The Bali Volcano: What To Expect & How To Protect Yourself

As concern grows for both tourists and locals since the volcanic eruption of Mount Agung in Bali Indonesia I wanted to take a look at the risks to the health and wellbeing of those currently in Bali and what they can do to minimize exposure from the toxic ash spewing from the crater.

What Is Volcanic Ash?

Comprising fragmented rock particles no greater than 2 mm in diameter, volcanic ash is cool to the touch when it falls at a distance from the eruption and very hot at or near the source. Volcanic ash can differ in appearance from one volcano to another depending on the type of eruption and the volcano itself, influencing both the colour and size of the particles. During an eruption, airborne ash particles spewing from the volcano can severely reduce visibility and plunge a sunlit day into complete darkness. It’s not uncommon for thunder and lightning to occur, initiated by the friction of the particles as they collide with each other in the atmosphere.

Ash particles containing acid coatings fall from the sky during an eruption which may cause varying degrees of irritation to the lungs, eyes and skin. Once rain falls the acid is soon removed which can then go on to potentially pollute local water supplies and crops. Acidic ash is known to destroy vegetation and lead to crop failure. Oftentimes the travel plans of tourists and residents alike are severely impacted as airlines scramble to deal with a rush of frustrated and angry customers. Airport closures such as that currently experienced at Bali’s Ngurah Rai International Airport due to the eruption of Mount Agung, approximately two hours drive from Denpasar.

Volcanic eruptions pose relatively few health consequences for most people however due to the mental anguish caused to those situated nearby to the erupting volcano, many suffer from severe anxiety. Local hospitals and medical service providers can expect to see an uptake in admissions and patient visits during and after an ashfall event.


Respiratory Effects Of Volcanic Ash

A number of factors influence the degree in which people can be effected including;

  • The density and size of particles in the air;
  • The frequency and duration of exposure;
  • The concentrations or presence of aerosols; crystalline silica and volcanic ashes in the air together with the availability and access to respiratory equipment such as face masks, and the overall exposure period.

dust-mask-2 N95 Approved Mask

Effects Of Exposure To Volcanic Ash On Eyes

Eye exposure to volcanic ash can cause grit to accumulate in the eye causing painful scratches (corneal abrasions) and conjunctivitis. Those wearing contact lenses are more susceptible to the risk and should remove their contact lenses to prevent scratching of the eye. Symptoms include eyes becoming red, itchy or bloodshot, a sticky discharge or watering (tearing) of the eye and/or photosensitivity.

Volcanic Ash & Skin Irritation

Although relatively uncommon, volcanic ash can cause skin irritation for some especially if the ash cloud is acidic. Symptoms can include dryness followed by reddening or irritation of the skin, which when scratched can increase the risk of secondary infections.

Indirect Effects Of Ashfall

There are a number of localized impacts where large ashfalls have occurred including to the health and safety of the population in proximity to the volcanic event.


Bali is known for its constant interruptions to supply of electricity normally, and ashfalls can lead to issues with continuity of supply which may have implications on public health or other infrastructure in Bali. Wet ash is conductive posing a safety risk to workers working to clean power supply equipment.


Visibility when driving is significantly reduced from airborne ash clouds causing an increase in traffic accidents. Thin layers of dry and wet ash are extremely slippery making traction difficult. Additionally, road markings are often covered making it challenging to maintain identification of lanes and other road markings. Thick ash deposits may make some roads impassable, isolating communities.


Falling ash can clog and contaminate domestic water tank supplies and equipment effecting drainage and filtration systems impacting toxicity and potable water supplies . As a result of ashfalls, demand for water results in reduced supply and shortages impacting prices and availability. In Bali, tap water is not safe to drink. As a consequence the demand for bottled water will become a force multiplier.



Localized sanitation systems may be impacted by the fallout of ash into sanitation and municipal processing stations which can raise the risk of contamination and increasing disease in affected areas.


Due to the accumulation of ash on the roof of a home, collapse is likely to be common particularly in nearby villages where the structures are not built to an acceptable modern standard. Increased incidents of injury or death are often reported as a result of persons removing ash from the roof or from collapse when the structure gives way under the additional weight of the ash.

Animal Welfare

In the event toxic volcanic ash becomes coated with (hydrofluoric) acid, grazing animals ingesting the ash from grass and soil can become contaminated and die as a result. Family pets are not immune to contamination either. Should their feeding bowls be left exposed to ashfall pets may still consume the contaminated food and become ill or die as a result.

How To Prepare & Protect Yourself & Your Family

  1. Stock up on water as soon as possible. Store enough water for each family member for one week allowing for between 3-4 litres per person per day).

  2. Reduce the amount of ash inside your residence by keeping all doors and windows closed at all times.

  3. If possible wear eye goggles when outside and remove contact lenses to protect eyes from corneal abrasions. Even a pair of sunglasses is preferable to no eye protection at all.

  4. When venturing outdoors, wear an effective dust mask such as that recommended by The International Volcanic Health Hazard Network ( with an efficiency rating of N95. Alternatively a wet cloth can be placed over the nose and mouth to minimize exposure over a short term period.

  5. After an ashfall, driving conditions and visibility can pose significant risk to drivers and pedestrians alike. In the event that driving is a necessity, drive to conditions and ensure that you remain a large distance behind the vehicle in front.

  6. Ensure any locally grown fruit and vegetables are washed thoroughly in clean uncontaminated water before consuming.

  7. When cleaning ash from in and around the home, lightly water down ash deposits using a hose before shoveling. Sweeping dry ash can increase exposure and risk.

Sandra Hawkins

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