MANILA -- The haze over Metro Manila on Monday is likely caused by local pollutants and not by the Taal volcanic smog or vog, Philippine Institute of Volcanology and Seismology (Phivolcs )Director Dr. Teresito Bacolcol told ABS-CBN News.

Obscured skyline and poor air quality are being experienced in Metro Manila and nearby areas.

As of 10 a.m. Monday, the air quality monitoring of the Environmental Management Bureau of the Department of Environment and Natural Resources showed unhealthy air quality for sensitive groups in stations in Caloocan, Parañaque, and Pateros, while Makati logged very unhealthy air quality level.

Dozens of local government units surrounding Taal Volcano and even parts of Cavite, Laguna, and Metro Manila suspended face-to-face classes due to vog.

Over 40 LGUs suspend face-to-face classes due to Taal smog

In a bulletin on Monday, Phivolcs said Taal spewed 3,355 tons per day of sulfur dioxide on August 15. Bacolcol said this "isn't much."

However, due to the calm winds around the volcano, the gasses were not dispersed, leading to the formation of vog around the area.

Vog forms when sulfur dioxide interacts with moisture, surface oxygen, other volcanic gasses and particles, and sunlight.

In a health advisory issued on Monday, the Department of Health said vog could irritate the eyes, throat, and respiratory tract, which could lead to more serious conditions, depending on the amount or the duration of the exposure.

It also reminded the public to take the following precautions. 

1. Avoid going outdoors to limit exposure to vog.

2. Shut doors and windows to prevent the entry of vog at home. 

3. Cover nose and mouth and wear N95 mask, if available.

4. Drink lots of water.