EGU23-6431, updated on 10 Jan 2024
EGU General Assembly 2023
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Chemical and isotopic composition of the indoor ambient air of Puerto Naos and La Bombilla, La Palma, Canary Islands

Fátima Rodríguez1, María Asensio-Ramos1, Gladys V. Melián1,2, Pedro A. Hernández1,2, Cecilia Amonte1,2, Antonio J. Álvarez Díaz3,4, Alexis M. González Pérez3,5, David Calvo1, Germán D. Padilla1,2, José Barrancos1,2, Víctor Ortega1, Iván Cabrera1, Eleazar Padrón1,2, Luca D'Auria1,2, and Nemesio M. Pérez1,2
Fátima Rodríguez 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

During and after the end of the 2021 Tajogaite eruption (La Palma, Canary Islands), anomalous CO2 degassing has been detected in the neighborhoods of La Bombilla and Puerto Naos, located around 5 km distance southwestern of the 2021 Tajogaite eruption vents. The aim of this study is to determine the indoor air quality of the houses of the aforementioned neighborhoods. For that purpose, from August 11 to October 24, 2022, air samples were taken, for further analysis, from indoors of 10 locations in Puerto Naos, on a weekly basis. In addition, on September 22, 2022, a discrete survey of the indoor ambient air was carried out in 10 houses of La Bombilla, consisting on in-situ measurements and gas sampling for further analysis.

Gas samples were taken for a complete geochemical characterization (i.e., He, Ar, Ne, H2, N2, O2, CH4, CO contents) by micro-gas chromatography (micro-GC) and quadrupole mass spectrometry (QMS) and, as well as for carbon isotopic analysis of the CO213C-CO2) by isotopic ratio mass spectrometry (IRMS). In-situ measurements of CO2, O2, 222Rn, 220Rn, H2S and Hg0 were conducted in La Bombilla with and without natural ventilation.

National Health Systems in the European Union reflect that the upper limit of the acceptable CO2 concentration range for long-term exposure in the indoor ambient air of buildings for residential use should be of the order of 1,000-1,200 ppm to guarantee people health. The concentrations of CO2 registered in the indoor ambient air of the 10 houses of La Bombilla determined by the in-situ measurements showed relatively high values -above 5,000 ppm- even reaching a maximum of 183,900 ppm in conditions without natural ventilation. In these conditions of absence of ventilation, a certain displacement of O2 was observed, which dropped to 18.7% in the worst case. Under conditions with natural ventilation for a period of 2 hours, the range of CO2 concentration fell to a range between 1,050 and 14,200 ppm and the O2 concentration registered was 20.9%. These results reflect that natural ventilation, and even more forced ventilation, would contribute to reduce CO2 concentration in the ambient air inside buildings. Regarding the results of the indoor gas samples analysis from Puerto Naos, the CO2 concentration and the δ13C-CO2 mean values ranged from 1,190 to 230,952 ppm and -7.9 to -4.8‰ vs. VPDB, respectively. These results of the chemical and isotopic composition of the indoor ambient air of Puerto Naos and La Bombilla demonstrate the importance of these studies to monitor and manage these silent hazards that pose a threat to the population and restrict access to their houses.

How to cite: Rodríguez, F., Asensio-Ramos, M., Melián, G. V., Hernández, P. A., Amonte, C., Álvarez Díaz, A. J., González Pérez, A. M., Calvo, D., Padilla, G. D., Barrancos, J., Ortega, V., Cabrera, I., Padrón, E., D'Auria, L., and Pérez, N. M.: Chemical and isotopic composition of the indoor ambient air of Puerto Naos and La Bombilla, La Palma, Canary Islands, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6431,, 2023.