Monitoring Pollution and Air Quality of Pedestrian and Automotive Tunnels in the City of Makkah

Millions of Muslims annually gather in the holy city of Makkah for annual pilgrimage (HAJJ) and use pedestrian and automotive tunnels to move from one place to another. These tunnels generally use open-loop air circulation systems to maintain air impurities inside the tunnel within acceptable limits. Due to overcrowding and congestion, the amount of time pilgrims spend crossing the tunnel grows drastically, revealing people to hazardous vehicular emissions like volatile organic compounds (VOCs), Sulphur oxides, carbon oxides (CO and CO
₂
) together with fine dust (PM10) and high humidity levels. Moreover, an accident or a ventilation breakdown can expose pedestrians and open vehicles/motorcyclists to high levels of harmful gases. This study presents a monitoring and control system employing internet of things (IoT) to monitor air quality and pollution of long tunnels with predictive analysis and data analytics-based reporting for municipal authorities. Specialized sensors are deployed at predetermined locations in a tunnel together with base-station nodes. These sensor nodes upload collected data to the cloud which is then stored and processed for generating reports and for advising actions to be taken, queries and alert mechanisms. This system controls tunnel aeration and ventilation systems based on some set-points for several pollutants. It alerts the tunnel users via e-notice boards when air pollutants reach alarming levels. Furthermore, the system recommends countermeasures needed to be taken like evacuation information and emergency exits. It is also able to detect fire hazards, smoke, ventilation breakdown and accidents, alerting the authorities to take actions without human involvement.