The return of 800 more evacuated people to areas south of the lava flows took place as planned today. In the area Puerto Naos to the south coast of the lava flows, which remains evacuated due to the persistence of gases, new CO2 concentration data published by Involcan highlights this issue. Between the 9^th and 17^th of January, an optical CO2 sensor was installed in the ground floor of a building in Puerto Naos to measure the accumulation of gases. Throughout the week, concentrations ranged between 763 ppm and 44450 ppm, averaging 11921 ppm. The average value relates to a Yellow ‘Dangerous’ concentration of CO2, whilst the maximum value relates to a Red ‘Imminent danger’ concentration of CO2 as per the classification scheme used by Involcan. As warned previously by PEVOLCA, this represents the danger in these areas not just of high ambient CO2 concentrations, but also how CO2 concentrations can be especially elevated in enclosed, unventilated spaces, such as inside buildings.

Sources: Government of the Canary Islands, PEVOLCA, Involcan