The air we breathe may be causing more harm than we thought.
According to new research involving scientists from McGill University, tiny air pollutants known as PM2.5 could be responsible for far more deaths than previously estimated.
PM2.5 refers to fine particles in the air that are small enough to enter deep into our lungs and even get into our bloodstream. These particles come from car exhaust, factories, and even smoke from fires. They can cause heart disease, lung problems, and cancer.
The World Health Organization (WHO) has estimated that 4.2 million people die early each year because of long-term exposure to PM2.5 pollution.
But the new study shows that number could be even higher—possibly as many as 1.5 million additional deaths globally every year. That’s because the research found that even very low levels of PM2.5, levels once thought to be safe, can increase the risk of dying.
The research team, led by Professor Scott Weichenthal from McGill University, studied health and death records from seven million people in Canada over a 25-year period.
Canada has low levels of PM2.5 pollution, making it a good place to study the effects of these tiny particles at low concentrations. The researchers matched the health data with pollution data and found that even the lowest levels of pollution were linked to higher death rates.
By using this information, they created a new and improved model of how pollution affects health around the world. This updated model shows that lowering pollution levels—even those already thought to be low—could save many more lives.
In 2021, the WHO updated its air quality guidelines, cutting the safe limit for PM2.5 in half—from 10 micrograms per cubic meter to 5 micrograms. But the United States Environmental Protection Agency (EPA) still uses a standard of 12 micrograms, which is more than double the new WHO recommendation.
Professor Weichenthal says this study shows that following the new WHO guideline could have much bigger health benefits than anyone realized. He also suggests that future research should focus not just on how much PM2.5 is in the air, but what these particles are made of.
Some particles might be more harmful than others, and understanding their makeup could help us create smarter and more effective rules to protect public health.
This research highlights the urgent need for stronger environmental policies around the world. Reducing air pollution—even when levels seem low—can have a major impact on saving lives.
If you care about heart health, please read studies that Manganese can help clear arterial plaques and treat heart disease and Aspirin use linked to heart failure.
If you care about heart health, please read studies about the blood thinner drug that can prevent strokes in people with hidden heart issues and new guidelines on daily aspirin for heart attack and stroke prevention.
The study is published in Science Advances.
Copyright © 2025 Knowridge Science Report. All rights reserved.
