At first, I dismissed it as science fiction when a friend, who happens to be a scientist, told me that air pollution can affect food production. I thought he was joking, and that the idea came out of the blue. Air pollution harming crops? It sounded absurd.
But I was wrong; he was indeed right.
For generations, people have burned fossil fuels—coal, oil, and gas—to furnish heat for homes, energy for mobility, and power for the production of goods. Fossil fuels have become humanity’s tireless servants, and our mastery of their energy has transformed civilization. This command over energy has brought abundance, comfort, and convenience.
Yet too much of anything is dangerous. When energy is exploited to its maximum level, it becomes a dangerous servant. Our misuse of fossil fuels has resulted in air pollution episodes so severe that people have died.
The World Health Organization (WHO) reports that air pollution kills three times more people than vehicular accidents. In the Philippines, more than four percent of all deaths are attributed to air pollution, according to the World Bank. These numbers alone should alarm us—but they only tell part of the story.
Scientists classify air pollutants into two categories:
Primary pollutants—such as sulfur dioxide, nitrogen oxides, and particulates—are emitted directly into the atmosphere. They are generally present in high concentrations in urban areas or near large point sources like power plants.
Secondary pollutants, including ground‑level ozone, are formed through chemical reactions in the atmosphere. These pollutants can drift hundreds of kilometers away from their original sources, affecting regions that may not even appear industrialized.
Motor vehicles are major culprits. Studies show they account for about 30% of nitrogen oxide emissions, 50% of hydrocarbons, 60% of lead, and 60% of carbon monoxide in cities of developed countries. In dense city centers, the values rise dramatically—up to 95% for carbon monoxide and 70% for nitrogen oxides.
Until the mid‑20th century, air pollution was largely confined to industrial regions in developed countries. But in the last three decades, rising vehicle use and shifting emission patterns have pushed pollution far beyond city boundaries. Rural areas—once considered safe havens—are now increasingly exposed.
Unfortunately, in developing countries like the Philippines, public attention tends to focus on air pollution’s impact on human health in large cities such as Metro Manila. What most Filipinos don’t know is that polluted air in and around these cities, and even in surrounding rural areas, can also have significant impacts on agricultural production.
Even vegetables and crops grown organically are not spared.
“Air pollution’s damaging impact on human health is well established—but apart from its links to illnesses including heart disease and asthma, pollutants are also damaging the yield of food crops and other nutritional quality and safety, imposing a major risk to food security,” wrote Jessica Brown of the Sustainable Food Trust.
This claim is supported by a report titled A Hidden Threat to Food Production: Air Pollution and Agriculture in the Developing World, published by the London‑based International Institute for Environment and Development (IIED). The authors—Fiona Marshall, Mike Ashmore, and Fiona Hinchcliffe—warn that the agricultural impacts of air pollution are far more serious than previously understood.
Dr. Gerald Brust, an integrated pest management specialist at the University of Maryland, explains that burning fossil fuels releases sulfur oxides, nitrogen oxides (including nitrite and nitrate), ozone, and various hydrocarbons. These pollutants interact with crops in ways that are both visible and invisible.
The IIED report identifies three major pathways through which air pollutants damage agricultural production:
1. Direct Visible Injury. Pollutants can cause visible damage to leaf tissue—spots, bleaching, or necrosis. If the damage is extensive, crop yield suffers. Even superficial injury can make produce look less appealing, lowering its market value.
2. Direct Effects on Growth and Yield. Experiments show that crop yields generally decrease with increasing exposure to pollutants, even when no visible injury is present. Pollutants interfere with photosynthesis, respiration, and nutrient uptake.
3. Indirect Effects. Even at relatively low levels, pollutants may cause subtle physiological changes that do not immediately reduce yield. However, these changes can make crops more vulnerable to other stresses—heat, drought, pests, or diseases.
“For instance, exposure to sulfur dioxide consistently leads to increased growth rates of a range of aphid pests,” the authors noted. In other words, polluted air can make crops more attractive to insects.
The Philippines—along with Egypt, Malaysia, Bangladesh, and Indonesia—has been identified as having large areas of cultivated land in the “high risk category.”
Air pollution is no longer just an urban problem. It is an agricultural problem. It is a food security problem. And ultimately, it is a national problem.
The IIED authors emphasize that while changes in agricultural practices may help reduce impacts, the more urgent solution lies in reducing emissions of major pollutants and their precursors. They argue that environmental policy must evolve to reflect this reality.
Air pollution and agriculture should be integrated into: air quality standards, cost‑benefit analyses, urban planning, national land‑use planning and local environmental impact assessments. These are not merely technical concerns—they are matters of survival.
Cleaner air means healthier people, stronger crops, and more resilient food systems. The link between air quality and food production may seem invisible, but its consequences are not. The air we pollute today is the food we lose tomorrow.
And that is no longer science fiction. It is science fact.
