UAlbany researchers Dr. Shedrack Nayebare, Dr. David Carpenter, Dr. Mirza Hussain, and Dr. Haider Khwaja recently studied air quality in the holy city of Makkah, Saudi Arabia with a team of researchers from King Abdulaziz University, Hamad Bin Khalifa University, and Umm Ul Qura University; the resulting publication can be found in the December 2018 Environmental Pollution.
Located in a hilly region of Saudi Arabia, Makkah has many tunnels that increase the air pollution in the area. With over 4 million Muslim pilgrims visiting annually, the holy city sees high use of public transportation and consumption of gasoline, along with high levels of resuspended dust. In addition, neighboring cities such as Jeddah, Rabigh, and Yanbu are heavily industrialized, meaning that the industrial emissions from these locations can be carried by wind into Makkah. This makes air pollution a critical problem in the city – especially since air pollutants remain airborne longer than in other countries due to Saudi Arabia’s climate, which can be described as semi-arid to arid.
This study examined fine particulate matter (PM2.5) from five sampling sites in Makkah from February 2014 to January 2015. These sites represented both residential and urban/semi-industrial areas to create a balanced estimate of air pollution levels.
For the majority of the study period, the air quality was determined to be unhealthy to hazardous. The researchers found that the average 24-hour PM2.5 levels far exceed the World Health Organization’s air quality guideline and 99 percent of the daily levels exceeded this guideline. Higher levels of pollution were seen in the spring and summer, perhaps due to a lower atmospheric boundary layer reducing the dispersion of pollutants. A major source of pollution may be long-distance and regional transport of PM2.5 as shown by backward-in-time wind trajectories. More than 75 percent of PM2.5 emissions were due to human activity, such as vehicular emissions, fossil fuels and oil combustion, and industrial dust.
This study builds on previous literature that shows the growing problem of air pollution in Saudi Arabia. It was not conducted during the annual pilgrimage which results in the most visitors to Makkah, meaning that air pollution problems are most likely further increased during this time. Since the majority of emissions were due to anthropogenic sources, establishing and implementing regulations on sources of air pollution is critical to protect the health of Saudi Arabians, especially since long-distance travel of air pollutants means that the poor air quality is having more than just a local impact.