Bottom Line: Short-term exposure to air pollution at levels below current air quality standards were associated with a higher risk of death in older adults.
Why The Research Is Interesting: The Clean Air Act requires that National Ambient Air Quality Standards for fine particulate matter and ozone be reviewed every five years. Estimates of the risk of death at air pollution levels below the current standards are needed and a large study population is necessary to calculate those.
Who and When: Medicare patients throughout the United States from 2000-2012 living in more than 39,000 zip codes.
What (Study Measures): Estimated daily ambient fine particulate matter and ozone levels (exposures); death (outcome)
How (Study Design): This is a case-crossover study, a kind of study design used in epidemiology to study outcomes from a suspected transient exposure like air pollution in a large population over time.
Authors: Joel D. Schwartz, Ph.D., of the Harvard T.H. Chan School of Public Health, Boston, and coauthors
Results: Daily increases in fine particulate matter and ozone were associated with increased risk of death among more than 22 million Medicare beneficiaries, even when fine particulate matter and ozone levels were below current air quality standards.
Study Limitations: The findings are unlikely to be generalizable to adults younger than those enrolled in Medicare.
Study Conclusions: Current national air quality standards may need to be reevaluated because exposure to fine particulate matter and ozone at levels below those standards were associated with increased risk of death in a study of the Medicare population.
Related material: The following related material is available on the For The Media website:
The editorial, "Low-Level Air Pollution Associated With Death," by Junfeng Zhang, Ph.D., of Duke University, Durham, North Carolina.
For more details and to read the full study, please visit the For The Media website.
Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.
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