Mobile signals could help detect bushfire smoke levels

A new Dutch-Australian study shows that layers of smoke in the air affect the radio links between cell sites, providing a means to identify areas that are burning.

Glowing orange forest fire at night [destruction, bushfire]
byronsdad / Getty Images

A new study has seen potential for mobile phone signals and data to detect and measure bushfire smoke levels. The study was developed in collaboration with Delft University of Technology in the Netherlands, Wageningen University in the Netherlands, the Australian Bureau of Meteorology, and Monash University’s School of Earth, Atmosphere & Environment; it was published in the journal AGU Advancing Earth and Space Science.

Radio-link signal fluctuations were analysed during the 2019-2020 Australian bushfires, which resulted in 33 lives lost—including 9 firefighters—the loss of more than 3,000 homes, 17 million hectares burned, and the loss of a billion mammals, birds, and reptiles across the country.

The study noted that received signal levels from radio links have been used to accurately measure rainfall and humidity. The radio links—known as commercial microwave links—are the backbone of cellular communication networks and are made of a transmitting antenna and a receiving antenna at each cell site, operating in the microwave spectrum between 2GHz and 90GHz, spanning over hundreds of metres to tens of kilometres.

Radio links provide integrated measurements along their paths and are an untapped resource to complement air-quality monitoring stations in areas affected by smoke events and in developing countries without air-quality monitoring capability.

Observations showed that dry air containing large amounts of smoke in a surface layer above the ground acted as a lid, reducing dispersion, trapping and maintaining high ground-level concentrations of smoke. “These conditions also created anomalous propagation conditions for radio links from cellular communication networks. Unique signal patterns were identified and shown to be related to these specific atmospheric conditions and smoke concentrations by analysing the received signal levels of these links,” the study said.

That led to the researchers proposing “these routinely recorded data by telecommunication companies be used to predict smoke concentrations at ground level during haze events.”

Monitoring air quality is usually done by governmental agencies. Dedicated stations are expensive to maintain, so they are often located in densely populated areas to monitor particulate matter emissions related to road traffic.

The effect of smoke on new high-frequency links (71GHz to 76GHz and 81GHz to 86GHz) remains unknown, and future work should include data from the 5G infrastructure, the researchers wrote.

Ultimately, the study suggests there is great promise in complementing current initiatives, like satellite remote sensing, in sending early warnings to residents in affected areas and reducing the harmful impacts of smoke on people.

The study analysed data from more than 100 radio links operating in the larger Melbourne metropolitan area. The study suggested gathering larger amounts of data, such as those from the bushfires in Sydney and Canberra during the same period, for further analysis.

Copyright © 2021 IDG Communications, Inc.

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