At the end of December 2019, the rapid spread of the COVID-19 (SARS-CoV-2) disease and, subsequently, deaths around the world, lead to the declaration of the pandemic situation in the world. At the ...beginning of the epidemic, much attention is paid to person-to-person transmission, disinfection of virus-contaminated surfaces, and social distancing. However, there is much debate about the routes of disease transmission, including airborne transmission, so it is important to elucidate the exact route of transmission of the COVID-19 disease. To this end, the first systematic review study was conducted to comprehensively search all databases to collect studies on airborne transmission of SARS-CoV-2 in indoor air environments. In total, 14 relevant and eligible studies were included. Based on the findings, there is a great possibility of airborne transmission of SARS-CoV-2 in indoor air environments. Therefore, some procedures are presented such as improving ventilation, especially in hospitals and crowded places, and observing the interpersonal distance of more than 2 m so that experts in indoor air quality consider them to improve the indoor air environments. Finally, in addition to the recommendations of the centers and official authorities such as hand washing and observing social distancing, the route of air transmission should also be considered to further protect health personnel, patients in hospitals, and the public in other Public Buildings.
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•The SR was conducted to compile studies on airborne transmission of virus in indoor air.•In total, 14 relevant and eligible studies were included.•There is a great possibility of airborne transmission of SARS-CoV-2 in indoor air.•Improving ventilation is essential, especially in hospitals and crowded places.
Recently, an outbreak of a novel human coronavirus which is referred to as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (COVID-19) by the World Health Organization (WHO) was ...identified in Wuhan, China. To help combat the pandemic, a systematic review (SR) was performed to collect all available studies concerning inactivation methods, environmental survival, and control and prevention strategies. A comprehensive literature survey yielded 42 eligible studies which included in the SR. The results confirmed that the WHO recommended two alcohol-based hand rub formulations (ethanol 70–95% and 2-propanol 70–100%) had an efficient virucidal activity in less than 60 s by more and equal 4 log
10
(≥ 99.99) approximately and could be used for disinfection in public health and health-care facilities. The findings indicated that SARS-CoV-1 and SARS-CoV-2 can survive under different environmental conditions between 4 and 72 h approximately. The results also demonstrate that temperature and relative humidity are important factors in the survival of SARS-CoV-2. The main strategies recommended by the WHO to avoid contracting SARS-CoV-2 are hand washing several times in the day and maintaining social distancing with others. It is important to note that the more studies require addressing, the more possible airborne transmission due to the survival of SARS-CoV-2 in aerosols for 3 h approximately. We hope that the results of the present SR can help researchers, health decision-makers, policy-makers, and people for understanding and taking the proper behavior to control and prevent further spread of SARS-CoV-2.
Abstract
In this research, the photocatalytic removal of reactive blue 19 (RB19) dye is investigated employing zinc oxide/cerium (ZnO@Ce) nanoparticles decorated with biochar under LED irradiation. ...Synthesis of ZnO@Ce nanoparticles decorated with biochar was performed utilizing the co-precipitation procedure and, then, the texture and morphology of the fabricated nanocomposite were analyzed using energy dispersive X-ray (EDX), field emission scanning electron microscopy (FE-SEM), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET), and Fourier transform infrared (FTIR) spectroscopy techniques. Moreover, FE-SEM images demonstrate that ZnO–Ce nanoparticles were successfully decorated on the surface of biochar. The specific surface areas of biochar and biochar/ZnO–Ce were 519.75 and 636.52 m
2
/g, respectively. To achieve the maximum yield in the removal of RB19 dye, the effects of operating variables including dye concentration, LED lamp power, biochar@ZnO–Ce catalyst dose, pH and H
2
O
2
dose were explored. Besides, the maximum percentage of RB19 dye removal was 96.47% under optimal conditions, i.e. catalyst dosage of 100 mg, H
2
O
2
dosage of 1 mL, pH of 9, initial dye concentration of 5 ppm, LED power of 50 W, and reaction time of 140 min. Furthermore, the kinetic analysis reveals that the removal of RB19 dye follows the pseudo-first order kinetic model, with calculated values of a reaction rate constant of 0.045 min
−1
and a correlation coefficient of R
2
= 0.99, respectively. Moreover, the reusability and recyclability of biochar@ZnO/Ce nanocatalyst was promising over five runs, with only a 6.08% decrease in RB19 dye removal efficiency. Therefore, it can be concluded that the biochar @ZnO/Ce photocatalyst can be promisingly applied for the removal of azo dyes in aqueous solutions.
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•Diclofenac (DCF) is widely used to control pain and inflammatory disorders.•The first systematic review on the impacts of DCF side effects was conducted.•A literature search led to ...the identification of 14,862 results, 68 of which met our criteria.•There is a strong relationship between OS and DCF-induced DNA damage.•There is limited evidence of association between DCF and potential for estrogenicity.
