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| As many Idahoans remember, the May 18,
1980 eruption of Mt. St. Helens resulted in heavy ash fall and poor
air quality in many areas including Idaho. Renewed rumblings have
many wondering how a volcanic eruption 25 years later might impact
air quality and public health in our state and what can be done to
protect Idahoans from exposure to volcanic ash. |
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| What Is Volcanic Ash? |
| Volcanic
ash consists of small jagged pieces of rocks, minerals, and volcanic
glass the size of sand and silt (less than 2 millimeters [1/12 inch]
in diameter). Very small ash particles can be less than 0.001 millimeters
(1/25,000th of an inch) across. Unlike the soft fluffy material
created by burning wood, leaves, or paper, volcanic ash is hard,
does not dissolve in water, is extremely abrasive and mildly corrosive,
and conducts electricity when wet.
Ash falls vary widely in intensity, size of the ash particles, and
the degree to which light from the sun is obscured or blocked completely.
Ash falls may be accompanied by loud thunder and lightning and a
strong sulfur smell.
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| Potential Health Effects
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All residents of areas where
there is ash fall are at risk of breathing volcanic dust or getting
ash in their eyes. |
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Although volcanic ash is not poisonous,
it can cause short-term symptoms such as runny nose, sore throat,
chest tightness, dry cough, irritated or itchy eyes, and minor skin
irritations. |
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Short-term breathing of volcanic ash
is not known to pose a significant health hazard for healthy individuals. |
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Exposure to ash can make breathing difficult
for sensitive populations such as children, the elderly, and those
with respiratory conditions. People with chronic bronchitis, emphysema,
and asthma are most at risk. |
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Getting ash in the eyes can cause immediate
irritation. |
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Symptoms of breathing volcanic ash normally
disappear once the ash clears. |
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Studies of the effects of exposure to
volcanic ash in Oregon and Washington following the 1980 eruption
showed no severe or lasting health effects in people living in areas
of ash fall. |
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| Precautions - What
You Can Do |
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Minimize exposure to airborne ash. Stay
inside as much as possible. Keep children indoors when ash is visible
outdoors. Avoid strenuous activities. |
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If you have asthma or another respiratory
condition, make sure you have an adequate supply of medication, follow
your asthma or other breathing management plan, and contact your doctor
if you are having breathing or other health-related troubles. |
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Keep all doors and windows closed when
ash accumulation is heavy. |
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If you must go outside, wear a high-efficiency
face mask when outside to reduce inhalation of ash particles. Note:
Masks may make breathing more difficult for persons with existing
respiratory conditions. Remain inside until ash clears if you have
a respiratory ailment. |
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If no high-efficiency face mask is available,
improvise. Wear a fabric mask made from handkerchiefs, cloth, or clothing
to filter out larger ash particles. Dampen fabric with water to improve
effectiveness. |
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In fine-ash environments, wear goggles
or corrective eyeglasses instead of contact lens to protect eyes from
irritation. |
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Keep pets indoors. If pets go outside,
brush or vacuum them before letting them back indoors. If possible,
move livestock to a barn or other outbuilding and make sure they have
clean food and water. |
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When cleaning up ash outside, wear long
sleeves and pants, and a dust mask. To dispose of ash, bury, mulch,
or mix into soil. |
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Handle ash in open, well-ventilated
areas. Dampen ash in your yard to prevent billowing up into the air
and make cleanup less hazardous. When cleaning up ash, do not use
leaf blowers, reversed vacuum hoses, or other tools that stir up the
ash. |
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Protect your home from ash infiltration
by replacing disposable furnace filters or cleaning permanent filters
frequently. |
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Minimize risk of traffic accident by
avoiding driving in areas of heavy ash fall. |
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| Learn More
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| U.S.
Forest Service Mt. St. Helens VolcanoCam
View
image of Mount St. Helens, taken from the Johnston Ridge Observatory,
automatically updated approximately every five minutes. |
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Advisories
and Updates |
| U.S.
Geological Survey Current Update |
| National
Weather Service Ash Advisories |
| National
Weather Service Ash Trajectories |
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Health
Information |
Protecting
Yourself from Volcanic Ash
(Washington
State Department of Health Web site) |
Volcanic
Ash: Effects and Mitigation Strategies
(U.S. Geological
Survey Web site) |
Volcanic
Ashfall: How to Be Prepared for an Ashfall
(U.S. Geological
Survey Publication, November 1999: pdf 386 kb, 2 pages) |
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Other
Information |
| Mount
St. Helens, Washington
(U.S. Geological
Survey Mt. St. Helens home page) |
U.S.
Geological Survey Volcano Hazards Program
(U.S. Geological
Survey Volcanoes home page) |
Mount
St. Helens National Volcanic Monument
(U.S. Forest
Service Mt. St. Helens National Monument home page) |
Volcano:
Mt. St. Helens
(U.S. Environmental
Protection Agency Web site) |
