Potential Impact of Climate Change on Residential Energy Consumption in Dhaka City

This study aimed to assess the impacts of climate change on residential energy consumption in Dhaka city of Bangladesh. The monthly electricity consumption data for the period 2011–2014 and long-term climate variables namely monthly rainfall and temperature records (1961–2010) were used in the study. An ensemble of six global circulation models (GCMs) of coupled model intercomparison project phase 5 (CMIP5) namely, BCCCSM1-1, CanESM2, MIROC5, MIROC-ESM, MIROC-ESM-CHEM, and NorESM1-M under four representative concentration pathway (RCP) scenarios were used to project future changes in rainfall and temperature. The regression models describing the relationship between historical energy consumption and climate variables were developed to project future changes in energy consumptions. The results revealed that daily energy consumption in Dhaka city increases in the range of 6.46–11.97 and 2.37–6.25 MkWh at 95% level of confidence for every increase of temperature by 1 °C and daily average rainfall by 1 mm, respectively. This study concluded that daily total residential energy demand and peak demand in Dhaka city can increase up to 5.9–15.6 and 5.1–16.7%, respectively, by the end of this century under different climate change scenarios.     

Characteristics of environmental pollution related with public complaints in an industrial shipbuilding complex, Korea

The shipbuilding industry of Korea, ranked number one in the world in annual amount of ship orders, has contributed to national economic growth; however, this has resulted in various environmental problems. Characteristics of environmental pollution, such as particulate matters, odor, and noise, which are closely related with public complaints, were evaluated in an industrial shipbuilding complex. The concentrations of PM-10 and TSP were significantly affected by the distance between the measurement site and shipbuilding workplace, as well as the height of the measurement site. Average PM-10 concentrations in the residential area ranged from 40.10 to 44.10 ??g/m³, which were not high in comparison with the ambient air quality standard and those of major cities in Korea. Paint particles could affect a wider area than typical particulate matters due to their generation and transport properties. The properties of odor in the study area were widely affected by the work intensity in shipyards and the temperature. Twenty-five out of total 54 samples collected in the residential area exceeded the dilution factor of 10, which is the tolerable limit adopted in Korea. Noise had an influence on a limited area due to the extinction effect with distance from the shipyards, while severe noise levels higher than 90 dB(A) were frequently found inside the shipyards.     

Application of an aerosol electrical mobility spectrum analyzer: Charged-particle polarity ratio measurement in the Antarctic and Arctic regions

An aerosol electrical mobility spectrum analyzer (AEMSA), developed at Hanyang University, was employed to investigate the particle charge characteristics in the Antarctic and Arctic regions. The particle charge characteristics in these areas were compared with the charging state in Ansan, South Korea, located in the midlatitude, where artificial factors, such as human activity, urbanization, and traffic, might result in a higher total concentration. Furthermore, in Ansan, South Korea, the charged-particle polarity ratio was very stable and was close to 1. However, notably different particle charge characteristics were obtained in the Antarctic and Arctic regions. The imbalance between the numbers of positively and negatively charged particles was evident, resulting in more positive charges on the atmospheric particles. On average, the positively charged particle concentrations in the Antarctic and Arctic areas were 1.4 and 2.8 times higher, respectively, compared with the negatively charged particles. The developed AEMSA system and the findings of this study provide useful information on the characteristics of atmospheric aerosols in the Antarctic and Arctic regions and can be further utilized to study particle formation mechanisms.     

Revised relative potency values for PCDDs, PCDFs, and non-ortho-substituted PCBs for the optimized H4IIE-luc in vitro bioassay

While the World Health Organization 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalency factors are useful estimates of relative potencies of mixtures when conducting risk assessments, they are not useful when comparing the results of bioassays such as the H4IIE-luc to concentrations of TCDD equivalents calculated from instrumental analyses. Since there are thousands of dioxin-like compounds (DLCs), one use of screening assays is to determine if all of the aryl hydrocarbon receptor (AhR) active DLCs in a mixture have been accounted for in instrumental analyses. For this purpose, bioassay-specific relative potency (ReP) values are needed. RePs of 21 polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and dioxin-like polychlorinated biphenyls that exhibit effects mediated through the AhR were determined by use of the H4IIE-luc assay. Different values of RePs are derived, depending on the statistical, curve-fitting methods used to derive them from the dose–response relationships. Here, we discuss the various methods for deriving RePs from in vitro data and their assumptions and effects on values of RePs. Full dose–response curves of 2,3,7,8-TCDD and other representative DLCs were used to estimate effective concentrations at multiple points (e.g., EC20-50-80), which were then used to estimate ReP of each DLC to 2,3,7,8-TCDD.     

Seasonal variation in long-range transported dust to a subtropical islet offshore northern Taiwan: Chemical composition and Sr isotopic evidence in rainwater

We investigated chemical and Sr isotopic composition of monthly rainwater collected on Peng-Chia-Yu (PCY) in northern Taiwan. Rainwater ⁸⁷Sr/⁸⁶Sr ratios, Na/Cl, Ca/Cl, Sr/Cl, Sr/Ca, NH₄/Cl, NO₃/Cl, SO₄/Cl and Na/Sr, showed clear seasonal cycles, reflecting mixture of loess carbonates (high Ca/Sr and more radiogenic ⁸⁷Sr/⁸⁶Sr) and seawater (low Ca/Sr and intermediate ⁸⁷Sr/⁸⁶Sr). Model results showed that the former source contributes up to 45% during the winter monsoon period, but seawater is the dominant Sr source in rainwater (>50%) at other times. Two anomalously low ⁸⁷Sr/⁸⁶Sr values occurred in July and August 1998, coinciding with the Merapi eruption in Indonesia. Air-mass backward trajectories and the geochemical and isotopic compositions in rainwater and Merapi lava (i.e. Ca/Sr = 100 and ⁸⁷Sr/⁸⁶Sr = 0.705400) suggested that the Merapi eruption delivered ash across the western equatorial Pacific to PCY. Aerosols leaching experiments were conducted to examine the impact of the 1998 eruption, demonstrating that only a minor terrestrial signature can be extracted by distilled water, implying rapid dispatch of volcanic gases or high-efficiency dissolution of ash related substance in acidic rains.     

