EGU23-3834, updated on 10 Jan 2024
EGU General Assembly 2023
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Modeling outdoor dispersion of CO2 at Puerto Naos (La Palma, Canary Islands)

Luca D Auria1,2, Alba Santos1, Pedro A. Hernández1,2, Gladys V. Melián1,2, Antonio J. Álvarez Díaz3,4, María Asensio-Ramos1, Alexis M. González Pérez3,5, and Nemesio M. Pérez1,2
Luca D Auria et al.
  • 1Instituto Volcanológico de Canarias (INVOLCAN), 38320 San Cristóbal de La Laguna, Tenerife, Canary Islands (
  • 2Instituto Tecnológico y de Energías Renovables (ITER), 38600 Granadilla de Abona, Tenerife, Canary Islands
  • 3Instituto Volcanológico de Canarias (INVOLCAN), 38740 Fuencaliente, La Palma, Canary Islands
  • 4Agrolaguna, 38760 Los Llanos de Aridane, La Palma, Canary Islands
  • 5Hidrolap Medioambiental S.L., 38750 El Paso, La Palma, Canary Islands

The 2021 Tajogaite eruption in Cumbre Vieja volcano (La Palma, Canary Islands), which started on Sep. 19, 2021, and lasted 85 days, caused extensive damages because of the lava flows and ash fall. However, since the middle of Nov. 2021, some areas located about 5 km SW of the eruptive center started to be affected by intense diffuse CO2 emission. Among them are the urban centers of La Bombilla and Puerto Naos (Hernández et al., 2022). These emissions prevented the population of these two centers from returning to their houses because of high  concentrations of CO2 in indoor and outdoor environments.

In this work, we model the CO2 dispersion process in Puerto Naos to obtain hazard maps with the maximum CO2 concentrations which can be reached in the town in the outdoor environment. To achieve these results, we combined field observations with numerical modelling. Field surveys were realized in low wind conditions, measuring the CO2 concentration with portable sensors  at 15 and 150 cm from the ground at measurement points spaced approximately 10 m from each other along the streets of Puerto Naos.

We realized numerical modelling using the software TWODEE-2, a code for modeling the dispersion of heavy gases based on the solution of shallow water equations (Folch et al., 2009). For this purpose, we used a detailed digital topographic model, including the edifices of Puerto Naos. Using a trial-and-error approach, we determined the gas emission rates from a set of discrete source points in no-wind conditions. Subsequently, we repeated the numerical modelling, keeping the same sources and simulating all the realistic wind conditions in terms of direction and intensity. For each simulation, we determined the maximum CO2 concentration at different elevations from the ground. This allowed obtaining a hazard map with the maximum CO2 outdoor concentrations for each part of the town

The main results highlight that the outdoor environment is affected by a dense layer of CO2, whose flow is strongly conditioned by the urban infrastructures. Furthermore, we evidenced how even light winds can change the gas concentration pattern radically in a few minutes, evidencing the possibility of sudden changes in the CO2 concentration outdoors with no warning.

Folch A., Costa A., Hankin R.K.S., 2009. TWODEE-2: A shallow layer model for dense gas dispersion on complex topography, Comput. Geosci., doi:10.1016/j.cageo.2007.12.017

Hernández, P. A., Padrón, E., Melián, G. V., Pérez, N. M., Padilla, G., Asensio-Ramos, M., Di Nardo, D., Barrancos, J., Pacheco, J. M., and Smit, M.: Gas hazard assessment at Puerto Naos and La Bombilla inhabited areas, Cumbre Vieja volcano, La Palma, Canary Islands, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7705,, 2022.

How to cite: D Auria, L., Santos, A., Hernández, P. A., Melián, G. V., Álvarez Díaz, A. J., Asensio-Ramos, M., González Pérez, A. M., and Pérez, N. M.: Modeling outdoor dispersion of CO2 at Puerto Naos (La Palma, Canary Islands), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3834,, 2023.