Volcanic Eruptions: Emitting Ash, Gas, And Air Pollution

Volcanic eruptions can cause air pollution in several ways. Firstly, they release toxic gases such as carbon dioxide, sulfur dioxide, and hydrogen sulfide into the atmosphere. These gases can travel far from the eruption site, reducing air quality and causing respiratory issues such as irritated eyes, skin, and lungs in people exposed to them. Additionally, when these gases combine with moisture in the atmosphere, they can fall as acid rain, damaging property and harming marine life and ecosystems. Volcanic eruptions also release fine particles of volcanic ash, which can travel long distances and contribute to air pollution, causing short-term irritation to the eyes, skin, nose, and throat. Furthermore, silica, a component of volcanic ash, has the potential to cause long-term health issues such as scarring in the lungs, known as silicosis.

Volcanic eruptions release sulphur gases, which combine with water vapour to form sulphuric acid

Volcanic eruptions are a significant source of air pollution. They emit toxic gases and fine particles that can cause harm to humans, animals, and the environment. One of the primary ways in which volcanic eruptions contribute to air pollution is by releasing sulphur gases, which combine with water vapour to form sulphuric acid.

Volcanoes emit a range of gases during an eruption, including water vapour, carbon dioxide, sulphur dioxide, hydrogen sulfide, and hydrogen halides. Water vapour accounts for about 70% to 95% of all eruption gases. The remaining gases, including sulphur dioxide, make up a small but significant portion. Sulphur dioxide is a colourless gas with a pungent odour. It is released from volcanoes and combines with water vapour in the atmosphere to form sulphuric acid. This process is accelerated by the presence of sunlight.

The formation of sulphuric acid from the combination of volcanic sulphur dioxide and water vapour has significant impacts on the environment. Sulphuric acid in the atmosphere can lead to acid rain, which is harmful to vegetation, aquatic ecosystems, and infrastructure. Additionally, sulphuric acid aerosols in the atmosphere can reflect sunlight, causing a cooling effect on the Earth's climate. This phenomenon was observed after the eruption of Mount Pinatubo in 1991, where the injection of sulphur dioxide into the stratosphere resulted in a decrease in average temperatures in subsequent years.

The health hazards of sulphuric acid are also a significant concern. Volcanic smog, or "vog", is formed when sulphur dioxide emissions react with sunlight, atmospheric gases, and aerosols to create fine particles of sulphuric acid. This toxic mixture can cause serious respiratory issues and other health problems for people living downwind of a volcano, as seen in Hawaii, where the Kilauea volcano has been continuously erupting since 1983. The fine particles in vog can be inhaled, leading to irritation of the eyes, skin, nose, throat, and respiratory system.

Furthermore, the release of sulphur dioxide and its subsequent transformation into sulphuric acid can contribute to ozone depletion. Sulphuric acid aerosols provide sites for chemical reactions that release chlorine atoms, which then destroy ozone molecules. This effect, combined with the use of CFCs by humans, poses a significant threat to the ozone layer, which protects all life on Earth from harmful UV-B radiation.

Volcanic ash can travel thousands of miles, causing eye and throat irritation and affecting those with respiratory issues

Volcanic ash can travel hundreds to thousands of miles, causing eye and throat irritation and affecting those with respiratory issues.

Volcanic ash is composed of fine particles of fragmented volcanic rock, often hot very close to the volcano but cools as it travels further distances. These fine particles can be breathed in and lodge in the upper airways, causing throat irritation and a sore throat. In high exposure, even healthy individuals will experience chest discomfort with increased coughing and irritation. The irritation can be so severe that it causes painful scratches to the cornea and conjunctivitis.

The effects of volcanic ash on the eyes can include:

• Foreign body sensation
• Itchiness
• Bloodshot eyes
• Sticky discharge or tearing
• Corneal abrasions or scratches
• Acute conjunctivitis, leading to redness, burning, and photosensitivity

Volcanic ash can also affect the skin, especially if the ash is acidic. Symptoms of skin irritation include:

• Irritation and reddening of the skin
• Secondary infections due to scratching

The effects of volcanic ash are not usually considered harmful to those without pre-existing respiratory conditions. However, it is recommended that people take steps to minimise their exposure to breathing in airborne ash. Volcanic ash can be carried by the wind and travel thousands of miles, causing eye and throat irritation and affecting those with respiratory issues such as asthma or bronchitis. Those with pre-existing respiratory conditions may experience severe bronchitic symptoms that last several days beyond exposure to the ash, including a hacking cough, production of sputum, wheezing, and shortness of breath.

