Air pollution from vehicles in Makkah, Saudi Arabia: Challenges and sustainable solutions

Abstract. Makkah, a religious city in Saudi Arabia, confronts significant air pollution issues due to the influx of millions of visitors, especially during the Hajj and Ramadan seasons. The study reviewed a few published reports and journals and obtained data from various sources: hourly traffic flow on six major roads during the Hajj season, PM10 and PM2.5 levels from two air quality stations, meteorological parameters (such as, air moisture, wind, its direction, temperature) and an emission inventory for industries. Using this data, the dispersion and impact of PM from automobile emissions were assessed in the study area. The results showed that PM10 and PM2.5 exceed the air quality limit often, and vehicular emissions were a major source of air pollution in the city, both light-duty and heavy-duty vehicles, which is compounded by the large number of tourists during the Hajj and Ramadan seasons. Pollutants causing respiratory and cardiovascular problems consist of volatile organic chemicals (VOCs), carbon dioxide (CO2), nitrogen oxides (NOX), and sulfur dioxide (SO2) etc. They also pose a threat to public health. Although the study cannot identify certain trends over time, it does show that Makkah has persistent and complex air pollution issues, emphasizing the necessity for efficient remedies and regulations to address the issues of the environment and public health. To mitigate the impact of automobile-related air pollution on the environment and human health in Makkah, some sustainable solutions include the development of public transportation, vehicle emission standards, electrical vehicles, cleaner fuels, and so on.