What Are the Effects of Gases From Volcanoes on Humans?

Volcanoes are an awesome and destructive force on the planet. They can blow debris and ash for miles, send flows of molten lava down their slopes, disintegrating everything in its path and can change the landscape of their surroundings permanently. Among the less obvious effects a volcano can have on the people nearby are the gases that are emitted during an eruption.

Carbon Dioxide

• Carbon dioxide contained in the magma inside the volcano is released into the atmosphere when the lava comes to the surface. Gas escapes into the air and can lead to deadly consequences. Most of the time the carbon dioxide is not concentrated enough in one area to cause death. However, on the Dieng Plateau in Java, Indonesia, carbon dioxide from an eruption in 1979 killed at least 149 people. Inhaling carbon dioxide suffocates the victim and can lead to death in a few minutes.

Sulfur Dioxide

• Sulfur dioxide is a common gas emission from a volcano. Unlike the colorless, odorless carbon dioxide, this gas causes a thick haze in the air and has a pungent smell often compared to rotten eggs. The gas can cause a burning sensation to the eyes, irritate mucous membranes and irritate the skin. Sulfur dioxide can cause upper respiratory and bronchial problems in those who inhale too much of it.

Volcanic Smog

• Volcanic smog, often referred to as "vog," is the result of high amounts of sulfur dioxide in the atmosphere from an eruption. The sulfur dioxide reacts chemically with sunlight, oxygen, dust and water to form the smog. This can cause poor air quality and hazy conditions but also makes for very attractive sunsets or sunrises, such as those normally seen off the coast of the Big Island of Hawaii when Kilauea is erupting.

Hydrogen Sulfide

• Hydrogen sulfide is a colorless, flammable gas present in volcanic eruptions. The strong-smelling gas is likened to sewer gas. It can cause upper respiratory irritation and may cause pulmonary edema with prolonged exposure. Symptoms of excessive inhalation of hydrogen sulfide include dizziness, excitement, staggering, headache, diarrhea and potentially bronchitis or pneumonia, according to the U.S. Geological Survey.