In 2015, the renowned scientific journal Nature published a shocking study, which stated that approximately 3.3 million people worldwide die prematurely each year due to outdoor air pollution. Egypt had the 11^th highest death toll, with 35,000 deaths each year.

In 2010, Cairo ranked seventh among the world's deadliest cities for air pollution, with 6,000 premature deaths linked to outdoor air pollution each year. A large number of these deaths is caused by particulate matter.

One of the most important type of air pollutants is particulate matter. Particulate matter (PM) are microscopic solid or liquid particles that are suspended in the atmosphere. There are many types of particulate matter, classified according to physical characteristics: fumes, dust, smoke, ashes, mist, and spray. It has been reported that chronic exposure to particulate air pollutants is linked to heart disease, lung cancer and other respiratory illnesses.

In most parts of the world, the sources of particulate air pollutants are normally emissions from industry and motor vehicles. However, researchers estimate that 92 percent of pollution-related deaths in Egypt were linked to airborne desert dust. High concentrations of particulate air pollutants were reported across the entire Greater Cairo area, and researchers predict that this is due the arid climate, an almost constant northern wind which carries the dust and sand particles, and very low rainfall. Moreover, the topography of Cairo plays a major role in making the problem even worse: the city lies in a valley surrounded by hills, which hold the polluted air like water in a bowl.

The problem of particulate matter air pollution is a very serious one, and unfortunately, no clear plans have been put to solve it. The laws do exist, but the people are still not fully aware of the seriousness of the problem. Hopefully, new environmental initiatives will help make the situation better.

http://www.madamasr.com/en/2015/09/21/news/u/study-air-pollution-kills-35000-a-year-in-egypt-with-dust-the-biggest-culprit/

http://www.sciencedirect.com/science/article/pii/S209012321000007X?np=y&npKey=62c3c2ad3b78a427b929ab1a43d71c5d4ba8f3686e9df32e9496e49f80d9a374

https://earthdata.nasa.gov/user-resources/sensing-our-planet/a-black-cloud-over-cairo