This study aims to analyze the correlation between the daily confirmed COVID-19 cases in Jordan and metrological parameters including the average daily temperature (°C), maximum ambient temperature (°C), relative humidity (%), wind speed (m/s), pressure (kPa), and average daily solar radiation (W/m²). This covers the first and the second waves in Jordan. The data were obtained from both the Jordanian Ministry of health and the Jordan Metrological Department. In this work, the Spearman correlation test was used for data analysis, since the normality assumption was not fulfilled. It was found that the most effective weather parameters on the active cases of COVID-19 in the initial wave transmission was the average daily solar radiation (r = − 0.503; p = 0.000), while all other tests for other parameters failed. In the second wave of COVID-19 transmission, it was found that the most effective weather parameter on the active cases of COVID-19 was the maximum temperature (r = 0.394; p = 0.028). This was followed by wind speed (r = 0.477; p = 0.007), pressure (r = − 0.429; p = 0.016), and average daily solar radiation (r = − 0.757; p = 0.000). Furthermore, the independent variable importance of multilayer perceptron showed that wind speed has a direct relationship with active cases. Conversely, areas characterized by low values of pressure and daily solar radiation exposure have a high rate of infection. Finally, a global sensitivity analysis using Sobol analysis showed that daily solar radiation has a high rate of active cases that support the virus’ survival in both wave transmissions.

This study was designed to investigate the impact of meteorological indicators (temperature, rainfall, and humidity) on total COVID-19 cases in Pakistan, its provinces, and administrative units from March 10, 2020, to August 25, 2020. The correlation analysis showed that COVID-19 cases and temperature showed a positive correlation. It implies that the increase in COVID-19 cases was reported due to an increase in the temperature in Pakistan, its provinces, and administrative units. The generalized Poisson regression showed that the rise in the expected log count of COVID-19 cases was 0.024 times for a 1 °C rise in the average temperature in Pakistan. Second, the correlation between rainfall and COVID-19 cases was negative in Pakistan. However, the regression coefficient between the expected log count of COVID-19 cases and rainfall was insignificant in Pakistan. Third, the correlation between humidity and the total COVID-19 cases was negative, which implies that the increase in humidity is beneficial to stop the transmission of COVID-19 in Pakistan, its provinces, and administrative units. The reduction in the expected log count of COVID-19 cases was 0.008 times for a 1% increase in the humidity per day in Pakistan. However, humidity and COVID-19 cases were positively correlated in Sindh province. It is required to create awareness among the general population, and the government should include the causes, symptoms, and precautions in the educational syllabus. Moreover, people should adopt the habit of hand wash, social distancing, personal hygiene, mask-wearing, and the use of hand sanitizers to control the COVID-19.

Two compositions of graphene oxide-magnetite nanocomposites were studied as catalysts in the heterogeneous Fenton process. Transmission electron microscopy and X-ray diffraction revealed that the graphene oxide sheets were covered with nanoparticles of magnetite, with an average crystallite size of 7 nm. Infrared spectroscopy analysis indicated that the phases interacted through covalent Fe-O-C bonds. The composites presented significantly improved catalytic activity, compared to pure magnetite, with a synergistic effect of up to a factor of 17.1 for the Fenton degradation of caffeine, achieving total removal after 90 min. This synergistic effect was a consequence of the interaction between the phases, resulting in improved mass transfer of caffeine to the catalyst surface, adsorption and efficient degradation, with enhanced HO• generation. The surface reaction constant increased by up to three orders of magnitude, demonstrating the important role of graphene oxide in the degradation kinetics of the heterogeneous Fenton process. The surface-bonded hydroxyl radicals were responsible for caffeine degradation, achieving 9.4 μmol L⁻¹. After five degradation cycles, a loss of Fe-O-C bonds and increase in oxygenated groups were associated with a small decrease of caffeine removal efficiency, from 98 to 82%, without significant iron leaching, in the dark, and with low consumption of hydrogen peroxide.

