, reducing plastic waste, improving the collection and recycling of plastics, and the integration of a number of policies is essential.

Correlation between Atmospheric Boundary Layer Height and Polybrominated Diphenyl Ether Concentrations in Air.

In this study, we aim to determine the correlation between the height of the atmospheric boundary layer (ABL) and the concentrations of polybrominated diphenyl ether (PBDE) congeners, in an effort to improve comprehension of the atmospheric behavior of PBDEs. We used the PBDE data in air (n = 298), which were measured by the Japan Ministry of Environment (JMOE) at 50 sites across Japan during the period 2009-2012. The height of the ABL, which directly affects the PBDE concentrations in the near-surface air, was estimated by employing data retrieved from the Japanese global reanalysis (JRA-55) database, using the parcel and Richardson number method. The ABL has shown a strong inverse relationship with BDE-47 and BDE-99 (p < 0.01). In contrast, there was less correlation between BDE-209 and the ABL (p = 0.258). These differing behaviors could be explained by differences in particle size distribution of PBDEs, where BDE-47 and BDE-99 are associated with gas phases and fine particles and BDE-209 is associated with coarse particles. To our knowledge, this paper represents the first large-scale analysis of correlations between the ABL and the concentrations of PBDEs in the air.

Contribution of hand and foot force to take-off velocity for the kick-start in competitive swimming.

This study examines the hand and foot reaction force recorded independently while performing the kick-start technique. Eleven male competitive swimmers performed three trials for the kick-start with maximum effort. Three force platforms (main block, backplate and handgrip) were used to measure reaction forces during starting motion. Force impulses from the hands, front foot and rearfoot were calculated via time integration. During the kick-start, the vertical impulse from the front foot was significantly higher than that from the rearfoot and the horizontal impulse from the rearfoot was significantly higher than that from the front foot. The force impulse from the front foot was dominant for generating vertical take-off velocity and the force impulse from the rearfoot was dominant for horizontal take-off velocity. The kick-start's shorter block time in comparison to prior measurements of the grab start was explained by the development of horizontal reaction force from the hands and the rearfoot at the beginning of the starting motion.

Greenhouse gas emissions from the treatment of household plastic containers and packaging: replacement with biomass-based materials.

The purpose of this study was to quantify the life-cycle greenhouse gas (GHG) emissions reduction that could be achieved by replacement of fossil-derived materials with biodegradable, biomass-based materials for household plastic containers and packaging, considering a variety of their treatment options. The biomass-based materials were 100% polylactide or a combination of polybutylene succinate adipate and polylactide. A scenario analysis was conducted considering alternative recycling methods. Five scenarios were considered: two for existing fossil-derived materials (the current approach in Japan) and the three for biomass-based materials. Production and waste disposal of 1 m(3) of plastic containers and packaging from households was defined as the functional unit. The results showed that replacement of fossil-derived materials with biomass-based materials could reduce life-cycle GHG emissions by 14-20%. Source separation and recycling should be promoted. When the separate collection ratio reached 100%, replacement with biomass-based materials could potentially reduce GHG emissions by 31.9%. Food containers are a priority for replacement, because they alone could reduce GHG emissions by 10%. A recycling system for biomass-based plastics must be carefully designed, considering aspects such as the transition period from fossil-derived plastics to biomass-based plastics.

Similarities in the endocrine-disrupting potencies of indoor dust and flame retardants by using human osteosarcoma (U2OS) cell-based reporter gene assays.

Indoor dust is a sink for many kinds of pollutants, including flame retardants (FRs), plasticizers, and their contaminants and degradation products. These pollutants can be migrated to indoor dust from household items such as televisions and computers. To reveal high-priority end points of and contaminant candidates in indoor dust, using CALUX reporter gene assays based on human osteosarcoma (U2OS) cell lines, we evaluated and characterized the endocrine-disrupting potencies of crude extracts of indoor dust collected from Japan (n = 8), the United States (n = 21), Vietnam (n = 10), the Philippines (n = 17), and Indonesia (n = 10) and for 23 selected FRs. The CALUX reporter gene assays used were specific for compounds interacting with the human androgen receptor (AR), estrogen receptor α (ERα), progesterone receptor (PR), glucocorticoid receptor (GR), and peroxisome proliferator-activated receptor γ2 (PPARγ2). Indoor dust extracts were agonistic to ERα, GR, and PPARγ2 and antagonistic against AR, PR, GR, and PPARγ2. In comparison, a majority of FRs was agonistic to ERα and PPARγ2 only, and some FRs demonstrated receptor-specific antagonism against all tested nuclear receptors. Hierarchical clustering clearly indicated that agonism of ERα and antagonism of AR and PR were common, frequently detected end points for indoor dust and tested FRs. Given our previous results regarding the concentrations of FRs in indoor dust and in light of our current results, candidate contributors to these effects include not only internationally controlled brominated FRs but also alternatives such as some phosphorus-containing FRs. In the context of indoor pollution, high-frequency effects of FRs such as agonism of ERα and antagonism of AR and PR are candidate high-priority end points for further investigation.

