The objective of this research is to examine the effects of stock market on air pollution in Malaysia during the period 1980-2017. To realize this aim, a nonlinear autoregressive distributed lag (ARDL) model is constructed. The short results in general revealed that the increase in stock markets will increase CO2 emissions and its significance increases in the long run. Moreover, the decline in stock market will reduce Malaysia's CO2 emissions but only in the long run. From the outcomes obtained, a number of policy recommendations were provided for the investigated country.
The pollution of water resources due to the disposal of industrial wastes that have organic material like phenol is causing worldwide concern because of their toxicity towards aquatic life, human beings and the environment. Phenol causes nervous system damage, renal kidney disease, mental retardation, cancer and anaemia. In this study, magnetic palm kernel biochar is used for removal of phenol from wastewater. The effect of parameters such as pH, agitation speed, contact time and magnetic biochar dosage are validated using design of experiments. The statistical analysis reveals that the optimum conditions for the highest removal (93.39%) of phenol are obtained at pH of 8, magnetic biochar dosage of 0.6 g, agitation speed at 180 rpm and time of 60 min with the initial concentration of 10 mg/L. The maximum adsorption capacities of phenol were found to be 10.84 mg/g and Langmuir and Freundlich isotherm models match the experimental data very well and adsorption kinetic obeys a pseudo-second order. Hence, magnetic palm kernel can be a potential candidate for phenol removal from wastewater.
Sustainable development inculcates the process of preserving the environment for future generations while maintaining existing human needs. This study attempts to empirically investigate the relationship between CO2 emissions, GDP, energy consumption, and imports and exports using yearly data between 1980 and 2014 for the panel of eight developing countries (i.e., Bangladesh, Egypt, Iran, Indonesia, Malaysia, Nigeria, Pakistan, and Turkey). All the tests for cointegration establish the long-run association among the variables and confirm the environmental Kuznets curve (EKC) hypothesis for the panel of eight countries. GDP and energy consumption remained significant factors for emission intensity both in the long and short run. However, exports found to be positive factor for emissions in the long run only and imports spur emissions in the short run. The country-specific results validate EKC hypothesis for Bangladesh, Iran, Nigeria, Pakistan, and Turkey. The findings are policy oriented and suggest that the countries' economic growth along with energy consumption and exports are highly emission intensive which require necessary adjustments at sustainable development policy front.
Human health is threatened by significant emissions of heavy metals into the urban environment due to various activities. Various studies describing health risk analyses on soil and dust have been conducted previously. However, there are limited studies that have been carried out regarding the potential health risk assessment of heavy metals in urban road dust of < 63-μm diameter, via incidental ingestion, dermal contact, and inhalation exposure routes by children and adults in developing countries. Therefore, this study evaluated the health risks of heavy metal exposure via ingestion, dermal contact, and inhalation of urban dust particles in Petaling Jaya, Malaysia. Heavy metals such as lead (Pb), chromium (Cr), zinc (Zn), copper (Cu), and manganese (Mn) were measured using dust samples obtained from industrial, high-traffic, commercial, and residential areas by using inductively coupled plasma mass spectrometry (ICP-MS). The principal component and hierarchical cluster analysis showed the dominance of these metal concentrations at sites associated with anthropogenic activities. This was suggestive of industrial, traffic emissions, atmospheric depositions, and wind as the significant contributors towards urban dust contamination in the study sites. Further exploratory analysis underlined Cr, Pb, Cu, and Zn as the most representative metals in the dust samples. In accommodating the uncertainties associated with health risk calculations and simulating the reasonable maximum exposure of these metals, the related health risks were estimated at the 75th and 95th percentiles. Furthermore, assessing the exposure to carcinogenic and non-carcinogenic metals in the dust revealed that ingestion was the primary route of consumption. Children who ingested dust particles in Petaling Jaya could be more vulnerable to carcinogenic and non-carcinogenic risks, but the exposure for both children and adults showed no potential health effects. Therefore, this study serves as an important premise for a review and reformation of the existing environmental quality standards for human health safety.