The main objective of this work is to use soybean hull (SBH) waste as an adsorbent for the removal of two industrial textile dyes: Reactive Blue 21 (RB21) and Reactive Yellow 145 (RY145). Physical characterization of SBH and kinetic and equilibrium experiments were performed to determine the adsorption conditions. The best adsorption condition was pH 2.0 because the zero electrical charge of soybean hulls (pHZ = 0) is 5.27; thus, in an acidic pH, the adsorbent is positively charged, and the dyes keep their anionic charges due to the –SO₃⁻ and –OSO₃⁻ groups. Kinetic data were better represented by the Elovich kinetic model, evidencing two well-differentiated mass transfer regions, which agrees with a pseudo-second-order kinetic mechanism. The experimental data showed that RB21 and RY145 were fitted with Hill and Redlich–Peterson isotherm models, respectively. Consequently, the maximum adsorption capacities of SBH for RB21 and RY145 dyes were 149 mg/g and 87 mg/g, respectively. Dye adsorption in packed bed column was also assayed at different bed heights, flow rates, and inlet concentration of dyes. The Thomas, Yoon–Nelson, and modified dose-response (MDR) models fitted well to the breakthrough curves, the MDR model being the one with the highest correlation coefficients, with 96.5% and 94.4% removal of RY145 and RB21 dyes, respectively.

Direct or indirect discharge of wastes containing organic pollutants have contributed to the environmental pollution globally. Decontamination of highly polluted natural resources such as water using an effective treatment is a great challenge for public health and environmental protection. Photodegradation of organic pollutants using efficient photocatalyst has attracted extensive interest due to their stability, effectiveness towards degradation efficiency, energy, and cost efficiency. Among various photocatalysts, layered double hydroxides (LDHs) and their derivatives have shown great potential towards photodegradation of organic pollutants. Herein, we review the mechanism, key factors, and performance of LDHs and their derivatives for the photodegradation of organic pollutants. LDH-based photocatalysts are classified into three different categories namely unmodified LDHs, modified LDHs, and calcined LDHs. Each LDH category is reviewed separately in terms of their photodegradation efficiency and kinetics of degradation. In addition, the effect of photocatalyst dose, pH, and initial concentration of pollutant as well as photocatalytic mechanisms are also summarized. Lastly, the stability and reusability of different photocatalysts are discussed. Challenges related to modeling the LDHs and its derivatives are addressed in order to improve their functional capacity.

Due to excessive application of essential oils and scented products in spa salons during aromatherapy and massage sessions, the elevated concentration of total volatile organic compounds (TVOCs), particularly terpenes, which are known as secondary organic aerosol (SOA) precursors, is expected there. This study was aimed at determination of VOCs with a particular regard to terpenes in air samples collected in selected spa salons located in Northern Poland. Active air sampling was conducted before and after treatments. Samples were analyzed with the use of thermal desorption gas chromatography coupled with flame-ionization detector (TD-GC-FID) and mass spectrometer (TD-GC-MS). Obtained results allowed to characterize chemical composition of indoor air of spa salons and also to relate the dependence between applied essential oil and indoor air chemical composition. It has been proved that (i) spa salons are characterized by TVOC concentrations exceeding recommended values of 300–400 μg m⁻³ in most of examined cases, reaching up to several thousand of micrograms per cubic meter, (ii) TVOC concentration is strictly related to salon characteristics and carried out treatments, (iii) terpenes constitute a significant part of TVOCs present in spa indoor air, from 22 up to 86%, (iv) most commonly investigated terpenes in the literature (D-limonene, α-pinene, camphene, and linalool) were also determined at the highest concentration levels in this study and (v) VOC chemical composition is strictly dependent on the type of applied essential oils. On the basis of obtained results, it may be stated that extensive application of essential oils rich in terpenes can significantly alter indoor air chemistry of spa salons, thereby influencing health and well-being of employees working there. Graphical abstract

Though Pb(II) adsorption onto HA has been extensively studied, its kinetic and thermodynamic features are not fully understood. This work investigated the kinetic processes and isotherms of Pb(II) adsorption onto a humic acid (HA) derived from leonardite in an aqueous solution. The basic properties of the HA were determined by standard methods, and Fourier transform infrared spectroscopic (FTIR) technique. Adsorption kinetic experiments were conducted at 120 mg Pb/L at 288, 298, 308, and 318 K. The adsorption data were best fitted into the pseudo-second-order model, suggesting the chemisorption nature of Pb(II) adsorption. Batch adsorption experiments were conducted at 0–200 mg Pb/L, and the data fit the Freundlich and Temkin models well. Pb(II) adsorption onto HA initially increased, then decreased, with rising temperature. Thermodynamic parameters showed that Pb(II) adsorption was exothermic and spontaneous. Though Cu(II), Zn(II), or Cd(II) could compete with Pb(II) for adsorption, the low cost and high adsorption capacity of leonardite-derived HA determined that it was an excellent adsorbent to remove Pb(II) from an aqueous solution. The optimized experimental conditions derived from the central composite design (CCD) were 20 mg HA, pH 5.0, 4-h react time, and 80 mg Pb/L.

