The vog seen in Metro Manila and its neighboring provinces on Friday is not related to the Taal volcano, said Department of Science and Technology Secretary Renato Solidum on Friday.

In a press briefing, Solidum said the vog in the Metro is caused by thermal inversion wherein air temperature near the surface is colder than air above the surface.

"What is happening here in the Metro is different from the activities of the Taal Volcano," Solidum said in Filipino.

He explained that thermal inversion involves a change in the normal tendency of the air to cool down with altitude.

"But this cool air stays on the surface, that's why smog or vog remains instead of being dispersed, because of the pollution. As we notice the entire Metro Manila is shady and cloudy so that's smog, vog, or fog," he said.

While the origin of smogs in Metro Manila and Batangas are different, Solidum noted that these vogs can pose similar hazardous health impacts.

Solidum urged the public to stay indoors or wear N95 face masks when going outside their homes.

The thermal inversion contributes to cloud formation, fog, smog, lack of precipitation, and visibility disruption.

The thermal invasion is "prevalent" in the entire region, said Solidum.

It is a contributor to cloud formation, fog, smog, lack of precipitation, and visibility disruption.

"Here in Metro Manila, the source of smog comes from the car pollution while the smog in Taal Volcano is sourced from the volcanic gas," Solidum said.

Solidum said the pollutants causing smog in Metro Manila can be washed out once the heavy rains pour down.

However, he noted that a different scenario happens with the Taal's volcanic vog as acid rain can occur.

"But, of course, when it comes to the volcano, something different is happening there. It can still get washed down, but if the raindrops are tiny, the sulfur mixed with water results in acidic rain," said Solidum.

Acid rain can be easily detectable by the smell of sulfur as it would also cause harm to plants, he added.

The Philippine Institute of Volcanology and Seismology on Friday reported that Taal volcano has been releasing vog, which has coincided with the smog in Metro Manila.