Volcanoes release plumes of ash, dust, sulfur dioxide, carbon monoxide, and other harmful gases into the air. Sulfur dioxide is the most harmful of these gases. When the gases react with oxygen, moisture, and sunlight in the atmosphere, volcanic smog forms. This smog is a type of air pollution, which can be quite toxic.

Volcanic smog also contains highly acidic aerosols (tiny particles and droplets), mainly sulfuric acid and other sulfur-related compounds. These aerosols are small enough to be breathed deep into the lungs.

Breathing in volcanic smog irritates the lungs and mucous membranes. It can affect how well your lungs work. Volcanic smog may also affect your immune system.

The acidic particles in volcanic smog can worsen these lung conditions:

• Asthma
• Bronchitis
• Chronic obstructive pulmonary disease (COPD)
• Emphysema
• Any other long-term (chronic) lung condition

Symptoms of volcanic smog exposure include:

• Breathing problems, shortness of breath
• Coughing
• Flu-like symptoms
• Headaches
• Lack of energy
• More mucus production
• Sore throat
• Watery, irritated eyes

STEPS TO PROTECT AGAINST VOLCANIC SMOG

If you already have breathing problems, taking these steps can prevent your breathing from getting worse when you are exposed to volcanic smog:

• Stay indoors as much as possible. People who have lung conditions should limit physical activity outdoors. Keep windows and doors closed and the air conditioning on. Using an air cleaner/purifier can also help.
• When you do have to go outside, wear a paper or gauze surgical mask that covers your nose and mouth. Wet the mask with a solution of baking soda and water to further protect your lungs.
• Wear goggles to protect your eyes from ash.
• Take your COPD or asthma medicines as prescribed.
• Do not smoke. Smoking can irritate your lungs even more.
• Drink a lot of fluids, especially warm fluids (such as tea).
• Bend forward at the waist slightly to make it easier to breathe.
• Practice breathing exercises indoors to keep your lungs as healthy as possible. With your lips almost closed, breathe in through your nose and out through your mouth. This is called pursed-lip breathing. Or, breathe deeply through your nose into your belly without moving your chest. This is called diaphragmatic breathing.
• If possible, leave or do not travel to the area where the volcanic smog is.

EMERGENCY SYMPTOMS

If you have asthma or COPD and your symptoms suddenly get worse, try using your rescue inhaler. If your symptoms don't improve:

• Call 911 or the local emergency number right away.
• Have someone take you to the emergency room.

Contact your health care provider if you:

• Are coughing up more mucus than usual, or the mucus has changed color
• Are coughing up blood
• Have a high fever (over 100°F or 37.8°C)
• Have flu-like symptoms
• Have severe chest pain or tightness
• Have shortness of breath or wheezing that is getting worse
• Have swelling in your legs or abdomen

Vog

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Centers for Disease Control and Prevention website. Health effects of volcanic air pollution. www.cdc.gov/volcanoes/risk-factors/index.html. Updated April 22, 2024. Accessed May 24, 2024.

Feldman J, Tilling RI. Volcanic eruptions, hazards, and mitigations. In: Auerbach PS, Cushing TA, Harris NS, eds. Auerbach's Wilderness Medicine. 7th ed. Philadelphia, PA: Elsevier; 2017:chap 17.

Jay G. Volcanic eruption. In: Ciottone G, ed. Ciottone's Disaster Medicine. 3rd ed. Philadelphia, PA: Elsevier; 2024:chap 102.

Shiloh AL, Lewandowski DC. Mass critical care. In: Vincent J-L, Moore FA, Bellomo R, Marini JJ, eds. Textbook of Critical Care. 8th ed. Philadelphia, PA: Elsevier; 2024:chap 168.

United States Geological Survey website. Volcanic gases can be harmful to health, vegetation and infrastructure. www.usgs.gov/programs/VHP/volcanic-gases-can-be-harmful-health-vegetation-and-infrastructure. Accessed May 16, 2024.

Updated by: Allen J. Blaivas, DO, Division of Pulmonary, Critical Care, and Sleep Medicine, VA New Jersey Health Care System, Clinical Assistant Professor, Rutgers New Jersey Medical School, East Orange, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.