In the past decade, episodes of severe air pollution, known as the “black cloud,” have occurred in Cairo, Egypt, in the early autumn. In this study, data from the Moderate Resolution Imaging Spectrometer (MODIS) and the Multi‐angle Imaging Spectroradiometer (MISR) are used with meteorological data and trajectory analyses to determine the cause of these events. MODIS fire counts put the source as the burning of agricultural waste after harvest season in the Nile delta region. Synchronous MISR data show that these fires create low altitude (<500 m) plumes of smoke and aerosols which flow over Cairo in a few hours, as confirmed by Hybrid Single‐Particle Lagrangian Integrated Trajectory (HYSPLIT) forward trajectory analyses. Much of the burning occurs at night, when an inversion constrains the plumes to remain in the boundary layer (BL). Convection during the day raises the BL, dispersing these smoke particles until the next night.

The monthly climatology of Multi-angle Imaging SpectroRadiometer (MISR) data show that the aerosols during the black cloud periods are spherical with a higher percentage of small and medium size particles, whereas the spring aerosols are mostly large non-spherical particles. All of the results show that the air quality in Cairo and the Nile delta region is subject to a complex mixture of air pollution types, especially in the fall season, when biomass burning contributes to a background of urban pollution and desert dust.

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Egypt suffers from freshwater crisis, and the shortage is predicted to become severe by 2025. Egypt is exposed to flash floods, especially in Sinai governorate, causing rapid rises of water in a short amount of time and can trigger other catastrophic hazards associated with damage, danger to human life, properties and environment. Flash floods may be considered a source of water that can be explored to meet the water shortage problem. In this study, a composite flash floods vulnerability index based on an integrated hydro-climatic and physical vulnerability component was created. The composite index was based on eight parameters including rainfall distribution, elevation and slope, flow direction, streams, geomorphological features, soil type and land cover. The composite index was ranked into three categories: high, moderate and low. The index can help identify the weak and strong points to support the decision-making process concerned with water management as an essential prerequisite for Egypt sustainable development. The results revealed that the urban, vegetation cover, loamy sand, sand dunes, the low elevation and the flat areas are the most affected by the flash floods in EL-Arish City in Sinai governorate. 42% of Wadi El-Arish had low vulnerability, 45% moderate vulnerability and 13% high vulnerability.