He Volcanological Institute of the Canary Islands (Involcan) There has been a significant decrease in the emission of sulfur dioxide (SO2) into the atmosphere by the La Palma volcano, during its post-eruptive phase, going from more than 100,000 tons per day to just three per day.
Involcan has continued to monitor the SO2 emission rates from the volcano that erupted in Cumbre Vieja in September 2021 and points out that they are “insignificant” when compared to those registered during the eruptive phase, when they reached values above 100,000 tons per day.
The records obtained during the post-eruptive phase reflect a significant decrease in SO2 emission levels that reach 2 orders of magnitude, from approximately 669 to 3 tons per day, the scientific institute has specified on its social networks.
During this post-eruptive phase and given the low SO2 emission rates from the La Palma volcano, the monitoring of this parameter has only been possible through observations made from the ground using miniDOAS-type remote optical sensors in position land mobile, and aerial with the instrumentation installed in an SUV and in an unmanned aerial vehicle, a drone, respectively.
The impact of the SO2 emission by the La Palma volcano during its post-eruptive phase on the SO2 immission levels in the Aridane Valley, that is, the concentration that this atmospheric pollutant emitted by the volcano reaches in the outdoor ambient air At ground level, “it has been and is relatively very small,” Involcan points out.
In this regard, he explains that the Air Quality Control and Surveillance Network of the Government of the Canary Islands has instrument stations in El Paso and Las Manchas that continuously record SO2 immission levels and the results obtained show that most of the records are less than 40 micrograms per cubic meter.
These immission levels are much lower than the SO2 hourly limit value (350 micrograms per cubic meter) for the protection of human health, according to the criteria established by current legislation on the Air Quality Index (ICA).
Within the framework of this legislation and the registration of these two monitoring and measurement points, it can be concluded that the air quality in the Aridane Valley, with regard to this atmospheric pollutant (SO2), is reasonably good (≤ 200 micrograms per cubic meter) and even good (≤ 100 micrograms per cubic meter)
Volcanic gas emissions are an integral part of volcano monitoring around the world and can be interpreted to understand the state of a volcano as well as the evolution of an eruptive process.
He adds that Involcan was the only Spanish scientific institution that monitored and measured the emission of sulfur dioxide (SO2) into the atmosphere during the eruption of the La Palma volcano.
This work was carried out in collaboration with the University of Manchester (United Kingdom) and during the eruptive process the monitoring of this parameter was carried out through observations made from the ground, by using remote optical sensors type miniDOAS on land in an SUV, for air with a helicopter and by sea with a patrol boat.
It was also carried out through satellite instruments (Sentinel-5P TROPOMI), whose data was combined with the PlumeTraj reverse trajectory analysis tools to generate subdaily SO2 emission data.
During the eruptive process and especially during its first 10 days, SO2 emission rates of more than 100,000 tons per day were recorded.
These high levels of SO2 emission and the enormous damage that the lava flows were already causing during those first 10 days led the Involcan to coin the Cumbre Vieja eruption of 2021 as the most important eruptive process in Europe in the last 75 years. observation that was transmitted to the Spanish and Canary Islands presidents, Pedro Sánchez and Ángel Víctor Torres, respectively, in the first half of October 2021.
The monitoring of this important parameter was essential to know the evolution of the eruptive process and even became a useful tool to predict the end of the eruption of the La Palma volcano with an “acceptable” certainty, continues the volcanological center.
The collaboration of the Civil Guard with its patrol boats and helicopters was very important so that Involcan could carry out this monitoring from the ground, adds the center, which also indicates that carrying out this scientific activity has been possible thanks to the VOLRISKMAC II (MAC2/3.5) project. b/328) co-financed by the European Commission through the INTERREG VA Spain-Portugal MAC 2014-2020 Cooperation Program.
