A number of studies have documented a strong correlation between long-term exposure to fine particulate and greater human mortality, but some concern has remained about the causal nature of the evidence, and whether it is sufficient to inform revisions to air quality standards. Scientists recognize that particulate and non-particulate air pollutants are a spring of potential damage to human health. Some scientists argue, anyway, that modern causal inference methods can provide such evidence, using the right data. Causal inference can quantify and visualize how close our data are to approximating a randomized controlled study, the gold standard for assessing causation. According to a new study from Harvard T.H. Chan School of Public Health, strengthening U.S. air quality standards for fine particulate pollution to be in compliance with current WHO guidelines could save more than 140,000 lives over the course of a decade. A new analysis of 16 years of publicly accessible health data on 68.5 million Medicare enrollees provides broad evidence that long-term exposure to fine particles in the air – even at levels below current EPA standards – leads to increased mortality rates among the elderly.
Based on the results of five complementary statistical models, including three causal inference methods, the researchers estimate that if the EPA had lowered the air quality standard for fine particle concentration from 12 μg/m3 down to the WHO guideline of 10 μg/m3, more than 140,000 lives might have been saved within one decade. The new study is likely to inform national discussions around updating air quality standards, for example, the National Ambient Air Quality Standards by the EPA. Analyzing a massive dataset through five distinct approaches, including two traditional statistical methods and three causal inference methods, Wu and colleagues derived broad evidence consistent with a causal link between long-term particulate exposure and mortality. Modeling a 10 μg/m3 decrease of fine particle concentration between 2000 and 2016 resulted in a 6% to 7% decrease in mortality risk. Based on their model results, the researchers estimated that more than 140,000 lives might have been saved if the current U.S. standard for fine particle concentration had been lowered to 10 μg/m3 between 2007 and 2016.
The authors included additional analyses focused on causation, which address criticisms that traditional analytical methods are not sufficient to inform revisions of national air quality standards. The new analyses enabled the researchers, in effect, to mimic a randomized study–considered the gold standard in assessing causality–thereby strengthening the finding of a link between air pollution and early death. The authors emphasize the urgent need to modify particulate concentration levels to help protect elderly individuals with respiratory diseases living in polluted areas. Particulate pollutants are alreas harmful for an averagely healthy person without particular health concerns. Go figure how the damage increase exponentially by increasing with age and the additional risk one is exposed by adding a couple of medical conditions. Averagely, after 65-year old, 1 in 3 persons is affected at least by high blood pressure, diabetes and respiratory defaillances due to cigarette smoking or asthma and the like. Pandemic has taught us that elders are already more vulnerable, mostly for their cardiological and diabetic condition.
Dr. Francesca Dominici, study corresponding author, American Association for the Advancement of Science, Clarence James Gamble Professor of Biostatistics, Population, and Data Science, is working by publishing data and awareness of how being close to manifacturing areas may increase, and more than significantly, the risks for the human health. She commented: “The Environmental Protection Agency has proposed retaining current national air quality standards. But, as our new analysis shows, the current standards aren’t protective enough. Our findings provide the strongest evidence to date that current national air quality standards aren’t sufficiently protective of Americans’ health. With the public comment period for the EPA proposal ending on June 29, we hope our results can inform policymakers’ decisions about potentially updating the standards. Besides, in the middle of a pandemic that attacks our lungs and makes us unable to breathe, it is irresponsible to roll back environmental policies”.
- Edited by Dr. Gianfrancesco Cormaci, PhD; specialist in Clinical Biochemistry.
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Wei Y et al., Dominici F, Schwartz JD. Brit Med J. 2019 Nov 27; 367:l6258.