Assessment of airborne environmental bacteria and related factors in 25 underground railway stations in Seoul,Korea

This study assessed bacterial concentrations in indoor air at 25 underground railway stations in Seoul, Korea, and investigated various related factors including the presence of platform screen doors (PSD), depth of the station, year of construction, temperature, relative humidity, and number of passengers. A total of 72 aerosol samples were collected from all the stations. Concentrations of total airborne bacteria (TAB) ranged from not detected (ND) to 4997 CFU m^?3, with an overall geometric mean (GM) of 191 CFU m^?3. Airborne bacteria were detected at 23 stations (92%) and Gram-negative bacteria (GNB) were detected at two stations (8%). TAB concentrations of four stations (16%) exceeded 800 CFU m^?3, the Korea indoor bio-aerosol guideline. The results of the study showed that TAB concentrations at the stations without PSD showed higher TAB concentrations than those with PSD, though not at statistically significant levels. TAB concentrations of deeper stations revealed significantly higher levels than those of shallower stations. Based on this study, it is recommended that mitigation measures be applied to improve the indoor air quality (IAQ) of underground railway stations in Seoul, with focused attention on deeper stations.     

Prioritization of water management for sustainability using hydrologic simulation model and multicriteria decision making techniques

The objective of this study is to develop an alternative evaluation index (AEI) in order to determine the priorities of a range of alternatives using both the hydrological simulation program in FORTRAN (HSPF) and multicriteria decision making (MCDM) techniques. In order to formulate the HSPF model, sensitivity analyses of water quantity (peak discharge and total volume) and quality (BOD peak concentrations and total loads) are conducted and a number of critical parameters were selected. To achieve a more precise simulation, the study watershed is divided into four regions for calibration and verification according to landuse, location, slope, and climate data. All evaluation criteria were selected using the Driver–Pressure–State–Impact–Response (DPSIR) model, a sustainability evaluation concept. The Analytic Hierarchy Process is used to estimate the weights of the criteria and the effects of water quantity and quality were quantified by HSPF simulation. In addition, AEIs that reflected residents' preferences for management objectives are proposed in order to induce the stakeholder to participate in the decision making process.     

Relationship between road traffic noisescape and urban form in Hong Kong

This paper reports on a study which explored the possible relationship between road traffic noisescape and urban form in Hong Kong. A total of 212 residential complexes from 11 contrasting urban forms were sampled, and their noise levels assessed both at dwelling and neighbourhood scales by noise mapping. Its findings indicate that residential complexes with different urban forms have significantly different noisescape attributes. There is a strong correlation between the noise characteristics and morphological indicators at the dwelling scale. A less obstreperous noisescape is associated with urban forms with lower road and building densities, and with building arrangements which provide self-noise screening. These findings suggest that urban form is an influential determinant of the noisescape in the urban environment, and they point to the need to rethink the conventional approach to managing the urban acoustic environment.     

Nitrogen and phosphorus removal for swine wastewater by ammonium crystallization and intermittent aeration process

Abstract

A process on crystallized precipitation of ammonium by adding magnesium salt and phosphate was carried out to improve C/N ratio in swine wastewater. After completion of crystallized precipitation of ammonium, an intermittent aeration process with aeration and non‐aeration periods alternated at interval of 1:1 hr day^‐1 is used for the improved swine wastewater (T‐N/BOD=0.14: BOD=8200 mg/liter and T‐N=1166 mg/liter). The results obtained from the experiment show that the removal ratios of T‐N and NH₄‐N are 91% and 99%, respectively. T‐P is not removed, while the removal ratio of PO₄‐P is 60% as 3% of CaCl₂ liquid is added. The results also indicate that dilution with water is effective to improve the removal of phosphorus even if raw swine wastewater contains high concentrations of T‐N, T‐P, BOD, and TOC.     

Reduction of tar using cheap catalysts during sewage sludge gasification

Solid-fuel conversion or gasification study of sewage sludge and energy recovery has become increasingly important because energy recovery and climate change are emerging issues. Various types of catalysts, such as dolomite, steel slag and calcium oxide, were tested for tar reduction during the sewage sludge gasification process. For the experiments on sewage sludge gasification reactions and tar reduction using the catalysts, a fixed bed of laboratory-scale experimental apparatus was set up. The reactor was made of quartz glass using an electric muffle furnace. The sewage sludge samples used had moisture contents less than 6%. The experimental conditions were as follows: sample weight was 20 g and reaction time was 10 min, gasification reaction temperature was from 600 to 800°C, and the equivalence ratio was 0.2. The quantity of catalysts was 2–6 g, and temperatures of catalyst layers were 500–700°C. As the reaction temperature increased up to 800°C, the yields of gaseous products and liquid products increased, whereas char and tar products decreased, showing effects on gas product compositions. These results were considered to be due to the increase of the water-gas reaction and Boudouard reaction. In the case of experiments with catalysts, dolomite (4 g), steel slag (6 g) and calcium oxide (6 g) were used. When the temperature of catalysts increased, the weight of the tar produced decreased with different cracking performances by different catalysts. Reforming reactions were considered to occur on the surface of dolomite, steel slag and calcium oxide, causing cracking of the hydrocarbon structure, which eventually showed reduced tar generation.