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Bali volcano ash cloud health impacts: Expert speaks

IF and when Mount Agung erupts on the holiday paradise of Bali, it won’t be the dramatic surge of lava or the pyroclastic flow Australian holiday-makers need to worry about.

Outside the evacuation zone, the real danger will be a volcanic ash cloud.

Experts can’t predict the nature of volcanic ash from Mount Agung any more than they can tell us when the simmering volcano will erupt, if at all.

But they do know volcanic ash is dangerous, and if Mount Agung blows, its ash cloud could wreck havoc on air travel, create health problems for locals and tourists, and could rain down like snow.

“Outside the evacuation area, you’d imagine the volcanic ash will be the main hazard if anything, so people should be prepared,” associate professor Heather Handley from Sydney’s Macquarie University told news.com.au.

She said volcanic ash was nothing like the kind of soft ash that remained after a fire.

“It’s volcanic material that’s less than two millimetres in size and it’s composed of little bits of jagged particles of volcanic glass,” Dr Handley explained.

“When you look at it under a microscope, [the glass particles] are really spiky most of the time.

“There’s also fragments of minerals in there, because you get minerals in the magma, and also little bits of rock too. That all form the ash when everything gets blown to smithereens.

“The hazard from the very fine volcanic ash is to aeroplanes, and obviously to people breathing it in.”


Volcanic ash can lead to respiratory problems, irritated eyes and, less commonly, skin irritation, according to the International Volcanic Health Hazard Network.

The network said ash particles could be so fine to be breathed deep into the lungs, which could lead to chest discomfort, coughing, a sore throat and wheezing.

People with existing respiratory issues, including those asthma, are considered most at risk of the respiratory effects of volcanic ash cloud.

Face masks are among the supplies being dispatched to evacuated communities by Indonesia’s national disaster agency as it prepares for the “imminent eruption” of Mount Agung.

Dr Jonathon Burdon, respiratory physician and chairman of the National Asthma Council, said the best advice to people with asthma in Bali was to stay inside if there was an ash cloud.

“If you are in Bali and you are exposed, you should stay indoors and keep out of it as much as possible,” he told news.com.au.

“Secondly, for all people with asthma, they should take their asthma medication readily as prescribed. We know about 40 per cent or so of people in Australia who are prescribed medication do not take it readily and then they wonder why they get into trouble.”

Dr Burdon said if a person’s asthma got worse with exposure to volcanic ash, they should use their crisis plan and if there was no relief, seek medical attention early.

He also said people should be careful with the face masks they used.

“We’d suggest you stay indoors but if you are outside, face masks will help, but you do need to have one that is tightly fitting around the nose and the mouth,” Dr Burdon said.

“A lot of those paper masks, like the ones we often see surgeons using, have leaks around the edges and they’re really not terribly effective.”


Macquarie University’s Dr Heather Handley said there was no way of knowing where an ash cloud would spread, if there even was one.

“It depends on the wind direction at the time of the eruption and how big the volcanic plume goes. It depends on what the eruption is, basically — it might be that only lava comes out for a while, or a big eruption with a big ash cloud that might go at least ten kilometres high,” she said.

“[The wind] could carry it to the northwest, like it did in 1963 [when Mount Agung last erupted], or it might carry it somewhere else.”

Emile Jansons, aviation services manager at the Volcanic Ash Advisory Centre — a section of the Australian Bureau of Meteorology — said in 1963, the volcanic ash that rained down in some parts of Bali was about 20 centimetres high — “which was enough to stop traffic”.

“The density is a lot more like snow,” Mr Jansons told news.com.au.

“It’s like pouring sand on top of buildings. If you have half a metre of ash, that’s the equivalent of a metre-and-a-half of snow.”

He said buildings and infrastructure could be crushed with the weight of the ash. The ash is also electrically conductive so the island’s electricity grid could also be cut.

Sulphur dioxide spewing out of the volcano could dissolve into water droplets and pour acid rain.

“It won’t melt your flesh, but it is irritating,” he said.

“If you’re in a position where you’re close enough and you’re having those sorts of effects there’s probably worse things you’re worried about like the ash and the dust that’s coming out, but these hazards, there’s nothing to say there’s going to be widespread ash fall.”


The fragments that make up volcanic can be catastrophic to aircraft.

“Because the glass fragments are quite jagged, and it is glass — it’s not like the ash that disintegrates in your fingers, it’s actually little fragments of rock — they can abrase the pilot windows and they can get into the engines,” Dr Handley said.

“And when it’s in the engines, because it is rock, it can start to melt as it gets hot. And then as it gets further into the engine it can start to fall and cause engine failure. So there is a risk.”

Mr Jansons from the Volcanic Ash Advisory said his team in Darwin was in constant contact with Indonesian authorities and the aviation industry as it watched for a possible eruption.

He said robust systems were in place to make sure planes weren’t flying into danger.

“There’s never been a volcanic ash incident which has caused a plane to crash,” he said.

“It has the potential to shut down jet engines if the plane is in the wrong place at the wrong time … and that’s why airlines are very responsible in their flight planning.

“They avoid flying over the tops of these volcanoes that might be about to erupt, and they also factor in how fast the ash is moving and where it will go.”

Still, travel expert Phil Sylvester from Travel Insurance Direct said Bali’s Denpasar airport was unlikely to take any chances.

“The prevailing winds in Bali at this time of year blow to the southeast — away from the airport, which is southwest of Agung,” he said.

“It’s likely flights will be grounded — at least initially — until meteorologists can assess the

danger to aircraft.”

— Additional reporting by Matt Young, youngma@news.com.au.

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