A rapid growth in the development of power generation and transportation sectors would result in an increase in the carbon dioxide (CO2) concentration in the atmosphere. As it will continue to play a vital role in meeting current and future needs, significant efforts have been made to address this problem. Over the past few years, extensive studies on the development of heterogeneous catalysts for CO2 methanation have been investigated and reported in the literatures. In this paper, a comprehensive overview of methanation research studies over lanthanide oxide catalysts has been reviewed. The utilisation of lanthanide oxides as CO2 methanation catalysts performed an outstanding result of CO2 conversion and improvised the conversion of acidity from CO2 gas to CH4 gas. The innovations of catalysts towards the reaction were discussed in details including the influence of preparation methods, the structure-activity relationships as well as the mechanism with the purpose of outlining the pathways for future development of the methanation process.
Lignocellulosic biomass waste is a cheap, eco-friendly, and sustainable raw material for a wide array of applications. In the present study, an easy, fast, and economically feasible route has been proposed for the preparation of different zero-valent metal nanoparticles (ZV-MNPs) based on Cu, Co, Ag, and Ni NPs using empty fruit bunch (EFB) biomass residue as support material. The catalytic efficiency of ZV-MNPs/EFB catalyst was investigated against five model pollutants, such as methyl orange (MO), congo red (CR), methylene blue (MB), acridine orange (AO), and 4-nitrophenol (4-NP) using NaBH4 as a source of hydrogen and electron. Comparative study revealed that among as-prepared ZV-MNPs/EFB catalysts, Cu-NPs immobilized onto EFB (Cu/EFB) exhibited maximum catalytic efficiency towards pollutant abasement. Degradation reactions were highly efficient, and were completed within a short time (4 min) in case of MO, CR, and MB, whilst AO and 4-NP were reduced in less than 15 min. Kinetic investigation revealed that the degradation rate of model pollutants accorded with pseudo-first order model. Furthermore, supported catalysts were easily recovered after the completion of experiment by simply pulling the catalyst from reaction system. Recyclability tests performed on Cu/EFB revealed that more than 97% of the reduction was achieved in case of MO dye for four successive cycles of reuse. The as-prepared heterostructure showed multifunctional properties, such as enhanced uptake of contaminants, high catalytic efficiency, and easy recovery, hence, offers great prospects in wastewater purification.
By growing urban population, Iran faces numerous environmental issues and solid waste management is on the top of these problems. Studies showed that a daily average of 700-1000 g of wastes are produced per person in Iran, in which organic waste accounts for a significant amount. On the other hand, hospital waste represents a part of the wastes, which need careful consideration from the environmental point of view. In the present study, the amount, composition, and management of urban and hospital wastes were evaluated in 7 Iranian metropolises, which account for about 30% of the population and produce about 35% of the country wastes. Based on prior surveys, landfill method is the current main method for waste management in these cities, which is generally not completely sanitary and therefore causes many environmental problems. The other common methods for waste management in these cities are composting of organic wastes, and the use of waste conversion methods to energy. However, the latter is ongoing only in Tehran which also includes some limitations. Therefore, the study also evaluated the future perspectives and feasibility of waste-to-energy conversion as a promising economic route for waste disposal.
Nowadays, the current synthesis techniques used in industrial production of nanoparticles have been generally regarded as nonenvironmentally friendly. Consequently, the biosynthesis approach has been proposed as an alternative to reduce the usage of hazardous chemical compounds and harsh reaction conditions in the production of nanoparticles. In this work, pure, iron (Fe)-doped and silver (Ag)-doped zinc oxide (ZnO) nanoparticles were successfully synthesized through the green route using Clitoria ternatea Linn. The optical, chemical, and physical properties of the biosynthesized ZnO nanoparticles were then analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), UV-Vis diffuse reflectance spectroscopy (DRS), zeta potential measurement, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and surface analysis. The biosynthesized ZnO nanoparticles were crystallized with a hexagonal wurtzite structure and possessed smaller particle sizes than those of commercially or chemically produced samples. The existence of biomolecules to act as reducing and stabilizing agents from C. ternatea Linn aqueous extract was confirmed using FTIR analysis. The biosynthesized ZnO nanoparticles mainly comprised of negatively charged groups and responsible for moderately stable dispersion of the nanoparticles. All these properties were favorable for the sonocatalytic degradation of Congo red. Sonocatalytic activity of ZnO nanoparticles was studied through the degradation of 10 mg/L Congo red using ultrasonic irradiation at 45 kHz and 80 W. The results showed that the sonocatalytic degradation efficiency of Congo red in the presence of biosynthesized ZnO nanoparticles prepared at 50 °C for 1 h could achieve 88.76% after 1 h. The sonocatalytic degradation efficiency of Congo red in the presence of Ag-doped ZnO was accelerated to 94.42% after 10 min which might be related to the smallest band gap energy (3.02 eV) and the highest specific surface area (10.31 m2/g) as well as pore volume (0.0781 cm3/g). Lastly, the biosynthesized ZnO nanoparticles especially Ag-doped ZnO offered significant antibacterial potential against Escherichia coli which indicated its ability to inhibit the normal growth and replication of bacterial cells. These results affirmed that the biosynthesized ZnO nanoparticles could be used as an alternative to the current chemical compounds and showed a superior sonocatalytic activity toward degradation of Congo red.
