Vog or volcanic smog from Taal Volcano has been observed in the past 24 hours, the Philippine Institute of Volcanology and Seismology (PHIVOLCS) said on Monday.

According to PHIVOLCS, vog is composed of sulfur dioxide (SO2) gas and other volcanic gases which mix with atmospheric oxygen, moisture, dust, and sunlight.

PHIVOLCS provided the following tips for protection from the effects of vog:

- Limit exposure or exposure:

• Stay away from sources of volcanic gas
• Stay indoors only and close windows and doors

- Protect yourself:

• Use an N95 face mask or gas mask
• Drink plenty of water to relieve irritation or constriction of the respiratory tract
• See a doctor or the barangay health unit immediately if necessary

Classes in some areas in Calabarzon were on Monday due to the vog.

In its latest , PHIVOLCS said that 3,355 tons of sulfur dioxide emission was also detected on August 15 and an upwelling of hot volcanic fluids in the Main Crater Lake was observed.

Voluminous emission of plumes of up to 2,400 meters tall were emitted from the volcano, drifting to the north-northwest direction.

The acidity was 0.20 and the temperature was 72.7 degrees Celsius in the Main Crater Lake on February 20, according to PHIVOLCS.

A long-term deflation of the Taal Caldera as well as a short-term inflation of the general northern and southeastern flanks of the Taal Volcano Island were also observed.

No volcanic earthquake was detected in the past 24 hours, PHIVOLCS said.

Alert Level 1 is maintained over Taal Volcano in Batangas, which means there is low-level unrest.

Under Level 1, the possible hazards are steam-driven or phreatic explosions, volcanic earthquakes, minor ashfall, and lethal accumulations or expulsions of volcanic gas.

The agency prohibited the entry into the Taal Volcano Island as it is a permanent danger zone or PDZ, especially the main crater and the Daang Kastila fissure.

Flying close to the volcano is also prohibited. —Joviland Rita/KG, GMA Integrated News