Chile’s Calbuco Volcano erupted third time on April 23, 2015. More than 4,400 people were evacuated by military and police force. A 20-kilometer (12-mile) exclusion zone has been established around the crater, and Chilean authorities have been keeping residents away from that zone. In Ensenada, houses, trees and even sheep were blanketed gray with ash. People were removing salmon — a staple of the local economy — because of fears of contamination from ash and lava. Trucks were used to evacuate farm animals and pets. Volcanic flows from Calbuco caused rising water levels in the Río Blanco.
Volcanic ash particles are pieces of pulverised rock like sand or rock dust made of silica with some amounts of potassium, aluminium and iron. Volcanic ash particles can affect the heart and lungs, especially in people who already have chronic heart or lung disease e.g. asthma, chronic obstructive pulmonary disease (COPD), or heart failure.
Precaution to be taken by elderly persons and pregnant women
The health impact of haze is dependent on one’s health status (e.g. whether one has pre-existing chronic heart or lung disease), the PSI level, and the duration and intensity of outdoor activity. Reducing outdoor activities and physical exertion can help limit the ill effects from haze exposure. Persons who are not feeling well, especially the elderly and children, and those with chronic heart or lung conditions, should seek medical attention.
Pregnant women and elderly persons should minimize and avoid outdoor activities.
Although the general advice to the public when the air quality is good or moderate (PSI≤100) is to maintain normal activities, vulnerable persons, especially those with chronic heart and lung conditions, who develop symptoms or feel unwell should seek medical attention promptly.
Impact of Volcano eruption on global climate
Volcanoes are the most dramatic and rapid agents of geologic change. An erupting volcano can eject vast amounts of ash and gases into the atmosphere, and cover the ground with tons of lava flows and ash. Eruptions create new mountains, and tear down old ones as we watch. Large eruptions are dangerous, sometimes killing tens of thousands of people at one time. But the most extreme impact of eruptions is their affect on Earth’s climate.
The most abundant gas typically erupted is water vapor, which has been measured to be as high as 97% of gases erupted from some volcanoes. The water has very little impact on climate because it usually rains out of the atmosphere fairly quickly. In fact, it is very common to find volcanic ash deposited that preserve rainfall splash marks.
The greenhouse gas carbon dioxide (CO2) is the second most common gas (varying from 1% to 50% in different types of eruptions). Carbon dioxide is heavier than air and commonly ponds in low-lying areas; it can poison and kill animals that breathe it. The CO2 does not significant influence climate because volcanic CO2 is only about 1% of what is released by burning of fossil fuels.
The gas that does have a noticeable climate impact is sulfur dioxide (SO2). Unlike greenhouse gases, SO2 cools the atmosphere. Magma contains a small amount of SO2, typically less than 10% by volume. Large eruptions thrust the SO2 into the upper atmosphere (the stratosphere) where it is transported around the planet. Contact with abundant water changes the SO2 gas into sulfuric acid (H2SO4) droplets called aerosols. Even though they are microscopic, there are billions of such aerosols following a big eruption, so that they actually affect the climate. Each aerosol absorbs some of the radiation from the Sun, and thus heats itself and the surrounding stratosphere. But each ray of Sunlight that hits an aerosol does not strike the Earth, robbing the surface of that small amount of heat. During the 1900s there were three large eruptions that caused the entire planet to cool down by as much as 1°C. Volcanic coolings persist for only 2 to 3 years because the aerosols ultimately fall out of the stratosphere and enter the lower atmosphere where rain and wind quickly disperse them.
We do not have control over geological changes happening in the crust of the earth. However, we can control the carbon and sulphur emission by reducing fossil fuel consumption.