Science and Technology Secretary Renato Solidum on Monday, Aug. 19 clarified that the haze observed over Metro Manila is not related to volcanic activity at Taal Volcano but is attributed to pollution.

Solidum told the Manila Bulletin that while volcanic smog or “vog” from Taal Volcano is present in some parts of Batangas province, it is not affecting Metro Manila.

“The smog in Metro Manila is due to pollution but the cause of both vog in Taal and smog in Metro Manila is the very slow wind speed in Luzon,” he added.

Solidum cited that Phivolcs' measurement of sulfur dioxide (SO2) emissions from Taal Volcano, recorded at 3,355 tons per day since Aug. 15, is considered “not highly significant.”

Phivolcs explained that the Taal Volcano area and Metro Manila have been experiencing unusually low wind speeds, averaging around 1 meter per second over the past three days.

It said the slow wind speed has contributed to the accumulation of pollutants and SO2 in the air.

“In Metro Manila, the haze we’re observing is most likely due to local pollutants rather than vog. The slow wind speed has also prevented these pollutants from dispersing vertically, causing them to remain at lower levels and create the haze we see,” Phivolcs said.

In a television interview on Monday, Phivolcs Director Teresito Bacolcol said the impact of the vog depends on wind direction.

Currently, he said the wind is blowing towards the west-northwest, which means the vog is not reaching Metro Manila.

The Phivolcs director said that as of now, the areas affected by vog are primarily around Taal Volcano, including parts of Batangas, such as Laurel, Tuy, Calaca, San Luis, Lemery, Balayan, Talisay, Agoncillo, San Nicolas, Balete, Sta. Teresita, Malvar, Alitagtag, and Batangas City.

However, he noted that if the wind were to shift towards the north, there is a possibility that the vog could extend to Metro Manila.