Volcanic gases can cause acid rain, which damages property and ecosystems

Volcanic eruptions release large quantities of greenhouse gases and other aerosols into the atmosphere. These gases form massive clouds that accumulate in the atmosphere, a process known as outgassing or off-gassing. While water vapour is the most abundant volcanic gas and is harmless, significant amounts of carbon dioxide, sulfur dioxide, hydrogen sulfide, and hydrogen halides can also be emitted, posing potential hazards to people, animals, agriculture, and property.

Sulfur dioxide (SO2) emissions can cause acid rain and air pollution downwind of a volcano. When SO2 is introduced into the atmosphere, it undergoes a chemical reaction with other atmospheric aerosols and water vapour, producing sulfuric acid (H2SO4). This sulphuric acid takes on a hygroscopic characteristic, giving the sulphuric aerosols a residence time of months to even years. This extended presence in the atmosphere allows sulphuric acid to be carried long distances according to wind direction and meteorological conditions.

Acid rain with a pH of 2.5-5.0, dominated by hydrochloric acid (HCl) and sulfuric acid (H2SO4), can have detrimental effects on the environment. It can poison drinking water supplies, damage agricultural crops, and harm grazing land. In 2008, the eruption of Rebel Dragon in Arakan destroyed 100 acres of cropland due to the combination of pyroclastic flow and acidic rain. Acid rain can also corrode buildings, dissolving lead and other materials into water supplies.

In addition to the environmental and ecological damage, acid rain can also impact human health. The World Health Organization recommends a concentration of no greater than 0.5 ppm of sulphuric acid over 24 hours for maximum exposure. Concentrations of 6-12 ppm can cause immediate irritation of the nose and throat, while 20 ppm can lead to eye irritation, and 10,000 ppm will irritate moist skin within minutes. Exposure to high concentrations of sulphuric acid can result in respiratory issues, headaches, dizziness, increased heart rate, and difficulty breathing.

Volcanic smog, or 'vog', is a type of air pollution that can irritate the lungs and mucous membranes

Volcanic smog, or vog, is a type of air pollution that is primarily associated with the Hawaiian Islands. It is caused by the Kīlauea volcano, which erupted continuously between 1983 and 2018. Vog is a portmanteau of the words "volcanic" and "smog". It is formed when volcanic gases, primarily sulfur dioxide, react with sunlight, oxygen, and moisture in the atmosphere. This reaction produces sulfuric acid and other sulfates, which combine with the volcanic gases to create a mixture of gases and aerosols.

Vog poses a significant hazard to human health, particularly for those with pre-existing respiratory conditions. Sulfur dioxide irritates the skin, eyes, nose, throat, and mucous membranes, and can cause respiratory distress. It can also induce symptoms of asthma and lead to headaches, watery eyes, sore throat, flu-like symptoms, and fatigue. The aerosol particles in vog can penetrate deep into the lungs and remain there, potentially impairing lung function. The long-term health effects of vog exposure are currently unknown.

In addition to its impact on human health, vog can also damage or kill plants. The sulfuric acid droplets in vog have corrosive properties similar to battery acid. When vog comes into direct contact with moisture on plant leaves, it can cause severe chemical burns, damaging or killing the plants. Vog can also negatively impact agriculture, contaminating water supplies, and reducing visibility for drivers, air traffic, and ocean traffic.

Volcanic eruptions release carbon dioxide, which can collect in low-lying areas and pose a lethal risk to humans and animals

Volcanic eruptions are a source of air pollution, releasing large quantities of greenhouse gases and other aerosols into the atmosphere. These gases form massive clouds that can accumulate and inflict detrimental impacts on the rest of the globe.

Volcanic eruptions release carbon dioxide, which is the second most prevalent contributor to atmospheric greenhouse gases. Carbon dioxide is heavier than air, so it collects in low-lying areas, posing a lethal risk to humans and animals. Breathing air with more than 3% carbon dioxide can quickly lead to headaches, dizziness, increased heart rate, and difficulty breathing. At mixing ratios exceeding about 15%, carbon dioxide causes unconsciousness and death. The boundary between healthy air and lethal gas can be extremely sharp; even a single step upslope may be enough to escape death.

Volcanoes release up to 130 million tons of carbon dioxide into the atmosphere each year. In comparison, human activities emit 60 or more times the amount of carbon dioxide released by volcanoes annually. While large, violent eruptions may match the rate of human emissions for the few hours that they last, they are too rare and fleeting to rival humanity's annual emissions.

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