Haze over capital partly from Taal Volcano emission, but still mainly due to man-made smog — Phivolcs

THE HAZY sky over the capital region Metro Manila since Monday is partially due to plumes emitted by Taal Volcano but is largely on account of smog from human activities, the state volcanology agency said on Wednesday. In a statement, the Philippine Institute of Volcanology and Seismology (Phivolcs) said satellite data gathered in the past days show that the volcanic smog or vog from Taal has been dispersing over large parts of the northern mainland of Luzon. “The plumes extend from the planetary boundary layer or PBL, representing near-ground surface levels, to the upper troposphere at almost 20 kilometers above sea level and mostly spread over the Batangas, Laguna, Cavite, Rizal, Bulacan, Pampanga, Bataan and Zambales Provinces and the National Capital Region,” Phivolcs said. “Satellite detection on 29 June 2021 showed an even larger coverage of Luzon Island,” it added. On June 28, the agency released an alert on volcanic smog from Taal, but initially discounted public speculations “about the presence of sulfur dioxide (SO2) and vog in Metro Manila and the surrounding provinces based on their observations of haze.” “Our Institute had initially negated these observations due to the lack of substantiating evidence on our part and the general direction of wind and SO2 dispersal from Taal to the northeast and east since 28 June 2021,” it said. SO2 is a colorless toxic gas that can cause nose and throat irritation, and could be life-threatening when inhaled in large concentrations. But with the scientific data from various satellite platforms, Phivolcs said it “stands to acknowledge evidence of the wider extents that volcanic SO2 have actually spread” over the capital and surrounding provinces. “As a scientific institution, we have been reminded again of the value of uncertainty and the limitations of our data, the value of citizen observation and the need to constantly challenge our own perceptions… We would like to reassure the public that we are committed to provide the best and most current volcano monitoring data available, especially that these have important safety and health implications,” Phivolcs said. —