Vulkanutbrott! Konsekvenser av svaveldioxidutsläpp
Transcription
Vulkanutbrott! Konsekvenser av svaveldioxidutsläpp
Vulkanutbrott! Konsekvenser av svaveldioxidutsläpp Hanne Krage Carlsen, MPH, PhD PostDoc fellow, Icelandic Directorate of Health & Centre of public health at University of Iceland September 2015 Iceland and volcanoes • Average one eruption every 5 years • Historically catastrophic events • Types: • Fissure => lava (tourist eruption) • Top crater => explosive with ash • No good studies of health effects 2 Barðarbunga/Holuhraun eruption • Seismic unrest August 2014 • Continued volcanic unrest near and under the main crater of Barðarbunga • Was there more to come? 3 Screenshot from vedur.is/en/earthquakes 16. August 2014 Barðarbunga/Holuhraun eruption • 31. august 2014-27.February 2015 • Eruption type: Basaltic lava flow • In the Barðabunga system • Largest since 1783-4 Laki eruption • but still only 10% of emissions of Laki • 12 million ton SO2 Reference http://www.geochemicalperspectivesletters.org/article1509 4 Image: University of Iceland Geoscience departmen Gas in volcanic eruptions • >95% • H2O, CO2 • SO2 • <5% • H2S, CO, HCl, HF Image:NASA/Landsat 5 SO2 gas properties • SO2 has no smell • Transient • Dose-dependent • Quite high dose needed before effects are seen • Susceptibility different in healthy individuals • Individuals with obstructive lung disease probably more susceptible 6 SO2 health effects • Irritation in eyes, nose, throat • Most gas is absorbed in nose and upper airways • SO2 in the lungs can provoke • Asthma attacks • Pulmonary oedema 7 Co-ordination! Frequent meetings arranged by the civil protection agency with representatives of • Police • Meteorological office • Earth scientists • Health authorities • Data-driven authoritative efforts based on newest data • • • • About eruption progress Closed areas SO2 levels Dispersion • Chief epidemiologists office 8 Informing the public - health behaviour The scientific advisory board bulletins were widely cited in the media. Official advice • SO2 transport to the lungs is minimized by breathing slowly and calm • Symptoms are immediate and resolve immediately after exposure stops 9 Gathering health information from professionals • Health directorate had frequent and persistent contact with MDs in the affected areas • Other: • Meteorological office collected reports online 10 Informing the public – health risks • Information relayed in media • Community meetings with directorate of health officials in the affected areas • Health effects table issued, update as new information was available and publicized widely • Increased monitoring www.landlaeknir.is/english/volcanic-eruption-in-holuhraun-human-health-effext/ 11 Pollution monitoring • 24-hour mean SO2 12 Pollution monitoring • 24-hour mean SO2 13 SO2 dispersion • Meteorological office made predictions • Warnings Published in the media • Accessible on the website vedur.is Meteorological office screenshot February 6 2015 14 Barðabunga/Holuhraun SO2 pollution • Eruption was very SO2 rich • First alarming message about SO2 levels from east Iceland • SO2 health limits (24 hour)* • 0-350 µg/m3 no risk • 350-600 µg/m3 probably effects in susceptible individuals • 600 *WHO air quality guidelines Unit: µg/m3 East Iceland Reyðarfjörður –Ljósá Vopnafjörður South Iceland Grindavik North Iceland Akureyri Capital Hafnarfjordur Nordlingaholt Maximum 24hour mean Days >24 hour limit** Days >1hour limit** 308 6 4 470 7 10 36 0 0 2025 4 6 323 479 8 9 6 15 9 The eruption in hindsight • No serious health events in the public attributed to SO2 • Several scientific studies ongoing: • Health of professionals who were highly exposed • Register-studies of the general public 16 Better prepared for next time? [email protected] 17