Underwater flutter kicking causes deceleration in start and turn segments of front crawl.

This study investigated the deceleration effect of flutter kicking after dolphin kicking before commencing the stroke at swimmer's emersion. Eight male competitive swimmers (age 19.6 ± 1.2 years; Fédération Internationale de Natation points 733.6 ± 57.5) performed 15 m front crawl sprints from wall push-off three times in a row, with two types of underwater kicks [dolphin kick only (dolphin condition) and dolphin kick followed by flutter kick (dolphin-flutter condition)]. Sprint bouts were divided into four phases. Phases 1 and 2 were defined, respectively, as the fourth and fifth dolphin kicks. Phase 3 was defined as the first stroke (dolphin condition) and six beats of the flutter kicking (dolphin-flutter condition). Phase 4 was defined as the second stroke (dolphin condition) and the first stroke (dolphin-flutter condition). Two-way repeated measured analysis of variance on mean swimming velocities demonstrated an interaction of condition and phase (p < 0.001) and a simple main effect (p < 0.001) at Phase 3. These results indicated greater deceleration due to adding the flutter kick after the dolphin kick before commencing the stroke. Swimmers should use only the underwater dolphin kick before commencing the front crawl in start and turn segments.

Factors affecting multiple persistent organic pollutant concentrations in the air above Japan: A panel data analysis.

Numerous reports have elucidated different statistical approaches to identify temporal trends in atmospheric persistent organic pollutant (POP) time series. However, the correlation of industrial activity with concentrations of atmospheric POPs in Japan has not yet been determined. Herein, a panel data analysis of a 16-year monitoring program (2003-2018) conducted by the Japanese Ministry of Environment was used to investigate a range of POPs in the atmosphere above Japan. This work focuses on polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), polybrominated diphenyl ethers (PBDEs), hexachlorobenzene (HCB), and pentachlorobenzene (PeCBz) collected each year at 53 sites across Japan. The panel analysis revealed that PCB, PCN, and PBDE concentrations were influenced by a combination of factors including year, industrial activity (municipal and industrial waste incinerators, cement kilns, steel industry, and secondary zinc production), population, temperature, and atmospheric boundary layer. However, HCB and PeCBz were not significantly affected by these factors. Industrial activity showed stronger positive correlations with all homologues of PCBs, PCNs, and PBDEs as compared to those demonstrated by population. Significant decreasing trends were identified for the atmospheric ∑PBDEs (half-life t1/2 = 9.4 years), ∑PCNs (t1/2 = 8.9 years), and ∑PCBs (t1/2 = 13.5 years) concentrations, while HCB and PeCBz showed slightly increasing or steady levels. As a statistical tool, panel data analysis can contribute to the assessment of spatial and temporal trends of POPs at a national scale, while elucidating different behavioral responses to numerous environmental variables.

Kinetics of four limb joints during kick-start motion in competitive swimming.

The kick-start technique in competitive swimming generates a force acting on the starting platform owing to gravity, muscle contraction and resulting joint torque. To understand optimal body movement on the starting platform for maximising take-off velocity, it is necessary to investigate the joint torque in relation to the joint's rotation effects. Joint torques were calculated by inverse dynamics using kinetic and kinematic data. A one-way ANOVA showed significantly greater extensional torque for shoulders than for elbows or wrists, and for hips than for knees or ankles. The results indicated that the force of the hands was mainly influenced by extension torque at the shoulder joint. Hip joint extension torque on the front side lower limb (FSLL) was mainly used for supporting the body weight until hands off. After hands off, the front-foot force originated mainly by increases in ankle joint plantar flexion and knee joint extension torque on the FSLL. Rear side lower limb torque increases in the hip, knee and ankle joints provided the rear-foot force. This investigation clarified the magnitudes and functions of each joint torque acting on the extremities during the kick-start, providing practical information for improving starting performance.

Clinical Characteristics, Achievement of Secondary Prevention Goals, and Outcomes of Patients with Recurrent Acute Coronary Syndrome.