Diclofenac (DCF) is a common non-steroidal anti-inflammatory drug (NSAID) that is widely used to control pain and inflammation. There has been much debate about detrimental effects of micro-pollutant such as DCF in non-target organisms. Therefore, the present systematic review (SR) evaluates the possible oxidative stress (OS) and DNA damage induced in DCF-exposed non-target organisms in aquatic environment. A systematic search was conducted in five international literature databases from 1970 to 2021. A comprehensive literature search led to the identification of 14,862 hits, 68 of which met our inclusion criteria. These studies encompassed a wide range of biological endpoints, including OS, DNA damage, cyto-genotoxicity, apoptosis, and estrogenicity potential in non-target organisms. The time, route and types of exposure to DCF was evaluated. There is a strong relationship between DCF exposure and OS, cyto-genotoxicity and DNA damage. Furthermore, there is limited evidence for estrogenic potential of DCF. According to the results of the studies considered in this work, it can be concluded that there is definitive evidence of DCF-induced OS, cyto-genotoxicity and DNA damage on the various types of non-target organisms due to the chronic exposure to DCF. The biomarkers were used to assess adverse consequences and could be used as an early warning signal for environmental monitoring of the presence of pharmaceuticals in aquatic environments. Due to the definitive evidence provided for adverse effects of DCF and multimodel mechanisms of action, it is essential to take a degree of caution to use the DCF and develop the advanced treatment technologies to prevent the release of this type of contaminant to aquatic environments.
Microplastics (MPs), the emerging contaminants of the present century, are potentially a major threat to human health and ecology. There is currently no comparison of the properties of MPs in indoor ...and outdoor air. Thus, there is a need a systematic review (SR). The goals of this study were to answer the following questions: (1) what are the geographical distribution, sources, abundances, and characteristics (polymer, type, shape, color, size) of MPs in outdoor and indoor air? (2) What are the limitations of the published studies and recommendations for future research? To achieve these objectives, four electronic databases were searched to find works published before December 31, 2022. In total, 37 publications were selected based on the PRISMA guidelines. The study found that polyester and polyethylene terephthalate were the most dominant polymer types in outdoor and indoor environments, respectively. The most important indoor sources for MPs included synthetic textiles, kitchen plastic utensils, synthetic fiber carpets, detergents, and furniture, while the most important sources for outdoor MPs include industrial emissions, particulate emissions from vehicles, burning of plastic waste, the expulsion of air bubbles and wave action in ocean and decomposition and destruction of plastic materials. Fibers were the dominant shape of airborne MPs in both environments. The predominant colors of the MPs in samples of the indoor air were white and transparent, whereas black was most abundant in the microplastic samples collected from the air outside the building. Finally, given the ubiquitous nature of MPs and their potential for adverse effects, governments should take effective measures to reduce the production of plastic materials and finally increase plastics reuse, and recycling rate.
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•MPs as an emerging pollutants in indoor and outdoor air were systematically studied.•The geographical distributions, sources, abundances, and characteristics of MPs were studied.•To survey MPs, 37 publications were selected based on the PRISMA guidelines.•Polyester and PET were the most dominant polymer types in both air environments.•Fibers were the dominant shape of airborne MPs in both environments.
In December 2019, all nations learnt about the emergence of a pandemic of coronavirus disease (COVID-19), induced by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is a ...member of the β-coronavirus group. As
SARS-CoV-2
has the potentiality of leading to life-threatening respiratory failure, its transmission routes need to be characterized. Yet
, the possibility of airborne transmission is still debated. This study was performed to evaluate potential hospital indoor air viral quality in order to detect SARS-COV-2. For this purpose, an impinger method was used to monitor the SARS-COV-2 virus in the air. Thus, 33 samples were collected from 8 different hospital locations. The sampling time was between 50 and 60 min with a sampling flow rate of 28 L/min. Air samples were taken from 2 to 5 m away from the patients’ beds. Temperature, relative humidity, and CO
2
concentration were 28, 37, and 438 ppm, respectively. The results indicated that air samples which were 2 to 5 m away from the patients’ beds were negative for the presence of the virus. According to the obtained results, it is suggested that airborne transmission may not have much effect on this pandemic. However, as the patients with SARS-CoV-2 were hospitalized in rooms with negative air pressure, the results might have been negatively affected.