This research article aims to investigate the moderating role of financial development in Environmental Kuznets Curve (EKC) in the context of Malaysia for the period 1970-2016. As the time series variables are integrated of different order therefore, Auto-Regressive Distributed Lag (ARDL) model has been employed to estimate the long-run equilibrium relationship among the variables. The results indicate that EKC does exist for Malaysia and financial development has negative impact on carbon emission. Moreover, financial development is found to have significant moderating impact on income environment relation. More financial development brings early turning point of the EKC. The results recommend that financial development can be used as one of the policy measures to reduce the environmental cost of economic growth in Malaysia.
This study critically evaluates two COP proposals on Malaysia that have been under consideration to reduce climate damage. A top-down disaggregation framework deploying an "Empirical Regional Downscaling Dynamic Integrated Model of Climate and the Economy" is used to evaluate the local government climate roadmap and Malaysia's emissions reduction agendas under COP21 and subsequently COP22 proposals. The findings show that the costs from climate damage over the period 2010-2110 under the Malaysian Optimal Climate Action scenario will amount to MYR5,483 (US$1589) billion. The commensurate climate damage costs under the COP21 and COP22 scenario would be MYR5, 264 (US$1526) billion. Thus, the effective proposal for reducing climate damage in Malaysia over the period 2010-2110 is the COP22 time-adjusted COP21 proposal but there are a number of macroeconomic cost implications for savings and consumption that policy makers must address before acting.
Southeast Asia has undergone rapid developments in terms of urbanization, economic and population growth. The progress in sewerage treatment infrastructure has not kept pace with such developments. The inadequacy and inefficiency of sewerage systems has prompted the release of untreated sewage into the aquatic environment of Southeast Asia causing many waterborne illnesses since surface water is utilized for recreational, agricultural and aquaculture purposes and, above all, as a source of water intake in Southeast Asia. This paper will review the current data on molecular markers of sewage pollution including sterols and linear alkylbenzenes (LABs) in Southeast Asian aquatic environment to clarify the state of sewage pollution and the competence of sewage treatment plants (STPs) in this area. Despite the importance of sewage pollution research in the region, the number of studies using molecular markers to trace the sources of sewage pollution is limited. So far, indicators of sewage pollution have been investigated in aquatic environments of Indonesia, Vietnam, Malaysia, the Philippines, Thailand, Cambodia and Brunei among Southeast Asian countries. The concentrations and diagnostic ratios of faecal sterols and LABs show the release of untreated and primary treated urban waste into water bodies of these countries. Further studies are required to fill the data gaps in Southeast Asia and come to a better understanding of the trends of sewage pollution in this part of the world. Graphical abstract.
Alternative energy policies targeting the adoption of hydrogen fuel cell vehicles (HFCVs) could have significant positive impacts on Malaysia's ability to meet both its carbon reduction goal and its energy security needs. The transport sector generally contributes heavily to carbon emissions, and is also difficult to decarbonize because of the costs associated with many greener options. This study explores the possibility of decarbonizing the Malaysian transport sector by promoting the use of hydrogen vehicles, and analyzes the adoption challenges and economic obstacles (especially public acceptance) associated with introducing HFCVs. This study contends that the adoption challenges of this new technology can be overcome through the use of development strategies outlined. This study also addresses the regulatory framework that Malaysia (and other countries) might use to overcome common policy adoption challenges of HFCVs.