BACKGROUND: Because development of acute coronary syndrome (ACS) worsens the prognosis of patients with coronary artery disease, preventing recurrent ACS is crucial. However, the degree to which secondary prevention treatment goals are achieved in patients with recurrent ACS is unknown. METHODS: 214 consecutive ACS patients were classified as having First ACS (n=182) or Recurrent ACS (n=32), and the clinical characteristics of these groups were compared. Fifteen patients died or developed cardiovascular (CV) events during hospitalization, and the remaining 199 patients were followed from the date of hospital discharge to evaluate subsequent CV events. RESULTS: Patients in the Recurrent ACS group were older than those in the First ACS group (76.8±10.8 years vs 68.8±13.4 years, p=0.002) and had a higher rate of diabetes mellitus (DM) (65.6% vs 36.8%, p=0.003). The rate of achieving a low-density lipoprotein cholesterol (LDL-C) level of <70 mg/dL in the Recurrent ACS group was only 28.1%, even though 68.8% of these patients were taking statins. An HbA1c level of <7.0% was achieved in 66.7% of patients with recurrent ACS who had been diagnosed with DM. Overall, 12.5% of patients with recurrent ACS had received optimal treatment for secondary prevention. CV events after hospital discharge were noted in 37.9% of the Recurrent ACS group and 21.2% of the First ACS group (log-rank test: p=0.004). However, recurrent ACS was not an independent risk factor for CV events (adjusted hazard ratio: 2.09, 95% confidence interval: 0.95 to 4.63, p=0.068). CONCLUSION: Optimal treatment for secondary prevention was not achieved in some patients with recurrent ACS, and achievement of the guideline-recommended LDL-C goal for secondary prevention was especially low in this population.

Use of comprehensive target analysis for determination of contaminants of emerging concern in a sediment core collected from Beppu Bay, Japan.

In recent years, concern about the release of anthropogenic organic micropollutants referred to as contaminants of emerging concern (CECs) has been growing. The objective of this study was to find potential CECs by means of an analytical screening method referred to as comprehensive target analysis with an automated identification and quantification system (CTA-AIQS), which uses gas and liquid chromatography combined with mass spectrometry (GC-MS and LC-QTOF-MS). We used CTA-AIQS to analyze samples from a sediment core collected in Beppu Bay, Japan. With this method, we detected 80 compounds in the samples and CTA-AIQA could work to useful tool to find CECs in environmental media. Among the detected chemicals, three PAHs (anthracene, chrysene, and fluoranthene) and tris(isopropylphenyl)phosphate (TIPPP) isomers were found to increase in concentration with decreasing sediment depth. We quantified TIPPP isomers in the samples by means of targeted analysis using LC-MS/MS for confirmation. The concentration profiles, combined with previous reports indicating persistent, bioaccumulative, and toxic properties, suggest that these chemicals can be categorized as potential CECs in marine environments.

Dioxin-like activity in Japanese indoor dusts evaluated by means of in vitro bioassay and instrumental analysis: brominated dibenzofurans are an important contributor.

In our previous study, we demonstrated that dioxin-like activity in sulfuric-acid-treated extracts of Japanese indoor dust was higher than the activity in contaminated sediments. In the current study, we used high-performance liquid chromatography (HPLC) fractionation in combination with the dioxin-responsive chemical-activated luciferase gene expression (DR-CALUX) assay and gas chromatography-high-resolution mass spectrometry (GC-HRMS) to quantitatively evaluate dioxin-like compounds in indoor dusts. Selected four sulfuric-acid-treated extracts of indoor dusts were fractionated into seven fractions by means of HPLC with a nitrophenylpropylsilica column, and the activity in the first fraction of each extract was much higher than the activities in the other fractions. Therefore, each of the first fractions was further fractionated into 90 fractions by HPLC with an octadecylsilica column, and all the fractions were analyzed by means of the DR-CALUX assay. On the basis of elution characteristics, the active compounds in the fractions showing high activity were determined to be polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), coplanar polychlorinated biphenyls (Co-PCBs), and polychlorinated naphthalenes (PCNs), or supposed to be polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs). These compounds in the 33 dusts extracts were quantified by means of GC-HRMS, and their median-based contributions of the theoretical CALUX-TEQs [2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-tetraCDD) equivalent] chemically calculated for PBDFs, PCDDs, PCDFs, non-ortho Co-PCBs, PCNs, and mono-ortho Co-PCBs to the experimental values (38-1400 pg/g, median 160 pg/g) were 17%, 14%, 8.8%, 0.98%, 0.10%, and 0.019%, respectively. Our results indicate that PBDFs, which are not internationally regulated dioxins, were important contributors to dioxin-like activity in Japanese dust and that further analysis of PBDFs in indoor dust is required so that the risk of exposure to these compounds via dust can be assessed.

Screening of dioxin-like compounds in bio-composts and their materials: chemical analysis and fractionation-directed evaluation of AhR ligand activities using an in vitro bioassay.

