Taal Volcano emitted a record-high amount of sulfur dioxide (SO2), averaging at 14,326 tons per day, on June 28.
According to the Philippine Institute of Volcanology and Seismology (Phivolcs), the high levels of SO2, along with water vapor emitted in plumes, weak air movement, and solar radiation resulted in the volcanic smog or vog observed over the volcano.
Phivolcs has advised local government units in areas surrounding the volcano to conduct health checks on affected communities and to consider temporary evacuation of severely exposed residents, among other safety measures.
Here’s what you need to know about sulfur dioxide and how it can affect one’s health.
Sulfur dioxide or SO2 is a heavy, colorless, and poisonous gas. The Air Quality Management Section of the Department of Environment and Natural Resources says it is one of the major air pollutants monitored in the country. It is odorless at low concentrations, but it can have a “very strong smell” at high concentrations.
According to the World Health Organization (WHO), SO2 is produced from burning fossil fuel (coal and oil) and the smelting of mineral ores containing sulfur.
The 2005 air quality guidelines by the WHO say natural sources, including volcanoes, contribute to “environmental levels” of SO2.
Meanwhile, man-made contributions include the use of sulfur-containing fossil fuels, used in domestic heating, stationary power generation, and motor vehicles. High-sulfur coal is also used for power production.
As SO2 is highly soluble, it is readily absorbed in the upper respiratory tract, and its effects are enhanced if it penetrates lower regions through breathing through the mouth instead of the nose, and through exercise.
In terms of short-term exposures and their effects on pulmonary function, the WHO notes that there is a spectrum of sensitivity to SO2. Some people may be unaffected by a concentration that would cause severe bronchoconstriction in others.
The following are more sensitive to the effects of SO2 exposure:
Children, older adults, and people with asthma are at increased risk of hospital admissions or emergency room visits.
The WHO says the response to inhaled SO2 is “rapid,” with the maximum effect usually reached within a few minutes.
It adds that continued exposure does not generally increase the response, “and there is a tendency for it to decline gradually.”
In controlled studies with exercising asthmatics, it was indicated that some experienced changes in pulmonary function and respiratory symptoms within exposure periods as short as 10 minutes.
Depending on the individual and the severity, lung function may return to normal within minutes to hours.
Phivolcs advises people to avoid outdoor activities, stay indoors and close doors and windows, cover one’s nose, drink plenty of water to reduce throat irritation or constriction, and to seek medical help if needed. – Rappler.com
Loreben Tuquero is a researcher-writer for Rappler. Before transferring to Rappler's Research team, she covered transportation, Quezon City, and the Department of the Interior and Local Government as a reporter. She graduated with a communication degree from the Ateneo de Manila University.