The primary objective of mobile phone technology is to achieve communication with any person at any place and time. In the modern era, it is impossible to ignore the usefulness of mobile phone technology in cases of emergency as many lives have been saved. However, the biological effects they may have on humans and other animals have been largely ignored and not been evaluated comprehensively. One of the reasons for this is the speedy uncontrollable growth of this technology which has surpassed our researching ability. Initiated with the first generation, the mobile telephony currently reaches to its fifth generation without being screened extensively for any biological effects that they may have on humans or on other animals. Mounting evidences suggest possible non-thermal biological effects of radiofrequency electromagnetic radiation (RF-EMR) on brain and behavior. Behavioral studies have particularly concentrated on the effects of RF-EMR on learning, memory, anxiety, and locomotion. The literature analysis on behavioral effects of RF-EMR demonstrates complex picture with conflicting observations. Nonetheless, numerous reports suggest a possible behavioral effect of RF-EMR. The scientific findings about this issue are presented in the current review. The possible neural and molecular mechanisms for the behavioral effects have been proposed in the light of available evidences from the literature.
The rapid increase in urbanization has given rise to the need of proper waste management. Within municipal waste, the plastic waste is a growing concern which is causing severe harm to our ecosystem. If ignored, this problem will have harmful effects on both human and wildlife. Therefore, this study aims to find out the factors that influence the recycling behavior patterns of consumers regarding plastic waste. The variables from the theory of planned behavior were adopted to study the behavior of consumers toward recycling plastic waste. The data was collected from 243 residents of Karachi-metropolitan city of Pakistan. The partial least square-structural equation modelling was applied to analyze the data. The findings of the current study reveal that different consumers' attributes and attitudes trigger different types of recycling behavior when it comes to waste disposal. Pressure from family and friends and perceived behavioral control trigger the behavior of reselling the waste plastic products while consumer's awareness of consequences and personal attitude toward proper waste disposal leads to reuse or donating that product to someone who can use that plastic product. The understanding of these consumer attributes may help to shape the behavioral outcomes in order to manage waste disposal. This study will be beneficial for business managers looking to improve reverse logistics as well as government/municipal policy makers and academics/researchers who are interested in a solution-oriented study.
The current work aimed to investigate the degradation of the triclocarban (TCC) in aqueous solution using a modified zeolite/TiO2 composite (MZTC) synthesized by applying the electrochemical anodization (ECA). The synthesis process was conducted at different voltages (10, 40, and 60) V in 1 h and using electrophoresis deposition (EPD) in doping zeolite. The MZTC was covered with the array ordered, smooth and optimum elongated nanotubes with 5.1 μm of the length, 120.3 nm of the inner diameter 14.5 nm of the wall thickness with pure titanium and crystalline titania as determined by FESEM/EDS, and XRD. The kinetic study by following Langmuir-Hinshelwood(L-H) model and pseudo first order, the significant constant rate was obtained at pH 11 which was 0.079 ppm/min, 0.75 cm2 of MZTC catalyst loading size achieved 0.076 ppm/min and 5 ppm of TCC initial concentration reached 0.162 ppm/min. The high-performance liquid chromatography (HPLC) analysis for mechanism study of TCC photocatalytic degradation revealed eleven intermediate products after the whole process of photocatalysis. In regard of toxicology assessment by the bacteria which is Photobacterium phosphoreum, the obtained concentration of TCC at minute 60 was less satisfied with remained 0.36 ppm of TCC was detected indicates that the concentration was above allowable level. Where the allowable level of TCC in stream is 0.1 ppm.
Since the development of the service sector and renewable energy reduce fossil-based energy consumption which mitigates CO2 emissions and this nexus provides a better understanding of the environmental sustainability. Considering the substantially increasing contribution of service sector and tremendous potential for renewable energy in ASEAN5 countries, leaning forward from ASEAN's energy and growth nexus, this study examines the impact of service sector contribution and renewable energy on the environmental quality of ASEAN5 using annual data from 1990 to 2018. The results of the fully modified ordinary least squared, dynamic ordinary least squared, and canonical co-integrating regressions depicted that the service sectors of Thailand, the Philippines, and Singapore augment CO2 emissions; however, the service sectors of Malaysia and Indonesia could reduce CO2 emissions. The increasing share of renewable energy can enhance environmental quality, but its magnitude varies in ASEAN5 economies; non-renewable energy, population, and economic development deteriorate the environment. Our results confirm the existence of environmental Kuznets curve in all the ASEAN5; the Gregory-Hansen test confirmed that results are robust. Finally, the Granger causality designated that economic development and non-renewable energy have a significant causal relationship with CO2 emission of ASEAN5 countries. These findings suggest that the ASEAN5 economies need to optimize their economic structure for promoting sustainable development in the long run.Graphical abstract.
