The study on the effects of chronic exposure to fine particulate air pollutants (PM2.5) reveals a concerning correlation with an increased risk of cardiovascular hospitalization among older adults, especially those living in socioeconomically deprived neighbourhoods. This research emphasizes the lack of a safe threshold for chronic exposure to PM2.5 concerning heart health. It critically evaluates the Environmental Protection Agency’s (EPA) recently updated standard for the U.S.’s annual average PM2.5 level, suggesting that it needs to effectively reduce the burden of cardiovascular disease and safeguard public health.
Originating from the Harvard T.H. Chan School of Public Health in Boston, MA, the study highlights the significant risk increase for cardiovascular hospitalization due to chronic exposure to PM2.5 among older adults. Yaguang Wei, the study’s lead author and a research associate in the Department of Environmental Health, underlines their findings’ crucial timing and significant implications. The study advocates for the necessity of air pollution control policies that are even more stringent than the current standards set by the Environmental Protection Agency, aligning more closely with the World Health Organization’s stricter guideline of 5 micrograms per cubic meter.
The EPA’s adjustment of the National Ambient Air Quality Standards announced on February 7, which reduced the permissible annual average PM2.5 level from 12 micrograms per cubic meter to 9 micrograms per cubic meter, remains above the recommended standard set by the World Health Organization. The study, slated for online publication in The BMJ on February 21, 2024, involved an extensive examination of hospital records and PM2.5 exposure levels for nearly 60 million Medicare beneficiaries aged 65 and over from 2000 to 2016. By integrating various air pollution data sources, the researchers were able to develop a predictive map of PM2.5 levels across the contiguous United States and link these levels to the residential ZIP codes of the beneficiaries.
This comprehensive analysis found that a three-year average exposure to PM2.5 significantly increases the risk of the first hospital admission for a range of cardiovascular conditions, notably ischemic heart disease, cerebrovascular disease, heart failure, and arrhythmia. At the current national average PM2.5 level of 7 to 8 μg/m3, the average annual risk of hospitalization for cardiovascular disease in seniors was 3.04%. In contrast, when chronic exposure to PM2.5 met the World Health Organization guideline of below 5 μg/m3, the average annual risk was reduced to 2.59%. It suggests that lowering average yearly PM2.5 levels to below 5 μg/m3 could decrease cardiovascular hospitalizations by 15%.
Despite these potential improvements, the study concludes that there is no safe level of chronic exposure to PM2.5 for cardiovascular health. It further notes that the health risks associated with chronic PM2.5 exposure remain substantial for at least three years and disproportionately affect individuals with lower educational achievements, limited access to healthcare, and those residing in socioeconomically disadvantaged neighbourhoods.
Joel Schwartz, the senior author and a professor of environmental epidemiology, emphasizes the urgent need for more vigorous efforts to improve air quality. That would help alleviate the burden of cardiovascular disease, which stands as a leading cause of death and a significant contributor to healthcare costs. The findings indicate that the EPA’s newly updated PM2.5 standard does not protect public health, highlighting the need for more stringent air quality standards to safeguard the population’s well-being, particularly the vulnerable older adult demographic.
More information: Yaguang Wei et al, Exposure-response associations between chronic exposure to fine particulate matter and risks of hospital admission for major cardiovascular diseases: population based cohort study, BMJ. DOI: 10.1136/bmj-2023-076939
Journal information: BMJ Provided by Harvard T.H. Chan School of Public Health
