Elham Farouk Mohamed

Air pollution by microplastics (MPs) is an increasingly concerning environmental issue, but the presence of MPs in the atmosphere and its potential health risks has not been studied in Greater Cairo. The sites were therefore selected during the winter season from the north to the south of the Cairo metropolitan area, representing urban and residential/industrial areas in terms of population, traffic, and industrial pressure. This was achieved through a combination of quantitative MP detection, mathematical modeling, and a risk assessment approach based on total suspended particulate matter (TSP) at these sites. The TSP concentration was investigated in the air and associated MP particles. The highest MP values were found at the study sites with higher population and more traffic than at lower locations. The spatial distribution of site concentrations was from high to low. Helwan site (87 particles/m³) had the most MP, followed by Dokki (69 particles/m³) and Nasr City (60 particles/m³), and El-Nozha had the least MP during the investigation (30 particles/m³). The morphology, composition, and size of these MPs in the samples were determined by scanning electron microscopy (SEM) and gas chromatography–mass spectrometry (GC–MS). Various MP forms have been identified in these sites, including fibers, fragments, films, and pellets, with fragments being the most common. Three different MP polymers (PE, PP, and PS) were identified. The potential health risks posed by airborne MPs cannot be ignored when exposed to outdoor airborne substances at maximum annual levels. This study confirms the widespread existence of the inhaled MP in the air and provides a solid basis for future studies aimed at understanding real-world conditions of inhalation exposure to MP. Graphical abstract

Climate change due to the air pollution is actually one of the largest environmental challenges worldwide. Preparation and development of stable and highly efficient nanocomposite membranes remain a significant goal because of its enormous importance of controlling the environment. This study investigated a simple synthesis of poly (vinyl alcohol)/graphene oxide (PVA/GO) nanocomposite membrane for air pollutant remediation. The chemical and physical structures, morphologies, and conductivities were investigated as a function of the GO loading. The objective of the present study was to evaluate the efficiency of novel PVA/GO membranes in the removal of both formaldehyde (FA) as a pollutant VOCs model and SO₂ as a model of greenhouse gases. Furthermore, the purpose of this study is to identify good predictors for selecting the appropriate optimal GO content in GO/PVA nanocomposites that exhibit higher air pollutant removal performance as well as design an economical GO/PVA nanocomposite air purification system for removal of the air pollutants in the field. To our knowledge, field application of GO/PVA nanocomposite volatile organic compound (VOCS) filters and control of SO₂ gas pollutants from indoor air has not yet been realized. The nanocomposite membranes with an optimum GO content exhibited higher removal performance for the FA gas pollutant, this enhancement reached 90% in the laboratory scale. However, during the application in the field, it showed 75% FA removed from the indoor air. These new nano-membranes reveal also wide efficiencies of SO₂ removal (80%) when applied in the field. Therefore, this filter system proved an excellent efficacy in the removal of air pollutants and could be more promising in various industrial applications.

Volatile organic compounds (VOCs) include different organic chemicals that can be easily vaporized and transported long distances via the environment. VOCs and health effects are dependent on the type, concentrations and duration of exposure. Chlorinated volatile compounds (CVOCs) are the most toxic VOCs because of their potential to cause cancer in humans. Many CVOCs are present in significant amounts in our ecosystems, including air, water and soil, and are resistant to degrade, despite the fact that their use has recently been more carefully managed and restricted. These chlorinated compounds are highly toxic and numerous have been banned from commercial utilization because they are persistent in the environment and accumulate in biological systems. Although these chemicals have been banned for decades, they are still being measured in the environment and the food chain. This paper provides a comprehensive review of the recent applications of biotechnology and nanotechnology in CVOCs remediation in various environmental systems. It is divided into many sections; each focuses on specific subtopics, covering diverse perspectives on the principal topic. Sections presented in the paper include; occurrence of CVOCs in the environment, sources, potential human health effects, recent biotechnology and nanotechnology used for CVOCs remediation, advantages and disadvantages of each strategy of treatment and future perspectives in this aspect are also provided. Finally, this paper presents advanced technologies available, to remind CVOCs emissions with their relative merits and demerits, better understand this integrated technology, and to effectively apply them in air, soil, and groundwater remediation. Consequently, we hope that this paper will guide and inspire the application of biotechnology and nanotechnology to the remediation of CVOCs.

Greater Cairo (Egypt) is a megalopolis where the studies of the air pollution events are of extremely high relevance, for the geographical-climatological aspects, the anthropogenic emissions and the health impact. While preliminary studies on the particulate matter (PM) chemical composition in Greater Cairo have been performed, no data are yet available on the PM’s toxicity. In this work, the in vitro toxicity of the fine PM (PM_2.5) sampled in an urban area of Greater Cairo during 2017–2018 was studied. The PM_2.5 samples collected during spring, summer, autumn and winter were preliminary characterized to determine the concentrations of ionic species, elements and organic PM (Polycyclic Aromatic Hydrocarbons, PAHs). After particle extraction from filters, the cytotoxic and pro-inflammatory effects were evaluated in human lung A549 cells. The results showed that particles collected during the colder seasons mainly induced the xenobiotic metabolizing system and the consequent antioxidant and pro-inflammatory cytokine release responses. Biological events positively correlated to PAHs and metals representative of a combustion-derived pollution. PM_2.5 from the warmer seasons displayed a direct effect on cell cycle progression, suggesting possible genotoxic effects. In conclusion, a correlation between the biological effects and PM_2.5 physico-chemical properties in the area of study might be useful for planning future strategies aiming to improve air quality and lower health hazards.