Application of the dioxin responsive-chemical activated luciferase gene expression (DR-CALUX) bioassay to three compost products (kitchen garbage compost, treated sludge compost, and poultry manure compost) and their organic waste materials was performed for the screening of dioxin-like compounds. Phased sample preparation was conducted for the bioassay to yield separate crude, acid-stable, and carbon column fractions. Chemical analyses were also conducted for polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polyaromatic hydrocarbons (PAHs). Their determined WHO-PCDD/PCDF/dl-PCB-TEQ values were compared to the DR-CALUX results expressed as CALUX-TEQ to ascertain their contributions to overall activity. Overall all three compost products were polluted to a low level by persistent PCDD/PCDF/dl-PCBs in a few pg/g WHO-TEQ concentration range. The organic crude fraction showed non-persistent CALUX-TEQ values 2-4 orders of magnitude higher than those of WHO-TEQ. For the acid-resistant fractions of all samples, persistent CALUX-TEQ values were 1-8-fold higher than WHO-PCDD/PCDF/dl-PCB-TEQ values. Both TEQs correlated well for this fraction, which confirms the availability of CALUX for estimation of the actual WHO-TEQ level of the samples using reflux method with 44% sulfuric acid/silica gel, although the compost and material samples examined in this study contained much lower levels of WHO-TEQ: less than 1 pg/g in almost all cases. Additional carbon column treatment enhanced the potency and efficacy of CALUX activity in the three compost samples, which showed 1.6-4.4 times higher values of CALUX-TEQ than those obtained for the acid-resistant fraction. Although further DR-CALUX data collection for compost samples will be necessary, DR-CALUX is useful as a rapid screening method for monitoring dioxin-like compounds in compost.

A new likelihood approach to autonomous multiple model estimation.

This paper presents an autonomous multiple model (AMM) estimation algorithm for hybrid systems with sudden changes in their parameters. Estimates of Kalman filters (KFs) that are tuned and employed for different system modes are merged based on a newly defined likelihood function without any necessity for filter interaction. The proposed likelihood function is composed of two measures, the filter agility measure and the steady-state error measure. These measures are derived based on filter adaptation rules. The numerical results show that the proposed algorithm, so called Competing AMM (CAMM), guarantees both steady-state estimation accuracy and quick parameter tracking.

Effects of exceeding stroke frequency of maximal effort on hand kinematics and hand propulsive force in front crawl.

This study aimed to assess kinematic and kinetic changes in front crawl with various stroke frequency (SF) conditions to investigate why swimming velocity (SV) does not increase above a certain SF (SFmax). Eight male swimmers performed 20 m front crawl four times. The first trial involved maximal effort, whereas SF was controlled during the next three trials. The instructed SFs were 100 (T100%), 110 (T110%), and 120% (T120%) of the SFmax. Through pressure measurement and underwater motion analysis, hand propulsive force (calculated by the difference between the palm and dorsal pressure value and the hand area) and the angle of attack of the hand were quantified, and differences between trials were assessed by a repeated-measures ANOVA. There was no difference in SV between the conditions, while the angle of attack during the latter half of the underwater stroke at T120% was smaller by 25.7% compared with T100% (p = 0.007). The lower angle of attack induced a lower pressure value on the palm that consequently caused a smaller hand propulsive force at T120% than T100% (p = 0.026). Therefore, the decrease in the angle of attack must be minimised to maintain the hand propulsive force.

Characteristics of gas from the fluidized bed gasification of refuse paper and plastic fuel (RPF) and wood biomass.

Energy recovery from small and medium scale waste thermal treatment facilities in the municipalities of Japan is challenging, owing to low power generation efficiency and high economic demands. Gas Engine (GE) generation is considered an efficient resource utilization method in these facilities. In this study, new and consistent feedstock, Refuse Paper and Plastic Fuel (RPF), and wood pellets were tested in an air-blown Fluidized Bed Gasifier (FBG) for syngas utilization in a GE. With temperatures ranging from 700 to 940 °C and varying Equivalence Ratios (ER) of 0.3-0.5, some of the most important product gas characteristics were analyzed, including the Lower Heating Value (LHV) and tar concentration levels. Gas composition results revealed that the concentration tendencies varied for the product gases CO, H2, and hydrocarbons, depending on the feedstock type, whereas the same tendencies were observed for CH4 and tar concentrations. Through the ER range, the LHV of product gas for RPF and wood pellets was 3.4-5.9 MJ/Nm3. Tar concentrations decreased to 2.5-14.0 g/Nm3-dry as the ER was raised. The optimal ER for LHV performance in GE generation was approximately 0.4 for RPF and wood pellets, and remaining tar concentrations were about 5.0 g/Nm3-dry at the gasifier exit.