Metro Manila’s air crisis runs deeper than the Navotas fire: lead, smoke, and an ocean at risk

By Francis Allan L. Angelo

The thick grey haze that choked the skies over the Philippine capital for nearly three weeks may be lifting, but scientists and conservationists warn that the Navotas landfill fire has exposed — and compounded — a far older and more stubborn crisis: Manila’s air has been quietly poisoned for years, and the damage may already be spreading to the sea.

Smoke recedes, but the reckoning remains

The Philippine Space Agency (PhilSA) confirmed on April 29 that nitrogen dioxide (NO2) concentrations over Metro Manila had fallen below pre-fire levels for two consecutive days — the first sign of meaningful air quality recovery since the Navotas landfill fire reportedly broke out on April 10.

Daily satellite monitoring using the Sentinel-2C satellite showed that by April 26, approximately 31.95 hectares — roughly 319,500 square meters — of the landfill had been reduced to charcoal, ash, and burned earth. At the height of the fire, smoke reached as far as Bataan province across Manila Bay, according to an earlier PhilSA bulletin released April 17.

“Coinciding with reports on Tuesday that significant progress has been made in suppressing the fire, satellite data shows that nitrogen dioxide concentration in Metro Manila has fallen below April 6 pre-fire levels for two consecutive days,” PhilSA said in its April 29 statement. The findings were corroborated by ground-level measurements from the Environment Management Bureau’s offices in NCR and Central Luzon, which recorded improvements in particulate matter (PM) on April 28 and 29.

NO2 is a pollutant produced by burning and a key component of smoke. PhilSA said it would continue monitoring to help quantify the impact of ground-level firefighting operations.

A bay at risk

As the fire smoldered, marine conservation group Oceana urged authorities not to focus on the air alone.

“Pollutants that are released and travel with smoke plumes will settle on land and water,” said Diuvs de Jesus, campaigns and science specialist at Oceana. Landfill leachate — the toxic liquid that drains from decomposing waste — combined with runoff from rain and firefighting water flowing over the site, could carry heavy metals and persistent organic pollutants into waterways that drain directly into Manila Bay.

Oceana called on the Navotas local government and the Department of Environment and Natural Resources (DENR) to strictly monitor water quality and sediment in affected areas. The group also urged the Bureau of Fisheries and Aquatic Resources (BFAR) to assess shellfish and crabs harvested near the site, which it said were at high risk of contamination.

“Precautionary measures should be done especially in the affected areas,” Oceana said, noting that communities dependent on Manila Bay’s fisheries could face an extended exposure risk even after the fire is fully extinguished.

Lead in the air, long after leaded fuel was banned

The Navotas fire arrived in the middle of a broader — and less visible — air pollution crisis that researchers have been documenting for years. A study published in February 2026 in the peer-reviewed journal Atmospheric Environment found that toxic lead persists in Metro Manila’s air more than two decades after the Philippines phased out leaded gasoline.

The research, led by an international team that included scientists from Ateneo de Manila University’s Department of Physics and the Manila Observatory, used lead isotope fingerprinting to trace the sources of lead-containing aerosols collected across Metro Manila in 2018 and 2019.

Their findings were striking: industrial processes — including e-waste recycling and metal smelting — account for 45 to 62 percent of atmospheric lead in the capital. Fossil fuel combustion, including diesel use and trace lead residues in unleaded gasoline, contributes another 30 to 45 percent.

“While the data was collected in 2018 and 2019, the conclusions remain relevant today,” said Dr. Maria Obiminda L. Cambaliza, a physics professor at Ateneo de Manila University and co-author of the study. “This research highlights the importance of monitoring atmospheric lead to ensure that we do not undo the gains from phasing out leaded gasoline.”

Unlike seasonal pollution patterns observed in other Philippine regions, Metro Manila’s lead contamination was found to be persistent year-round, driven by local emissions rather than shifting wind patterns. As the metropolis continues to expand — bringing with it more industrial activity and greater dependence on fossil fuels — the conditions that sustain lead pollution are deepening, not fading.

Children bear the greatest burden

The health stakes are severe. Lead accumulates in fine particulate matter small enough to be inhaled deep into the lungs and absorbed into the bloodstream. Children face the gravest risk: even low-level lead exposure is linked to irreversible developmental harm and neurological damage.

Globally, one in three children already has elevated blood lead levels. In the Philippines, the problem is compounded by a monitoring gap: the country has not updated its national atmospheric lead monitoring in nearly twenty years, leaving policymakers without current data to act on.

The ongoing global fuel crisis adds another layer of urgency. Rising oil prices may slow the Philippines’ already-delayed shift toward cleaner energy, discourage vehicle maintenance, and increase exposure to toxic combustion byproducts — locking communities into what researchers describe as a mutually reinforcing cycle of economic pressure and environmental harm.

A city watching the sky

For Metro Manila’s residents, the Navotas fire has made visceral what scientists have long documented in data: the air they breathe carries hidden hazards, from acute smoke to chronic industrial and vehicle pollution.

PhilSA has pledged to maintain its satellite-based monitoring of NO2 levels and to make space data accessible to disaster response agencies including the National Disaster Risk Reduction and Management Council (NDRRMC). But researchers and advocates say sustained, ground-level surveillance — of the air, the water, and the communities most exposed — is what will determine whether the gains of the last month hold.

“The persistence of lead in Metro Manila’s air serves as a reminder that environmental progress is not a finished chapter but a matter of continued vigilance,” the Ateneo researchers wrote.

The skies over Manila are clearing. The work is not done.

Sources: Philippine Space Agency (PhilSA), April 29, 2026; Oceana Philippines; Chen et al., “Lead sources detected in Manila’s air after the phase-out of leaded gasoline,” Atmospheric Environment, February 2026; Ateneo de Manila University Research Communications.