This study aims to analyze the spatial distribution of the epidemic spread and the role of the physical, social, and economic characteristics in this spreading. A geographically weighted regression (GWR) model was built within a GIS environment using infection data monitored by the Iraqi Ministry of Health records for 10 months from March to December 2020. The factors adopted in this model are the size of urban interaction areas and human gatherings, movement level and accessibility, and the volume of public services and facilities that attract people. The results show that it would be possible to deal with each administrative unit in proportion to its circumstances in light of the factors that appear in it. So, there will not be a single treatment for all areas with different urban characteristics, which sometimes helps not to stop social and economic life due to the imposition of a comprehensive ban on movement and activities. Therefore, there will be other supportive policies other than the ban, depending on the urban indicators for each region, such as reducing external movement from it or relying on preventing public activities only.

Environmental degradation is frequently cited as one of the eminent issues in the modern era. To limit environmental degradation, prior literature discerns several macroeconomic, socio-economic, and institutional factors that affect environmental degradation. However, the relationship between geopolitical risk and environmental degradation is understudied in the previous literature. To fill this gap, the inquiry at hand aims to scrutinize the influence of geopolitical risk on environmental degradation for E7 countries while controlling the effect of renewable energy, non-renewable energy, and GDP. Further, we utilize both the ecological footprint and CO₂ emissions as proxies of environmental degradation and employ second-generation panel methods for robust findings. In addition to this, the present study uses augmented mean group (AMG) estimator to provide long-run relationship among the selected variables. The findings from the AMG estimator expound that there exists environmental Kuznets curve (EKC) for E7 countries. Moreover, renewable energy ameliorates environmental quality because it plunges both ecological footprint and CO₂ emissions. On the contrary, non-renewable energy consumption escalates both ecological footprint and CO₂ emissions. Finally, geopolitical risk tends to decrease CO₂ emissions as well as ecological footprint. Our findings deduce a few policy implications to replenish environmental quality. For instance, the share of renewables in the energy mix should be surged to ameliorate the environmental quality. Further, to control both the geopolitical risk and environmental degradation at the same time, policymakers should put forward reforms and initiatives (e.g., policies to escalate R&D, technological innovations, and tax exemptions on imports of renewables) that can help to improve environmental quality without affecting geopolitical risk. At times of low geopolitical risk, environmental degradation will surge; therefore, the rate of environmental control taxes should be increased by the policymakers.

This paper aims to examine the nexus among carbon dioxide (CO₂) emissions, urbanization level and industrial structure in North China over the period 2004–2019, according to an expanded Cobb-Douglas production function. The panel econometric techniques are employed to complete the empirical analysis, including cross-sectional correlation test, panel unit root test, panel co-integration test, and panel Granger causality test. The empirical results support the long-term equilibrium relationship among CO₂ emissions, urbanization level and industrial structure in North China, and the urbanization level contributes most to CO₂ emissions, followed by fossil energy consumption. Furthermore, the bidirectional causality between CO₂ emissions and urbanization level and unidirectional causality from industrial structure to CO₂ emissions are found in North China, indicating that urbanization level and industrial structure have significant impacts on CO₂ emissions. Finally, according to the empirical findings, several policy suggestions are proposed for the purpose of reducing CO₂ emissions in North China.

For decades, the rapid urbanization and economic development in China inevitably lead to the increase of household energy demand and CO₂ emissions. Existing studies regard the household sector as an exogenous sector unrelated to production, ignoring that the wages, goods, and services provided by production sectors will affect the consumption of the household sector. This paper analyzes the impact of the household sector on production sectors and the total CO₂ emissions by establishing a semi-closed environmentally extended input–output model in China from 2007 to 2017. Through the calculation of index of the power of dispersion and index of sensitivity of dispersion, the index of sensitivity of dispersion of household is large, and household has push to several sectors’ CO₂ emissions. Furthermore, we explore the drivers of China’s household CO₂ emissions using structural decomposition analysis and claim that consumption per capita and urbanization rate are the dominant factors driving household CO₂ emissions, while carbon intensity and economic structure are the main factors inhibiting household CO₂ emissions. Our research shows a clear picture of sector linkages and driving forces of household CO₂ emissions, providing strong evidence for the development of China’s household CO₂ reduction policies.