This study investigates the association between foreign direct investment (FDI) and environmental quality, taking into account policies and institutions for environmental sustainability across 23 sub-Saharan African (SSA) countries. We applied the Generalised Method of Moment (system-GMM) to analyse the data for the period 2005 to 2019. The results revealed that FDI improves environmental quality in the long run, whereas in the short run, FDI diminishes environmental quality when interacted with policies and institutions for environmental sustainability. Furthermore, policies and institutions for environmental sustainability and domestic investment improve environmental quality in both the long and short run. The study concludes that policies and institutions for environmental sustainability in SSA are important as they improve environmental quality. The study also finds policies and institutions for environmental sustainability complements with FDI to improve environmental quality in the long run. Finally, the study further establishes that domestic investment is important to improve environmental quality in SSA. The key findings call for strengthening policies for improving environmental quality in SSA.

To explore the relations between the number of accident deaths (NCD) and various factors in construction safety, a multiple linear regression model was established, based on the panel data of economy, construction labor, and the number of accident deaths in 31 provinces (regions) of China from 2009 to 2018. The results show that the average total profits and taxes (TPAT), and the death rate of ten thousand people (DR) are positively correlated with NCD, while the labor productivity (LP) is negatively correlated with it. Under the condition that other factors remain unchanged, NCD increases by 0.02 per a hundred million CNY. However, if DR increases by one ten thousand, NCD will increase by 8.66 on average. On the contrary, when LP increases by a hundred million CNY per ten thousand people, NCD decreases by 0.19. The model also predicts NCD in different provinces and cities from 2019 to 2020 with the method of quadratic exponential smoothing. As well, practice results show that the model is effective and practical.

Diazinon (DZN), a common organophosphorus insecticide (OPI), has hazardous effect to human and animals with its ubiquitous use. Considering the implication of reactive oxygen species (ROS) in the OPIs toxicity, the present study was aimed to evaluate the ameliorative properties of basil (BO) and sesame (SO) seed oils against the toxic effect of DZN. Forty adult male albino rats were divided into four experimental groups (n = 10 rats/group); control, DZN (10 mg/kg b.w/day), DZN + BO (5 ml/kg b.w/day), and DZN + SO (8 ml/kg b.w/day) groups, treated for a period of 4 weeks. DZN-exposed animals showed significant elevation in serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), and creatinine (Cr) with a significant decline in testosterone level compared with control. On the other hand, DZN + BO and DZN + SO groups revealed significant decreases in ALT, AST, BUN, and Cr with a significant increase in testosterone level when compared with DZN-exposed animals. Oxidative/antioxidant indices revealed significant increases of malondialdehyde (MDA) levels along with significant decreases of superoxide dismutase (SOD), glutathione peroxidase (Gpx), and catalase (CAT) activities among DZN-treated rats compared with control. Distinctly lower levels of MDA and increased activities of SOD, Gpx, and CAT were evident in both DZN + BO and DZN + SO groups when compared with DZN-exposed animals. Inflammatory and immuno-modulatory markers assessment showed a significant increase in TNF-α with a significant decline in IL-10 level in DZN group; meanwhile, both DZN + BO and DZN + SO groups revealed significant declines in levels of TNF-α with significant increases in IL-10. Corresponds immunohistochemistry, the total scores (TS) of TNF-α immunostainings in hepatorenal, testicular, and epididymal tissues of control, DZN + BO and DZN + SO groups were significantly lower than those values of DZN group. Additionally, the examined tissues of DZN + BO group revealed significant lower TS of TNF-α immunostaining compared with DZN + SO group. The overall data suggested that both BO and SO can be efficiently used as preventive herbal compounds against DZN-induced oxidative stress with special reference to their possible antioxidant, anti-inflammatory, and free radical activities. However, BO has more potent protective effect against DZN-induced tissue injury at both immunohistochemical and molecular levels.