AsianScientist (Jun. 16, 2026) – Since the 1920s, lead has been added to gasoline to enhance vehicle efficiency and engine performance. However, the use of leaded gasoline has exposed many people to lead poisoning, which is associated with elevated blood pressure, kidney damage, and impaired brain development and cognitive function in children.
In 2002, the United Nations Environment Programme (UNEP) launched a programme to eliminate leaded gasoline in road vehicles globally. In 2021, it marked the end of leaded petrol worldwide. According to UNEP, the official end of use of leaded petrol prevented more than 1.2 million premature deaths and saved USD 2.45 trillion a year.
However, the threat of lead remains significant, as global use of lead-acid batteries and other lead-containing products has driven lead consumption beyond levels seen during the leaded-gasoline era. Lead leakage into the environment now exceeds historical gasoline emissions, resulting in considerable environmental exposure.
The Philippines faces significant lead exposure issues, yet recent data is lacking. To fill this void, an international team, including researchers from the Ateneo de Manila University Department of Physics and the Manila Observatory, analysed aerosol data from 2018 and 2019 in Metro Manila using lead isotope fingerprinting.
They found that lead pollution has taken on new forms and quietly persists to this day, pointing to modern industrial activities, fossil fuel combustion, and legacy pollution as key sources of lead pollution in the nation’s capital. Their findings were published in the journal Atmospheric Environment.
To study this pollution, researchers collected aerosol samples over 16 months at the Manila Observatory as part of NASA’s CAMP2Ex project. The study focused on two particle sizes: 5.6–10 micrometres, similar to PM10 particles commonly used in air quality studies, and 0.56–1.0 micrometres, which contained the highest lead concentrations.
The collected particles were analysed to measure both water-soluble lead concentrations and lead isotopes. The coarse and fine particles were analysed separately to understand how pollution sources varied by particle size.
The scientists found that the chemical signatures of lead in Manila’s air did not change much across seasons, even though wind directions shifted during the monsoon periods, suggesting that most of the lead pollution comes from local sources rather than from long-distance transport from other countries.
The researchers also found that fine particles contained far more lead than coarse particles, especially particles smaller than 1 micrometre, which are usually linked to fossil fuel burning, industrial activities, and waste processing.
The lead signatures in Manila’s air matched sources such as diesel, unleaded gasoline, industrial emissions, and incineration ash more closely than natural rocks or older leaded gasoline sources.
The researchers also noted that some older lead from past gasoline use may still enter the air when contaminated soil is disturbed and resuspended as dust.
The study also found that industrial activities, including waste and e-waste processing, were the largest source of airborne lead, contributing around 45–62% of total lead pollution, whereas fossil fuel combustion from vehicles and fuel use contributed another 30–45%.
Comparison between Manila and other East and Southeast Asian cities, such as Bangkok and Singapore, showed similar lead signatures, possibly because they share similar urban pollution sources or because regional winds mix pollutants across cities.
In contrast, cities farther north, such as Beijing and Xiamen, showed different lead signatures likely linked to heavier coal use. Places like Taiwan and Haiphong showed greater seasonal changes in lead signatures because they are more affected by pollution transported across borders by monsoon winds.
“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 Maria Obiminda L. Cambaliza, the study co-author and Associate Professor, Department of Physics, Ateneo de Manila University.
“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,” added Cambaliza.
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Source: Ateneo De Manila University; Image: jcomp_Magnific
This article can be found at Lead sources detected in Manila’s air after the phase-out of leaded gasoline
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