We prepared a double-layer magnetic nanocomposite Fe₃O₄@ZIF-8@ZIF-67 by layer-by-layer self-assembly. Fe₃O₄@ZIF-8@ZIF-67 was used to remove tetracycline from an aqueous solution via a combination of adsorption and Fenton-like oxidation. Depending on the outstanding porous structure of the Fe₃O₄@ZIF-8@ZIF-67, a high adsorption capacity for tetracycline was 356.25 mg g⁻¹, with > 95.47% removal efficiency within 100 min based on Fenton-like oxidation. To better understand the mechanisms involved in integrated adsorption and Fenton-like oxidation, various advanced characterization techniques were used to monitor the changes in morphology and composition of Fe₃O₄@ZIF-8@ZIF-67 before and after removal of tetracycline. Scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) all supported adsorption and Fenton oxidation of tetracycline. This study extends the application of Fe₃O₄@ZIF-8@ZIF-67 for environmental remediation.

In this study, the concentration of ambient persistent organic pollutants (POPs) such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) were measured for 12 months in urban and semi-urban areas using a passive air sampler. During the sampling period, a total of 14 PAH (∑₁₄PAH) concentrations measured in urban and semi-urban areas were found to be 54.4 ± 22.6 ng/m³ and 51.7 ± 34.3 ng/m³, respectively. Molecular diagnostic ratios (MDRs) were used to determine PAH sources. According to the MDR values, combustion sources were the most important PAH sources in both sampling areas. However, since the urban area is close to the industrial zone, the combustion sources occurred at high temperatures (> 800 °C), while the sources in the semi-urban area generally consisted of petrogenic fuel combustion. ∑₅₀PCB concentrations measured in the urban and semi-urban areas were found to be 522.5 ± 196.9 pg/m³ and 439.5 ± 166.6 pg/m³, respectively. Homologous group distributions were used to determine the source of PCBs. According to the homologous group distributions, tri-, tetra-, and penta-chlorinated PCBs were dominant in both sampling areas. ∑₁₀OCP concentrations measured in urban and semi-urban areas were found as 242.5 ± 104.6 pg/m³ and 275.9 ± 130.9 pg/m³, respectively. Also, α-HCH/γ-HCH and β-/(α + γ)-HCH ratios were used to determine the source of OCPs. Lindane was the predominant OCP in both sampling areas.

The paper presents the photodegradation process of one-, two- and three-component dye mixtures by ZnO-SnO₂ nanoparticles. After 60 min of running the processes, the dye removal efficiencies of 76.44, 72.69, 62.43, 77.00 and 92.46% for MB, RB, TB, MO and YQ degradation, respectively, were obtained. For binary and ternary systems, dye removal efficiencies for all cases exceeded 70%. When the binary and ternary dye mixtures were tested, the photodegradation efficiencies of ZnO-SnO₂ were similar to those of the single mixtures, indicating that this material could be used in industrial applications in the future. The focus of the study was to investigate the effect of sorption on photodegradation efficiency and the presence of both cationic and anionic dyes on their degradation efficiency under UV light. The significance of the effect of sorption on the degradation efficiency allowing the interaction of the catalyst with the dyes removed was confirmed. The main factor influencing sorption and consequently photocatalysis was the nature of the dye. It was confirmed that the positively charged ZnO-SnO₂ surface effectively sorbs the dyes and causes their degradation.

