STO TOMAS City — A senior official from Phivolcs has advised the public to remain vigilant due to the possibility of volcanic smog, known as vog, making a return at any time.

This is as face-to-face classes at all levels have resumed in this city and surrounding local government units near Taal volcano, as it appears that the vog has subsided.

Nevertheless, Phivolcs Director Teresito Bacolcol emphasized the importance of staying alert for the potential reappearance of vog at Taal Volcano.

Even though the volcano had clear skies without vog since midday on Monday, he stressed the need for continued vigilance because vog could return.

He explained that the clear conditions were due to windy weather, which helped disperse the vog.

However, he cautioned that vog’s reappearance remains uncertain, influenced by factors such as wind speed, sulfur dioxide emissions, rainfall, and temperature.

Bacolcol also mentioned that vog would completely disappear when the surrounding area is free from haze and sulfuric odors.

Vog consists of fine droplets containing volcanic gases, particularly sulfur dioxide, and can linger when atmospheric layers prevent proper dispersion.

Exposure to vog can lead to irritation in the eyes, throat, and respiratory tract, with the severity depending on gas concentrations and the duration of exposure.

Taal Volcano is currently at Alert Level 1, indicating an abnormal condition with ongoing unrest and the potential for eruptive activity.

Access to Taal Volcano Island, especially the Main Crater and Daang Kastila fissures, remains restricted, and boating on Taal Lake is prohibited. (ai/mnm)

TAAL volcano is now clear of the smog caused by its emission of sulfur dioxide, which blanketed surrounding areas, forcing the suspension of work and classes on Friday, according to the Philippine Institute of Volcanology and Seismology (Phivolcs).

“In Taal, it’s clear now unlike the low visibility yesterday. So now, the Taal volcano is visible from Batangas, so basically, there is no vog already,” Phivolcs Director Teresito “Toto” Bacolcol said in an interview with The Manila Times on Saturday.

The Calabarzon Region (Cavite, Laguna, Batangas, Rizal, and Quezon), especially near the Taal Lake area, has been covered by thick vog caused by the continuous emission of sulfur dioxide by Taal since early September.

Phivolcs said it measured a total of 4, 569 tons of volcanic sulfur dioxide per day as of Thursday, September 21 As of 5:30 a.m. on Saturday, however, the agency reported that the gas emission from the volcano decreased to 2, 730 tons per day.

Meanwhile, the same Phivolcs official also declared that the haziness in the air being experienced by Metro Manila residents as that coming from smog and not vog. (Amado Inigo/MNM)