Oil spills are a major contributor to water contamination, which sets off a significant impact on the environment, biodiversity, and economy. Efficient removal of oil spills is needed for the protection of marine species as well as the environment. Conventional approaches are not efficient enough for oil-water separation; therefore, effective strategies and efficient removal techniques (and materials) must be developed to restore the contaminated marine to its normal ecology. Several research studies have shown that nanotechnology provides efficient features to clean up these oil spills from the water using magnetic nanomaterials, particularly carbon/polymer-based magnetic nanocomposites. Surface modification of these nanomaterials via different techniques render them with salient innovative features. The present review discusses the advantages and limitations of conventional and advanced techniques for the oil spills removal from wastewater. Furthermore, the synthesis of magnetic nanocomposites, their utilization in oil-water separation, and adsorption mechanisms are discussed. Finally, the advancement and future perspectives of magnetic nanocomposites (particularly of carbon and polymer-based magnetic nanocomposites) in environmental remediation are presented.
Studies have proven that client satisfaction (CS) is greatly affected by the nature of construction practices on site. However, not much attention has been given to CS in projects that adopt green construction practices (GCPs). This study examines the effect of GCPs on CS, and the means by which CS can be achieved through health and safety performance (HSP). This study also analyses how the relationship between HSP and CS could vary depending on the level of GCPs adopted. A questionnaire with 27 items drawn from literature was used in collecting data from class A contractors in Nigeria. The study's hypotheses were tested using the partial least squares structural equation modelling (PLS-SEM) technique. The findings of the study reveal that GCPs have a positive effect on CS. HSP proved to only partially mediate the relationship between GCPs and CS. The findings also show that the effect of HSP on CS is moderated by GCPs with the stronger effect from projects with low adoption of GCPs. The study's findings highlight the pivotal role of HSP in ensuring CS in construction projects that adopt GCPs. This study makes practical contributions to the body of existing knowledge by highlighting the need for concerted efforts by contractors such as investing in health and safety training and ensuring site workers wear personal protective equipment aimed at adhering to acceptable health and safety standards. This can be achieved through provision of funds for safety activities, monitoring, and supervision of workers to guarantee HSP which translates to CS while adopting GCPs. However, the obstacles to these are the lack of safety culture by construction organizations, lack of enlightenment on the part of construction site workers, and poor safety climate on the construction project site. Additionally, the study provides greater insight on the practice of green construction among contractors by showing that the effect of HSP on CS would differ considerably on account of the level of GCPs adopted.
This experimental research was conducted to study the combined effect of agricultural by-product wastes on the properties of concrete. The coconut shell ash (CSA) was utilized to substitute cement content ranging from 0 to 20% by weight of total binder and sugarcane bagasse ash (SCBA) to substitute fine aggregates (FA) ranging from 0 to 40% by weight of total FA. In this regard, a total of 300 concrete specimens (cylinders and cubes) were prepared using 1:1.5:3 mix proportions with a 0.52 water-binder ratio. The study investigated the workability, density, permeability, and mechanical properties in terms of compressive and splitting tensile strengths. Additionally, the total embodied carbon for all mix proportions was calculated. It was observed that with an increase in CSA and SCBA contents, the workability, density, and permeability reduced significantly. Due to CSA and SCBA being pozzolanic materials, a gain in compressive and splitting tensile strengths was observed for certain concrete mixes, after which the strength decreased. The increase in embodied carbon of SCBA increased the total embodied carbon of concrete; however, it can be said that C15S40 which consists of 15% CSA and 40% SCBA is the optimum mix that achieved 28.75 MPa and 3.05 MPa compressive and tensile strength, respectively, a reduction of 4% total embodied carbon.