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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 (PM2.5) sampled in an urban area of Greater Cairo during 2017–2018 was studied. The PM2.5 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. PM2.5 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 PM2.5 physico-chemical properties in the area of study might be useful for planning future strategies aiming to improve air quality and lower health hazards.

The present study aimed to find a beneficial solution for waste recycling and disposal by converting it from an environmental load to products useful for air pollution control.

Data dealing with polycyclic aromatic hydrocarbons (PAHs) levels in settled dust of Greater Cairo houses (GCH), Egypt, and their implication on human health risk are scarce. The goal of this study was to gain insights into the characterisations of PAHs in settled dust in GCH and their associated carcinogenic and mutagenic risks. ƩPAH concentrations were 3125 and 268 ng/g in settled dust in GCH and rural houses (RH), respectively. Heavier congeners (4–6 aromatic ring PAHs) represented 86.5% (GCH) and 92% (RH) of ƩPAHs. Houses on main streets are exposed to higher levels of PAHs than those on the side streets. The main sources of PAHs in GCH and RH were vehicular emissions (pyrogenic sources) and PAHs in GCH come from local emissions and in RH from the surrounding urban cities. Results showed that the carcinogenicity of PAHs associated with dust exceeds their mutagenicity. Based on Incremental Lifetime Cancer Risk (ILCR) estimations, the order of cancer risk (CR) was as follows: urban houses (UH) > suburban houses (SUH) > RH. CR and ILCRs calculations suggest that children and adults exposed to settled dust-bound PAHs in GCH and RH have an increase in CR, as CR and ILCRs values exceeded accepted levels.