Urban Pollution Crisis in Metro Manila

More than two decades after leaded gasoline was phased out globally, toxic lead persists in Metro Manila’s air, and the sources have shifted from tailpipes to smokestacks. An international team of researchers analyzed aerosol data from 2018 and 2019 using lead isotope fingerprinting and found that lead pollution has taken on new forms and continues to circulate in the capital. This means the public health victory of removing leaded gasoline is not the end of the story — it is the beginning of a more complicated one.

Over 13 million residents are regularly exposed to pollution levels that exceed global safety standards, according to health experts who now describe the situation as a serious public health crisis. The invisible threats — fine particles carrying lead and other toxins — are contributing to respiratory, cardiovascular, and neurological diseases. For context, the State of Global Air 2024 report, cited by the Ateneo School of Medicine and Public Health, identifies poor air quality as the leading environmental threat to human health, accounting for 8.1 million deaths worldwide in 2021. That figure puts air pollution ahead of high blood pressure and smoking as a global killer. The challenge now is understanding what is still poisoning the air and what can be done about it. For a broader look at how the country is tackling environmental threats, see our overview of policy approaches to combat pollution in the Philippines.

What the latest research reveals about Metro Manila’s air

The core finding from the 2025 study published in Atmospheric Environment is that lead pollution in Metro Manila has not disappeared — it has changed form. The phaseout of leaded gasoline removed a primary pollutant, but the study points to industrial processes such as e-waste recycling and smelting as major contributors, accounting for up to 45 percent to 62 percent of atmospheric lead. Fossil fuel use, including diesel and trace elements in unleaded gasoline, contributes another 30 percent to 45 percent. As Dr. Maria Obiminda L. Cambaliza, an Ateneo de Manila University physics professor and study co-author, explained, there are now contemporary sources of lead mainly from industrial activities and fossil fuel combustion. Even unleaded gasoline still contains trace amounts of lead.

Contrary to patterns seen in other Philippine regions, Metro Manila’s pollution is largely from local emissions, persisting year-round regardless of seasonal shifts in wind patterns. As the metropolis expands, so do industries and energy systems reliant on fossil fuels, sustaining the cycle. The study’s authors note that geopolitical instability and surging global oil prices may delay the transition to clean energy, discourage proper vehicle maintenance, and heighten public exposure to toxic emissions. This traps communities in a cycle of economic pressure and environmental harm that intensifies each factor.

Why this matters for public health and who is most at risk

Lead is heavily concentrated in fine particulate matter that can be inhaled deeply into the lungs and absorbed into the bloodstream. This poses particular danger to children, who are vulnerable to lasting developmental and neurological harm. Globally, one in three children already has elevated blood lead levels, but the Philippines has not updated its national monitoring in nearly 20 years. That gap means policymakers and healthcare providers are operating with outdated information about how widespread the problem actually is.

Health experts warn that air pollution in Metro Manila has worsened from an environmental problem into a serious public health crisis. The Ateneo School of Medicine and Public Health has been vocal about the need for better data. Dr. Annelle Raphayette T. Chua, head of the Innovation Flagship Program at ASMPH Center for Research and Innovation, put it bluntly: air pollution is the leading cause of disease and early death worldwide, even more than high blood pressure or smoking, and yet there is not enough publicly available data to protect the populations most at risk. This is not just an academic concern — it affects real decisions about when children should be kept indoors, whether schools should suspend classes, and how hospitals prepare for pollution-related admissions. For more on how pollution specifically harms younger Filipinos, read our article on pollution’s toll on Filipino children’s future.

Without sustained intervention to address these emerging sources, the public health achievements of the past remain vulnerable to reversal amid increasing global uncertainty. 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 researchers said.

What gets overlooked in the air quality conversation

→ Scroll right to see all columns

Several nuances in the air quality conversation rarely get the attention they deserve. First, the assumption that banning leaded gasoline solved the lead problem is incorrect. The study shows that legacy pollution — lead deposited in soil and road dust over decades — gets resuspended into the air by traffic and wind. This means even if all industrial and fossil fuel sources were eliminated tomorrow, some lead would remain in the environment for years.

Second, the data gap is not just about lead. The Philippines lacks comprehensive, real-time monitoring for a range of pollutants. The Breathe Metro Manila coalition, which includes the Manila Observatory, Ateneo de Manila University, and environmental sensing company Clarity, is working to change this. Their goal is to expand real-time air quality monitoring and make pollution data accessible to decision-makers, healthcare providers, and the general public. As Dr. James Bernard Simpas, head of the Air Quality Dynamics Laboratory at the Manila Observatory, said: “You cannot manage what you cannot measure.” Long-term measurements illustrate the effectiveness of air quality policy decisions, and understanding the major sources helps direct mitigation strategies.

