Toxic lead lingers in Metro Manila air

More than two decades after the phaseout of leaded gasoline, hazardous lead particles continue to circulate in Metro Manila’s air—now driven by newer, less visible sources.

A research team, including scientists from the Ateneo de Manila University Department of Physics and the Manila Observatory, analyzed aerosol samples from 2018 and 2019 using lead isotope fingerprinting. 

Their findings reveal that while leaded fuel is no longer the primary culprit, pollution persists through modern industrial activity, fossil fuel combustion, and residual contamination.

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

The study found that industrial processes—particularly e-waste recycling and smelting—now account for as much as 45 to 62 percent of airborne lead in Metro Manila. Fossil fuel use, including diesel emissions and trace elements in unleaded gasoline, contributes another 30 to 45 percent.

“There are now contemporary sources of lead, mainly from industrial activities such as e-waste processing, and fossil fuel combustion such as from diesel use and unleaded gasoline combustion. Indeed, trace amounts of lead may still come from unleaded gasoline,” Cambaliza underscored.

Unlike other parts of the Philippines where pollution levels fluctuate with seasonal winds, Metro Manila’s lead contamination is largely homegrown—emanating from local, year-round emissions tied to urban expansion and energy use.

Experts warn that global instability and rising oil prices could further complicate efforts to reduce pollution, potentially slowing the transition to cleaner energy while increasing reliance on older, more polluting systems.

The health risks remain severe. Lead particles, often embedded in fine particulate matter, can be inhaled deep into the lungs and absorbed into the bloodstream. 

Children are especially vulnerable, facing long-term developmental and neurological damage. Globally, one in three children already has elevated blood lead levels, yet the Philippines has not updated its national monitoring data in nearly two decades.

“The conclusions in the paper remain relevant today, even though the data were collected in 2018 and 2019. This research highlights the importance of monitoring atmospheric lead to ensure that we do not undo the gains from phasing out leaded gasoline,” Cambaliza stressed.

The findings underscore a sobering reality: while past policies curbed one major source of pollution, new threats have emerged. 

Without sustained monitoring and intervention, earlier environmental gains risk being undone—leaving Metro Manila’s residents exposed to a silent but persistent danger.