Two recent large studies in the United States, shared by The BMJ, have unveiled a troubling link between air pollution, specifically fine particulate matter (PM2.5), and a heightened risk of hospital admissions for serious heart and lung conditions.
This discovery points to an unsettling reality: when it comes to heart and lung health, there might be no “safe” level of air pollution.
Fine particulate matter, or PM2.5, is a type of air pollution made up of tiny particles. These particles are so small that they can enter the lungs and even get into the bloodstream, causing a variety of health problems.
According to the Global Burden of Disease study, PM2.5 exposure is a significant global health risk, associated with 7.6% of total global deaths and 4.2% of disability-adjusted life years, which measure healthy years of life lost.
Recognizing the severe impact of PM2.5, the World Health Organization (WHO) updated its air quality guidelines in 2021.
These new guidelines are stricter, recommending that yearly average levels of PM2.5 should not go over 5 micrograms per cubic meter (μg/m3), and daily levels should not exceed 15 μg/m3 more than three to four times a year.
The first study focused on nearly 60 million U.S. adults over 65, tracking their health through Medicare data over eight years. Researchers connected the dots between PM2.5 levels in their residential areas and hospital admissions for several cardiovascular diseases.
They found that exposure to PM2.5 over three years significantly increased the risk of first hospital admissions for heart and vascular diseases.
Interestingly, areas with PM2.5 levels between 9 and 10 μg/m3, close to the U.S. average, saw a 29% rise in hospital admissions for these conditions.
This finding suggests that reducing PM2.5 levels to 5 μg/m3 or lower could prevent about 23% of these hospital admissions.
These effects of PM2.5 on cardiovascular health were noticeable for at least three years after exposure. The study highlighted that the risk varied based on factors like age, education, access to healthcare, and living in deprived areas.
Despite the U.S. Environmental Protection Agency (EPA) updating the national air quality standard for PM2.5 to a tighter limit of 9 μg/m3 in February 2024, researchers argue that this is still not strict enough to protect public health, especially when compared to WHO’s recommendation of 5 μg/m3.
The second study looked at hospital admissions and emergency department visits for over 50 million U.S. adults from 2010 to 2016.
It found that short-term exposure to PM2.5, even below WHO’s guideline limits, significantly increased hospital and emergency department visits for natural causes, cardiovascular, and respiratory diseases.
These findings challenge current air quality standards and suggest that stricter guidelines might be necessary to safeguard public health.
Both studies acknowledge limitations, such as potential misclassification of exposure and other unmeasured factors that might have influenced the results.
Also, these findings may not represent those without medical insurance, children, adolescents, and people living outside the U.S.
Nevertheless, these studies offer important insights into the impact of PM2.5 pollution on health and could inform future air quality standards, emphasizing the need for stricter regulations to protect against the hidden dangers of air pollution.
If you care about heart health, please read studies about the best time to take vitamins to prevent heart disease, and scientists find how COVID-19 damages the heart.
For more information about diabetes, please see recent studies that low calorie diets may help reverse diabetes, and 5 vitamins that may prevent complication in diabetes.
The research findings can be found in The BMJ.
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