Air pollution is associated with significant health risks across all age groups. In a further concerning discovery, researchers have revealed that prolonged exposure to fine particulate air pollutants (PM2.5) could elevate the risk of hospitalizations due to cardiovascular diseases among older adults.

A U.S. study led by researchers from the Harvard T.H. Chan School of Public Health revealed that when the chronic exposure to PM2.5 was between 7 and 8 micrograms per cubic meter (μg/m3) -the current national average level - the average risk of hospitalization for cardiovascular disease in seniors was 3.04% each year. By lowering annual average PM2.5 levels from 7-8 μg/m3 to below 5 μg/, the overall cardiovascular hospitalizations could be reduced by 15%.

The release of these study findings coincides with the recent update by the Environmental Protection Agency (EPA) on the National Ambient Air Quality Standards. The revised standards aim to lower the permissible average annual PM2.5 level in the country from 12 μg/m3 to 9 μg/m3.

"The timing of our study couldn't be more critical, and its implications are profound. Our findings quantify the benefits of implementing stricter air pollution control policies—even stricter than the Environmental Protection Agency's new standards, which are considerably higher than the 5 micrograms per cubic meter standard set by the World Health Organization," said lead author Yaguang Wei, research associate in the Department of Environmental Health.

The findings were made after examining hospital records and PM2.5 exposure levels of nearly 60 million Medicare beneficiaries between 2000 and 2016. The participants were all above the age of 65.

The researchers developed a predictive map of PM2.5 levels across the country from a variety of air pollution data sources and linked it to the residential ZIP codes of beneficiaries.

The participants were followed up until their first hospitalization for any of seven major subtypes of cardiovascular disease (CVD): ischemic heart disease, cerebrovascular disease, heart failure, cardiomyopathy, arrhythmia, and thoracic and abdominal aortic aneurysms.

"The study found that three-year average exposure to PM2.5 was associated with increased risk of first hospital admission for all cardiovascular conditions, particularly ischemic heart disease, cerebrovascular disease, heart failure, and arrhythmia. For composite CVD, the study found that when chronic exposure to PM2.5 was between 7 and 8 μg/m3, representative of the current national average level, on average the risk of hospitalization for cardiovascular disease in seniors was 3.04% each year," the news release stated.

When chronic exposure to PM2.5 met the WHO guideline of below 5 μg/m3, the risk of hospitalization for CVD was found to be 2.59% each year.

Furthermore, the researchers noted that there is no established safe threshold for chronic exposure to PM2.5. The health risks persist significantly for a minimum of three years following chronic exposure, with a disproportionate impact on individuals with lower educational levels, restricted access to healthcare, and those residing in socioeconomically disadvantaged neighborhoods.

"Stronger efforts are urgently needed to improve air quality and thereby alleviate the burden of cardiovascular disease—a leading cause of death and a major contributor to health care costs. Our findings indicate that the EPA's newly updated PM2.5 standard is clearly insufficient for the protection of public health," said senior author Joel Schwartz.

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