RIYADH — The precautionary and preventive measures to prevent the spread of coronavirus and the enforcement of curfew have contributed to bringing down the level of air pollution to a great extent in the capital city of Riyadh. The lockdown and the subsequent suspension of some industrial activities and vehicular movement in the city have resulted in reducing the concentration of pollutants by a large percentage, as recorded by some 17 air quality monitoring stations located throughout the city, the Saudi Press Agency reported. Air quality monitoring stations under the Royal Commission for Riyadh recorded a noticeable decrease in a number of gaseous air pollutants such as Nitrogen Dioxide (NO2) by 60 percent, Sulfur dioxide (SO2) by 40 percent, and Carbon monoxide (CO) by 56 percent. The stations also recorded a fall in Hydrogen Sulfide (H2S) by 38 percent, and the results concluded that the Air Quality Index (AQI) in Riyadh for gas pollutants is currently at an excellent and very good level. The air monitoring stations contain devices that measure the concentration of 10 specific pollutants, which show instantaneous concentration data for the major pollutants. In addition, these stations monitor climate information such as wind speed and direction, as well as the amount of rain and temperatures in Riyadh, relative humidity and solar radiation. A special application for the air quality management program has been set up under the name of “Riyadh Air Quality”, and the app displays the AQI in Arabic and English on the level of suspended particles and gases every hour for the area surrounding each station. It is noteworthy that the air quality management program comes within the framework of the Royal Commission for Riyadh’s concern for the environment. The commission monitors ambient air quality within neighborhoods, as well as along roads and outside the urban area. The program contributes mainly and effectively to taking the appropriate decision to reduce the effects of air pollutant sources and improve their levels.