Global air travel has increased tremendously in the last decade with easier domestic and intercontinental travel. People are more inclined towards the aeroplane for long-distance travel as it saves time as compared to other means of transport. An increase in Low-Cost Carriers (LCCs) makes air travel cheaper and more frequent. An increase in air travel tends to increase air pollution due to higher fuel consumption and exhaust emissions. According to the World Bank, 4.233 billion passengers globally travelled through aeroplanes. With the booming economy of aviation industries, more and more airports are being planned and constructed around the world. According to the CIA World Factbook (2016), there were 41,820 functioning airports in the world. The number has further increased in the past 5 years. The on-road transport vehicles contribute to the vehicular emission and have their fair share in the overall air pollution. But does the aviation industry contribute significantly to air pollution? Directly or indirectly?
Why is Airport Air Quality Monitoring necessary?
From the construction of an airport to a fully functioning airport there are numerous sources of air pollution. To start with, construction of the airport is in itself a huge project. An international airport or the major domestic airports have huge land requirements and undergo intense construction activities. The construction activities generate air particulate pollution whose monitoring and control are necessary as discussed here.
However, post-construction emissions are also significantly high that can cause potential threats to the civilians in the nearby vicinity. Airport air quality monitoring is crucial because the aircraft emissions during taxing, take-off and climb to 3000 feet generate air pollutants which affect the ground-level air pollution also known as boundary layer pollution. The Landing and Take-Off cycles (LTO) contributes maximum to the ambient air pollution. Ambient air quality is further deteriorated due to constant vehicular activities caused by taxis, buses, and private vehicles. The air pollution caused due to these activities greatly endangers the lives of people residing near the airport. Prolonged exposure to constant noise and air pollution causes both physical and mental illness which may turn into permanent damage.
Airports are also prone to fugitive dust emissions due to dust storms or long-distance dust dispersions. For regions near the desert, barren lands, with little vegetation, air particulate concentration tend to breach the ambient air quality standards which not only can be harmful to the passengers but also reduce the visibility resulting in riskier landing and take-off of airplanes.
Which pollutants to monitor?
Pollutants such as carbon monoxide (CO), unburnt hydrocarbons (UHC), nitrogen oxides, etc are the most common pollutants emitted from aeroplanes. All of them can cause significant respiratory diseases to human beings. The pollutants generate secondary pollutants such as smog if the meteorological conditions are adequate which directly affects visibility. Due to incomplete combustion during the near idle phase of the aircraft engine, CO and UHC are generated while during the maximum thrusts (take-off) highly toxic NOx is generated. These gases are capable of producing ground-level ozone which has detrimental effects on vegetation, animals, and humans. If there are other pollution sources such as busy roads, industries, or treatment plants near the airport, then specific pollutants should also be monitored such as formaldehyde, sulfur dioxide (SO2), particulate matter (PM), etc. With various studies emerging regarding indoor air quality, it is a rising concern for airports also.
Airport Air Quality Monitoring
The major source of air pollution is near the runways during taxiing and take-off of the aircraft. A network of ambient air quality monitoring devices is deployed near the runways and on the periphery of the airport. It is also necessary to monitor the nearby regions in the upwind and downwind directions of the airport as the pollutants can be easily dispersed due to high winds. For studies concerning only airport emissions, background air quality should be monitored near potential sources such as industries, residential areas, roads, etc. This helps in quantifying the contribution of airports in ambient air pollution and planning mitigative measures to curb it. In the case of major dust sources present near the airports, air particulate monitoring becomes mandatory.
Advantages of Smart Airports
With continuous airport air quality monitoring through devices like Oizom’s PolludroneTM and WeathercomTM automatic real-time decisions can be triggered. Runway utilization can be optimized based on the emissions of aircraft and ambient air quality regulatory limits. In the case of dust prone airports, automatic dust suppressors like mist cannons can be placed. Visibility monitoring helps in taking preventive measures. For example, if the visibility decreases beyond a lower limit set by the authorities, landing and taking off the aircraft are halted for such a time being. With continuous monitoring, as soon as the visibility improves the runways can be operated without any risks. Places like Delhi, Los Angeles, London which are prone to smog episodes can avoid major accidents by continuous air pollution monitoring.
Further by road surface condition monitoring integrated with airport air quality monitoring, the conditions of runways can be analyzed prior to take-off or landing of any flights to avoid major accidents. Indoor air purifiers and ventilation can be operated based on indoor air quality to conserve energy. (refer to environmental data-driven automation white paper to know more). Complain management systems can be integrated with the online monitoring systems to resolve the noise and poor air quality complaints, generating alerts for the civilians. Health alerts can be generated whenever a pollutant breaches the permissible limit issued by the authorities so that passengers suffering from respiratory diseases, senior citizens, small children can take precautionary measures. The recorded data serves as an important data sets for studies such as source apportionment studies or emission inventories of a city that helps in planning a pollution-free sustainable city.
As meteorological parameters such as temperature, humidity, wind speed, wind direction are also recorded, dispersion modeling can be carried out. Based on the dispersion study airports can issue real-time warnings to the residential areas or other sensitive receptors like parks or gardens through display screens or app alerts.
Oizom’s solution for airport air quality monitoring
Oizom has deployed a network of low-cost sensors, PolludroneTM at Riyadh King Khalid International Airport which is the second largest airport in Saudi Arabia. Due to frequent dust storms, the particulate matter concentration increased alarmingly which can cause acute asthma to the passengers. Polludrone monitored major pollutants like PM1, PM2.5, PM10, NO2, SO2, O3, H2S, CO, CO2, and other parameters like Noise, Temperature, Humidity and Wind speed, wind direction. Real-time data was provided to the authorities which were further analyzed to take corrective actions. It increased flight safety while taking off and landing. Air ventilation can be automated and optimized using Oizom’s devices to improve the indoor air quality of the airports.