Environment
Fact-checked

At AllThingsNature, we're committed to delivering accurate, trustworthy information. Our expert-authored content is rigorously fact-checked and sourced from credible authorities. Discover how we uphold the highest standards in providing you with reliable knowledge.

Learn more...

What Is Vog?

Jessica Ellis
Jessica Ellis
Jessica Ellis
Jessica Ellis

Vog, or volcanic fog, is a combination of gases and particulate matter droplets known as aerosols which act as an air pollutant around active volcanoes. The existence of vog may present a danger to humans, and is connected to an increased risk of respiratory illnesses and the aggravation of existing respiratory problems. One of the best examples of volcanic fog is found on the Big Island of Hawaii, where the plumes spewing from the regularly active Kilauea volcano can affect air quality, visibility, and health risks throughout the southern islands of Hawaii.

Deep within an erupting volcano, magma is filled with dissolved substances that become gases when the molten rock rises toward the surface. These gases include several known pollutants, including sulfur dioxide, carbon dioxide, and carbon monoxide. As the gases bubble out from the volcano, they form large plumes that can then settle over the surrounding areas or be carried by winds to distant locales. Volcanoes also spew out substances known as aerosols, which are small clumps of particles or liquid drops suspended in gas that are believed to be responsible for some instances of climate change.

Vog around active volcanoes may affect air quality.
Vog around active volcanoes may affect air quality.

High in the atmosphere, the gases can increase ozone depletion, and may fall to earth as acid rain. Closer to the surface, a haze of vog can significantly reduce visibility and is linked to the aggravation of some respiratory illnesses. During a period of significant volcanic fog, cases of bronchitis, pneumonia, and asthma attacks may increase. Minor symptoms, such as allergies, headaches, and fatigue, may also be the result of heavy volcanic fog. Some studies suggest that children who are raised in an area regularly exposed to volcanic fog may suffer an increased risk for developing asthma and other chronic respiratory disorders.

Volcanic gases include sulfur dioxide, carbon dioxide, and carbon monoxide.
Volcanic gases include sulfur dioxide, carbon dioxide, and carbon monoxide.

While vog can occur following a large volcanic eruption, it may be a daily feature in any active volcanic area. On the Big Island of Hawaii, vog is a regular occurrence despite generally mild volcanic activity. Since the Big Island has such a high, persistent rate of volcanic fog, it is often the epicenter of studies to determine the movement and resultant pollution of the smog-like haze. The local government of the Island takes many precautionary measures, such as publishing a daily vog level index, to help citizens avoid the nasty side effects of vog.

Gasses from an erupting volcano can travel quite far away.
Gasses from an erupting volcano can travel quite far away.

In a volcanic area, people can often detect the pollutant fog simply by examining the air quality. Unlike smog, which is distinguished by a yellow tinge, volcanic fog is recognizable by blue-tinged air and significantly decreased visibility. Health experts suggest limiting outdoor exposure when vog levels are high, and installing air purifiers inside homes to reduce passive exposure. Those who experience side effects from heavy vog need to hydrate, drink warm liquids to loosen any mucus caused by the air pollution, and should not exercise outdoors.

Frequently Asked Questions

What exactly is vog?

Vog is a form of air pollution that results from volcanic emissions, which include gases like sulfur dioxide, carbon dioxide, and water vapor. When sulfur dioxide reacts with sunlight, oxygen, and atmospheric moisture, it forms a hazy mixture of sulfuric acid droplets and other fine particles, which can spread over large areas depending on wind conditions.

How does vog affect human health?

Exposure to vog can irritate the respiratory system, leading to health issues such as coughing, throat irritation, and breathing difficulties, especially in individuals with pre-existing conditions like asthma. According to the Hawaii State Department of Health, sensitive groups should limit outdoor activities and stay indoors with air purifiers during severe vog episodes.

Can vog have impacts on the environment?

Yes, vog can have detrimental effects on the environment. It can damage agricultural crops by inhibiting photosynthesis, as well as affect visibility and harm native ecosystems. The acidic nature of vog can also lead to the leaching of essential nutrients from the soil, impacting plant growth and soil health.

Is vog the same as smog?

No, vog and smog are different. Smog is air pollution primarily caused by vehicle emissions and industrial activities, which results in a mixture of smoke and fog, often containing ozone and particulate matter. Vog, on the other hand, originates from volcanic activity and is rich in volcanic gases and particles, including sulfur compounds.

Where is vog most commonly found?

Vog is most commonly found in areas with active volcanoes, such as Hawaii, where the Kīlauea Volcano is a significant source. The presence and concentration of vog in these areas depend on the volcano's activity level and prevailing wind patterns, which can carry vog to other regions, sometimes hundreds of miles away.

What measures can be taken to protect against vog?

To protect against vog, individuals should stay informed about air quality reports, especially in regions prone to volcanic activity. It's advisable to close windows, use air purifiers, and limit outdoor activities during high vog conditions. Wearing N95 masks can also help filter out fine particles for those who must be outdoors.

Jessica Ellis
Jessica Ellis

With a B.A. in theater from UCLA and a graduate degree in screenwriting from the American Film Institute, Jessica is passionate about drama and film. She has many other interests, and enjoys learning and writing about a wide range of topics in her role as a AllThingsNature writer.

Learn more...
Jessica Ellis
Jessica Ellis

With a B.A. in theater from UCLA and a graduate degree in screenwriting from the American Film Institute, Jessica is passionate about drama and film. She has many other interests, and enjoys learning and writing about a wide range of topics in her role as a AllThingsNature writer.

Learn more...

Discuss this Article

Post your comments
Login:
Forgot password?
Register:
    • Vog around active volcanoes may affect air quality.
      By: ID1974
      Vog around active volcanoes may affect air quality.
    • Volcanic gases include sulfur dioxide, carbon dioxide, and carbon monoxide.
      By: varts
      Volcanic gases include sulfur dioxide, carbon dioxide, and carbon monoxide.
    • Gasses from an erupting volcano can travel quite far away.
      By: Sunshine Pics
      Gasses from an erupting volcano can travel quite far away.