Third, the economic dimension is often framed as a trade-off between development and health, but the reality is more complex. Geopolitical instability and surging global oil prices may delay the transition to clean energy and discourage proper vehicle maintenance, heightening public exposure to toxic emissions. This creates a feedback loop where economic pressure and environmental harm reinforce each other. For a deeper look at how urban growth drives these problems, see our piece on urban expansion’s environmental toll in the Philippines.

What can be done: monitoring, policy, and individual action

Expanding real-time air quality monitoring

The Breathe Metro Manila coalition is advocating for stronger air quality monitoring and data-driven solutions. Their approach builds on decades of research from institutions like the Manila Observatory, which emphasizes the importance of continuous, localized measurement. Environmental sensing company Clarity is supporting the initiative through its Node-S Air Sensor, a self-powered monitor for particulate matter and nitrogen dioxide. Clarity’s platform promotes what it calls “Air Quality Monitoring 2.0,” which emphasizes smarter measurement systems, actionable data, and cross-sector collaboration. As Engr. Ethel Garcia, Regional Account Manager for SEA and Oceania at Clarity Movement, noted: “Air quality data is only powerful when it’s real-time, localized, and actionable.”

Using data to drive policy decisions

In Quezon City, Mayor Joy Belmonte recently updated the city’s class suspension protocols to consider real-time air quality as a factor. When levels reach “Very Unhealthy” or “Emergency,” classes are automatically canceled based on sensor data from 40 active monitoring sites. This is a concrete example of how localized data can translate into protective action. The Breathe Metro Manila coalition is calling on other local governments, private sector leaders, schools, and civic organizations to support similar efforts. The coalition’s operational hub, Ateneo BUILD (Business Insights Laboratory for Development), connects academic work with government, civic, and industry partners. As director Joseph Benjamin R. Ilagan put it: “Making air quality data public is a milestone. But more important is turning that visibility into shared decisions, and decisions into systems that improve how we protect our communities.”

Understanding the limits of individual action

While wearing masks, using air purifiers, and limiting outdoor activity during high-pollution days can reduce personal exposure, these measures do not address the root causes. The sources of lead and other pollutants are largely industrial and infrastructural — e-waste recycling, smelting, diesel combustion, and legacy soil contamination. Individual choices matter at the margins, but systemic change requires monitoring networks, emissions regulations, and enforcement. The Breathe Metro Manila coalition’s work aligns with the National Environmental Health Action Plan (NEHAP) 2030, which calls for strengthened systems that protect Filipinos’ health from environmental risks. For a related perspective on water pollution challenges, see our article on fighting water pollution from Manila to Boracay.

What to watch for next

The coalition’s goal is to expand real-time air quality monitoring across Metro Manila, making pollution data accessible to decision-makers, healthcare providers, and the general public. This is not a short-term project. It requires sustained investment in sensor networks, data infrastructure, and public education. The researchers behind the lead study emphasize that without continued vigilance, the gains from phasing out leaded gasoline could be undone. The next few years will determine whether Metro Manila builds the monitoring and regulatory systems needed to address its modern pollution sources or continues to rely on outdated assumptions about what is in the air.

Frequently asked questions about Metro Manila’s air pollution

Closing thoughts

The persistence of lead in Metro Manila’s air is not a sign that past efforts failed — it is a sign that the problem has evolved and requires a new response. The research is clear about where the pollution is coming from, and coalitions like Breathe Metro Manila are building the monitoring infrastructure needed to track it in real time. The next step is turning that data into decisions that protect the 13 million people breathing this air every day. If this was useful, you might also want to read how smog is choking other Filipino cities.

Sources

Manila’s air quality declared unhealthy on New Year’s Day — A look at how holiday celebrations spike pollution levels in the capital.

Coastal pollution’s impact on marine life — How pollution from urban centers reaches the ocean and affects ecosystems.

Toxic lead still persists in Metro Manila air amid fuel crisis despite interventions. BusinessMirror, 2026.

Air pollution in Metro Manila poses growing public health risk, experts warn. Manila Bulletin, 2025.

Breathe Metro Manila pushes for metro-wide air quality monitoring using real-time data. Clarity Movement, 2025.