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Mauna Loa

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Other Volcanoes

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About HVO

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Volcanic Hazards

Sulfur Dioxide, Vog, and Volcanic Ash
Frequently Asked Questions about Air Quality in Hawai`i


In response to public inquiries about air quality, HVO has compiled, with input from the Hawai`i State Department of Health, a list of Frequently Asked Questions about sulfur dioxide emissions, vog, volcanic ash, and air quality. Below each question, the symbol () indicates Web resources where you can find additional information.

1. What gases are emitted by Kīlauea and other active volcanoes?

2. Who monitors volcanic gases emitted by Kīlauea?

3. How do HVO scientists measure volcanic gas emissions?

4. How much sulfur dioxide (SO2) gas does Kīlauea emit?

5. How long will the Halema`uma`u vent emit high levels of SO2?

6. What is "vog"? How is it related to SO2 emissions?

7. Where and how do SO2 and vog affect air quality in Hawai`i?

8. What health hazards are posed by vog?

9. Where can I find results from scientific research or technical data about the effects of vog on human health?

10. Does vog impact plants and animals?

11. Where can I find results from scientific research or technical data about the effects of vog on Hawai'i plants?

12. Who monitors air quality—including vog—in Hawai`i?

13. Why are some roads and trails in Hawai`i Volcanoes National Park closed?

14. What can I do to minimize the risk of exposure to SO2 and vog?

15. Where can I find current information and data about air quality in Hawai`i?

16. Should I cancel my plans to visit to Hawai`i Island because of SO2 and vog?

17. How do other communities near active volcanoes deal with SO2 emissions?

18. What is volcanic ash?

19. Is this the first time Kīlauea has erupted volcanic ash?

20. Who monitors ashfall in Hawai`i?

21. How much ash is Kīlauea currently erupting?

22. Does volcanic ash pose hazards to human health?

23. What other hazards are associated with volcanic ash?

24. What can I do to minimize the impacts of volcanic ash?

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Updated: 19 June 2008 (pnf)