This study reports the concentrations of trace metals in core sediments profile from the coastal and four rivers estuary in the Kuching Division of Sarawak, Malaysia, and the controlling mechanisms influencing their availability in sediments of the studied area. The bonding of trace metals with non-mobile fractions was confirmed with the sequential extraction. Inductively coupled plasma–optical emission spectroscopy (ICP–OES) was used to measure the concentrations of the trace metals. Granulometric analyses were performed using normalized sieve apertures to determine the textural characteristics of the sediments. Enrichment factor was used to evaluate the level of metal enrichment. Heavy metals concentrations in sediment samples varied in the range: Pb (8.9–188.9 mg/kg d.w.), Zn (19.4–431.8 mg/kg d.w.), Cd (0.014–0.061 mg/kg d.w.), Ni (6.6–33.4 mg/kg d.w.), Mn (2.4–16.8 mg/kg d.w.), Cu (9.4–133.3 mg/kg d.w.), Ba (1.3–9.9 mg/kg d.w.), As (0.4–7.9 mg/kg d.w.), Co (0.9–5.1 mg/kg d.w.), Cr (1.4–7.8 mg/kg d.w.), Mg (68.8–499.3 mg/kg d.w.), Ca (11.3–64.9 mg/kg d.w.), Al (24.7–141.7 mg/kg d.w.), Na (8.8–29.4 mg/kg d.w.), and Fe (12,011–35,124.6 mg/kg d.w.). The estimated results of the enrichment factor suggested enrichments of Pb, Zn, and Cu in all the core sediment samples and depths at all sites. The other trace metals showed no enrichments in almost all the sampled stations. Continuous accumulation of Pb, Zn, and Cu metals over a period can be detrimental to living organisms and the ecology. The results obtained from the statistical analyses suggested that the deposition of trace metals in the studied sites is due to anthropogenic inputs from the adjacent land-based sources.

Aegle marmelos (L.) Correa belongs to the family Rutaceae is generally known as “bael fruit tree” occuring across the south Asian countries. The current investigation screened the main derivatives from crude ethanolic extracts of the Bael tree leaf and evaluated activity effects on the larvae and adults of Aedes aegypti (L.) Dengue vector mosquito and a non-target aquatic predator. The GC-MS results showed that the peak area was found to be profound in N-methyl-1-adamantaneacetamide (N-M 1a) followed by oleic acid (OA) with 63.08 and 11.43% respectively. The larvicidal activity against the fourth instar larvae and the crude Ex-Am showed prominent mortality rate (93.60%) at the maximum dosage of 100 ppm. The mortality rate of N-M 1a and OA was occurred at 10 ppm (97.73%) and 12 ppm (95.4%). The repellent activity was found to be prominent at crude Ex-Am (50 ppm) as compared to the pure compounds (N-m 1a and OA) with maximum protection time up to 210 min. The non-target screening of Ex-Am, N-M 1a, and OA on mosquito predator Tx. splendens showed that they are scarcely toxic even at the maximum dosage of 1000 ppm (34.13%), 100 ppm (27.3%), and 120 ppm (31.3%) respectively. Thus, the present investigation clearly proved that the crude Ex-Am and their major derivatives Nm 1-a and OA showed their acute larval toxicity as well as potential mosquito repellent against the dengue mosquito and eco-safety against the mosquito predator.

Although heavy metal pollution has developed into a major global environmental problem, most research has focused on specific elements, especially arsenic (As) and selenium (Se), and on the health risks to people in polluted areas or by occupation. This study investigated the urine of 480 participants from Guangzhou with a population of 18 million and targeted nine heavy metals: As, Se, chromium (Cr), manganese (Mn), nickel (Ni), cadmium (Cd), lead (Pb), antimony (Sb), and mercury (Hg). The heavy metals were widely detected, of which As, Se, Cd, and Pb all exceed 98%. Among the toxicants, As showed the highest concentration, followed by Se with 40.5 and 35.4 μg/L, respectively. The heavy metal levels from suburban subjects were generally higher than those in urban subjects (except for Sb), and the Cd level of males was lower than that of females. Concentrations were related to age, body mass index, alcohol consumption, and smoking. According to the health risk assessment, most subjects experienced potential non-carcinogenic risk from As, Cd, Se, and Hg, which accounted for 38.2%, 8.83%, 8.31%, and 3.38%, respectively. The carcinogenic risk of As and Cd surpassed the risk level of 10⁻⁶, and 90.1% and 35.4% of the subjects, respectively, exceeded 10⁻⁴, an unacceptable risk level. More attention to the high carcinogenic risk from heavy metals and the high detected levels of As and Cd is required.