Amid smog in capital region, gov't urged to improve 'outdated' air quality monitoring

Job Manahan, ABS-CBN News

Posted at Jun 30 2021 07:14 PM | Updated as of Jun 30 2021 10:25 PM

Amid smog in capital region, gov't urged to improve 'outdated' air quality monitoring 1
Smog continues to cover the Metro Manila skyline seen from Pasig City on June 29, 2021. Mark Demayo, ABS-CBN News

MANILA (UPDATED)— Environment group Greenpeace on Wednesday urged the Department of Environment and Natural Resources (DENR) to upgrade its “outdated” air quality monitoring system, as volcanic smog from Taal reached the Metro Manila and other provinces.

In a statement, the group said the volcanic smog, or vog, was compounded by human-made pollution in Metro Manila, as more vehicles hit the road due to looser lockdown levels in the middle of the pandemic. 

State seismologists earlier in the day said sulfur dioxide plumes emitted by the Taal Volcano earlier this week reached the planetary boundary layer or 20 kilometers above sea level, and has already “spread” throughout Batangas, Laguna, Cavite, Rizal, Bulacan, Pampanga, Bataan, Zambales, and Metro Manila.

The vog, or air pollution due to volcanic gas, was due to Taal's continued emission of high sulfur dioxide levels over the weekend, Phivolcs said. 

This is why Greenpeace said better air quality monitoring is important to gauge the toxic air pollutants present in such areas, which have health impacts. 

“While Phivolcs has clarified their earlier assessment of the air quality situation, without adequate and working air quality monitoring systems, the government will be stuck in an air pollution guessing game. Improved air quality monitoring, on the other hand, will yield valuable data that government agencies can act on,” Greenpeace campaigner Khevin Yu was quoted as saying.


A 1-kilometer warm layer of air is preventing cooler air near the ground to rise, trapping pollutants and driving the accumulation of sulfur dioxide plumes over the region, according to Phivolcs.

The temperature inversion might dissipate within 24 to 48 hours, Phivolcs officer-in-charge Renato Solidum added.

He advised affected residents to stay in their homes and wear N95 masks to block hazardous air particles. 

In a Twitter thread, Institute of Environmental Science and Meteorology (IESM) professor Dr. Gerry Bagtasa said the observed haze in various Metro Manila areas on Monday “was exacerbated by a strong inversion and weak winds.” 

Based on the model he showed, Bagtasa noted that Taal’s sulfur dioxide plumes were carried west, and moved northeast due to the monsoon, reaching the capital region. 

“Taal plume had northward movement traversing NCR, but with a more unstable atmosphere, it was not as bad as the [Monday] haze,” he wrote. 

Bagtasa said the sulfur dioxide (SO2) turned into sulfate aerosols in the air, thus making the haze whitish. 

“[These] are sulfate particulates already (not SO2) which differs from the typical dark skyline color due to soot. PM (particulate matter) is a health hazard,” he added. 

Amid smog in capital region, gov't urged to improve 'outdated' air quality monitoring 2
Dr. Bagtasa’s model showing the direction of Taal’s sulfur dioxide plumes, which already reached Metro Manila and other provinces north. 

Mariton Bornas, who heads Phivolcs’ Volcano Monitoring and Eruption Prediction Division, explained to ABS-CBN News that aside from the high sulfur dioxide levels, their satellite data also detected environmental pollution.

“Wala rin po kasing hangin so mabilis mag-accumulate ang pollutants then we also have the vog. ' Yung vog, hindi lang sulfur dioxide ang kailangan niyan. Kailangan po niyan ng moisture, may ibang kasamang aerosol or dust particles, and kailangan din po niyan ng solar radiation to form. Lahat ng ‘yan ay nasa bulkan,” Bornas told ABS-CBN News. 

(There is no air moving so the pollutants have accumulated, compounded with the vog. The vog does not only contain sulfur dioxide, it has moisture, aerosol or dust particles, it also needs solar radiation to form and they are all present at Taal)

The vog hovering around Taal’s nearby areas was also enhanced by these pollutants, as well as its position in the atmosphere, she noted. 

“Mas malayo po ang naaabot ng [smog sa] mataas (na part)” according to the official. 

(The smog could reach wider areas if it is higher.)


Greenpeace, on the other hand, said DENR’s PM2.5 air quality index sensors were “not working” as of Tuesday, despite detecting “hazardous PM2.5 levels” in the capital region since early Sunday. 

PM2.5 is a particulate matter that has a diameter of less than 2.5 micrometers. It is dangerous when inhaled because it could worsen health conditions such as asthma and cancer, Greenpeace’s Khevin Yu told ABS-CBN News. 

The pollutant is also usually emitted by cars and plantations. 

As of early Wednesday, the air stations of Metro Manila cities Parañaque, Taguig, and Las Piñas, which are nearest to Taal Volcano, posted a -9999.0 micrograms per normal cubic meter (ug/Ncm) of PM 2.5. 

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Muntinlupa’s air station, on the other hand, recorded 15.38 ug/Ncm of PM2.5.

Calabarzon’s air stations in Laguna were also offline as of this story’s posting, with the Environmental Management Bureau’s (EMB) dashboard indicating that there was “no air quality index data available at the moment.”

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The EMB dashboard said some of its air stations in Calabarzon were offline

As the presence of vog hounded various areas, Greenpeace reminded the public that the enhanced community quarantine (ECQ) last year “gave Filipinos a glimpse” of what Philippine cities could look like with improved air quality.

ABS-CBN News made a phone call to the office of engineer Jun Dy, the point person of EMB’s air quality division, but no one answered. 

The bureau has also yet to respond to queries on the matter sent via email. 


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