Metro Manila smog not related to Taal Volcano: Phivolcs

MANILA (2nd UPDATE) — Smog blanketed parts of Metro Manila on Friday, prompting local governments to suspend classes.

The state weather bureau said the weather in Metro Manila, Calabarzon, and parts of Central Luzon is "conducive for haze or smog formation."

"This occurs when very small particles get trapped close to the surface due to the presence of a thermal inversion, high humidity, and calm wind conditions," PAGASA said.

The weather agency said "thermal inversion" happens when the atmosphere's layers "do not mix, causing aerosols to get trapped."

Phivolcs, meanwhile, said the volcanic smog or vog from Taal Volcano was drifting west-southwest and was "not going toward Metro Manila."

"The vog was over areas on the western side of Taal Volcano," Phivolcs told Palace reporters.

Science Secretary Renato Solidum said the vog from Taal and the smog caused by thermal inversion in Metro Manila were not related.

Solidum noted that thermal inversion happens when the cold air remains on top of the atmosphere, causing the fog, smoke, and vehicle emissions to be suspended.

"Yung temperatura, dapat yung hangin, habang tumaataas ang altitude doon sa kalawakan ay mas malamig, pero yung malamig na hangin ngayon ay nasa ibabaw lamang," he said in a public briefing.

"Imbes na umangat at ma-disburse, hindi umaangat dahil natutulak ng malamig na hangin pababa kaya mapapansin natin, buong Kamaynilaan at karatig na probinsya ay makulimlim, maliban sa cloud sa taas. Yun ay smog, smoke at fog," he added.

'HEAVY VEHICULAR EMISSIONS'

Solidum noted that the source of smoke in Metro Manila is the pollution from cars, while the smoke in Taal Volcano came from the volcanic gas.

The phenomenon experienced today can also be attributed from the lack of wind movement and the cold, moist air.

"‘Yan ay sanhi ng malamig na hangin, may moist, at mapapansin niyo, hindi mahangin. Wala masyadong hangin kaya hindi napapadpad o nadi-disburse ang ating mga smog o kaya ay vog," he said.

In a statement, the Department of Environment and Natural Resources' (DENR) Environmental Management Bureau (EMB) said their real-time quality monitoring tools "indicate heightened alert in some parts of Metro Manila, due primarily...to emissions from heavy vehicular traffic, especially during rush hour."

"Air quality varies in time and places and can change anytime depending on pollution sources and meteorological factors. DENR-EMB will continue to monitor air quality," the statement read.

VOLCANIC SMOG

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PAGASA weather forecaster Rhea Torres meanwhile said volcanic smog is hazardous, especially for those with lung ailments.

"Take note may sulfuric content ang hangin... Dapat magdala ng face mask," she said in a TeleRadyo Serbisyo interview.

She added that rainfall could help dissipate vog.

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In its latest bulletin, the Phivolcs said vog has been affecting the Taal Region since the first week of September. An average of 3,402 tons a day of volcanic sulfur dioxide or SO2 gas emission has been degassed from Taal Volcano for the month, it said.

Phivolcs said it monitored continuous upwelling at the Taal Main Crater Lake, from which steam plumes rose 2,400-meters high before drifting to the west-northwest.

The agency also detected 4,569 tons per day of volcanic sulfur dioxide or SO2 gas emission from the Taal Main Crater on Thursday.

"Satellite monitors have also detected a large cloud of SO2 over and stretching west of Taal Lake (Thursday)," it said.

PAGASA said the Intertropical Convergence Zone continues to affect Southern Luzon, Visayas, and Mindanao, bringing cloudy skies with scattered rainshowers and thunderstorms.