Graphical abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease started in late 2019 and still continues as a global pandemic, spreading among people around the world. There is limited knowledge ...about the role of contaminated environmental surfaces, especially high-touch public surfaces, in the transmission of the disease. The objective of the present investigation was detection of different variants (Delta, UK, and Omicron) of SARS-CoV-2 RNA (genome) on inanimate surfaces in high-touch public environmental surfaces in different seasons. Automated teller machines of banks (ATM), point-of-sale (POS) machine, gas station pump nozzles, and escalator handrails of malls were selected as high-touch environmental surfaces in public places. Overall, 75 samples were collected from these places and examined for the presence of SARS-CoV-2 RNA (genome), and 21 samples (28%) were positive. Although the role of fomite transmission of COVID-19 is understood, more studies should be conducted to determine the virus survival rate as well as the required efforts to prevent the spread of SARS-CoV-2 such as frequent cleaning and the use of efficient disinfectants on environmental surfaces, especially high-touch public places. In conclusion, the results address the importance of touching contaminated inanimate objects as well as transmission through environmental surfaces, and they could be used to establish an effective protocol to prevent indirect environmental transmission of SARS-CoV-2, slow down the spread of the virus, and reduce the risk of infection.
TiO
2
–FeZn nanocatalyst combined with sonolysis were used to activate peroxymonosulfate (PMS) as a highly efficient advanced oxidation process (US/TiO
2
–FeZn/PMS) for the decoloration of orange II ...dye (OII) and real textile wastewater. The characterization of the as-synthesized NPs was performed by SEM, FTIR, EDX and XRD analyses. Optimal experimental conditions of operational parameters were obtained: pH = 3, 15 mg/L initial OII concentration, 0.2 g/L PMS, 0.7 g/L nanocatalyst dosing, and 300 W ultrasonic power. The decolorization was observed to increase with increasing the dose of nanocatalyst and the ultrasonic power, and with decreasing pH (under acidic conditions). Under optimal experimental conditions, decolorization and COD removal of textile wastewater were 99.9% and 74.6%, respectively, at 40 min. The TiO
2
–FeZn/PMS/US as a novel process exhibited a higher removal of OII (95%) than TiO
2
NPs/PMS/US process (54%). The OII removal efficiency by the different processes decreased in the following order: TiO
2
–FeZn/US/PMS > TiO
2
–FeZn/PMS > TiO
2
–FeZn/US > TiO
2
/US/PMS > US/PMS > TiO
2
–FeZn > PMS > US. The recyclability study revealed that the process could be reused up to three consecutive cycles. The current US/nanocatalyst/PMS system was concluded to be an efficient, reusable and stable nanocatalyst for the oxidation of textile dyes.
Background: Nanocomposites have received remarkable attention as effective adsorbents for removal of coexisting pollutants over the last decades. The presence of heavy metals (HMs) in wastewater has ...caused a global health concern. Therefore, the aim of this study was to review the most relevant publications reporting the use of nanostructures to simultaneous adsorption of HMs in mixed aqueous systems. Methods: In this systematic review, 9 studies were included through a systematic search in the three databases (ISI, Scopus, and PubMed) during 1990-2021. The optimal value of simultaneous adsorption parameters such as initial concentration, contact time, adsorbent dosage, and pH was discussed. Results: Findings indicate that the Langmuir and Freundlich models and the pseudo-second-order kinetic model have been widely used and the most popular models to describe the equilibrium of HMs by nanoadsorbents. This study confirmed that the simultaneous removal rate of HMs decreased with an increase in pH value. It was found that the major mechanisms of HMs adsorption onto nanostructures were electrostatic interactions and precipitation. Conclusion: Nanocomposites have remarkable adsorption performance for HMs with the highest adsorption capacity (qe(mg/g)).
Background: The occurrence of COVID-19 as a public health emergency of international alarm was declared by the World Health Organization (WHO) on January 30, 2020. The identified transmission path is ...due to direct close contact or via respirational droplets. There is uncertainty about other ways, such as transmission of surfaces, air, and other sources. This study follows the preferred reporting items for systematic reviews and meta-analysis guidelines to investigate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in environmental surfaces, water, wastewater, and air. Materials and Methods: In this study, we performed a systematic literature search in PubMed (MEDLINE), Scopus, and Web of Science (ISI) databases in August 2022. The investigation on electronic databases resulted in a total of 2049 articles. A total of 249 potentially relevant were identified for full-text evaluation. Meanwhile, 30 articles were included in the synthesis. Results: According to four included studies, negative detection of SARS-CoV-2 transmission in water is established. A laboratory study has shown that viable SARS-CoV-2 could be found in aerosols for about 3 h. Also, the virus can be found on dry surfaces, depending on the material of the surface, for 8 to 72 h. Our results showed it is possible to exciting SARS-CoVs in air, environmental surface, and wastewater. Conclusion: These results can help healthy policymakers make suitable assessments of main prevention measures.
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