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.

Artificial turf or synthetic grass releases hazardous substances such as heavy metals, polycyclic aromatic hydrocarbons (PAHs), and volatile organic compounds (VOCs). The current study aimed to evaluate the concentration levels of hazardous substances that are emitted from artificial turf as a result of sunlight effect; and to assess the expected exposure risks to such emitted substances during various activities. The current study aimed to evaluate the concentration levels of hazardous substances that are emitted from artificial turf as a result of the effect of sunlight. And to assess the expected risks of exposure to these substances emitted during the various activities. VOCs emitted from artificial turf samples were monitored and collected in the ambient air of three football fields, the ambient air around a piece of new artificial turf that has not yet been used on playing fields, but has been exposed to sunlight within one year and in the indoor air around a piece of new artificial turf. Which has not yet been used on the playgrounds and was placed at room temperature and away from sunlight. The current study shows that average afternoon morning VOCs levels were 277, 333, 405 and 509 mg/m³ in winter, autumn, spring and summer, respectively. The most predominant PAHs compounds present in the samples were compounds with 3-rings and 4-rings. The average daily intake (ADI) for three exposure routes (ingestion, inhalation, and dermal contact) was calculated for different age categories (3–6, 7–15, 16–18, 19–22, 23–55, and 56–70 year). Non-Carcinogenic exposure risk as hazard quotient (HQ) and hazard index (HI) were detected. All HI values were 3–6 years.

Dust deposited on leaves of trees can be effectively used as monitors of polycyclic aromatic hydrocarbons (PAHs). Sixteen EPA priority PAHs concentrations in deposited dust on leaves of the street trees (leaves dust) at 14 sampling sites at traffic and residential areas in Cairo, Egypt were measured. The health risk of the 16 PAHs to humans were estimated and calculated. Results indicate that the predominant PAHs were high molecular weight-PAHs, with higher contribution 83%, whereas low molecular weight-PAHs were the less lower contribution 17%. Higher concentrations of ΣPAHs recorded at traffic areas (18,223 ± 4,172) mg/kg, whereas lower levels were found in residential areas (8,261 ± 2,006) mg/kg. The diagnostic ratios and total indexes of PAHs compounds indicate that traffic emissions and incomplete combustion were the major sources of PAHs in deposited dusts on leaves of street trees of Greater Cairo. The health risk assessment focused on ΣPAHs in leave dust, which were related to health impacts. The results recorded higher exposure doses at traffic areas than residential areas. In the current study, hazard quotient and hazard indices values were less than 1 at all sampling sites, indicating that there were no health effects for noncarcinogen. The cancer risk values for inhalation of PAHs in traffic areas > residential areas for child and adult. The current results showed that the cancer risk values were within the safe levels set by United States Environmental Protection Agency. These results indicate that cancer risk values for Greater Cairo were within the acceptable range, implying negligible carcinogenic risk.