MedicalResearch.com Interview with:
Qian Di, M.S, Doctoral Student
Department of Environmental Health and
Francesca Dominici, Ph.D.
Principal Investigator of this study
Professor of Biostatistics
co-Director of the Harvard Data Science Initiative
Harvard T.H. Chan School of Public Health
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: The Clean Air Act requires Environmental Protection Agency to set National Ambient Air Quality Standard (NAAQS). Currently the annual NAAQS for PM2.5 is 12 microgram per cubic meter; and there is no annual or seasonal ozone standard. However, is current air quality standard stringent enough to protect human health? This is our main motivation.
We conducted the largest attainable cohort study, including over 60 million Medicare participants, to investigate the association between long-term exposure to ozone/PM2.5 and all-cause mortality.
We found significant harmful effect of PM2.5 even below current NAAQS. Each 10 microgram per cubic meter increase in PM2.5 is associated with 13.6% (95% CI: 13.1%~14.1%) increase in all-cause mortality. For ozone, 10 ppb increase in ozone exposure is associated with 1.1% (95% CI: 1.0%~1.2%) increase in mortality. Also, there is no appreciable level below which mortality risk tapered off. In other words, there is no “safe” level for PM2.5 and ozone.
In other words, if we would reduce the annual average of PM2.5 by just 1 microgram per cubic meter nationwide, we should save 12,000 lives among elder Americans every year; 5 microgram — 63,817 lives every year. Similarly, if we would reduce the annual summer average of ozone by just 1 ppb nationwide, we would save 1,900 lives every year; 5 ppb — 9537 lives.
Besides, we found black people, males and people of low SES are more vulnerable to air pollution.
MedicalResearch.com: What should clinicians and patients take away from your report?
Response: There are several take-away points: first, current NAAQS is not stringent enough to protect public, below which PM2.5 still imposes considerable burden of mortality. Second, it is imperative to set up annual or seasonal ozone standard, since we found long-term exposure to ozone is associated with increased mortality. Third, marginalized and disadvantaged people are more vulnerable to air pollution than general population.
We are providing bullet proof evidence of increased risk of deaths due to polluted air in the US. Even at levels below the safety standards.
As an editorial accompanying our paper and written by the NEJM editors states: “In March, President Trump signed an executive order….(to begin) a process to dismantle guidelines aimed to reduce emissions from coal-fired electricity plants. While the intent of the order was to undo regulations enacted by the Obama administration to slow climate change, the potential immediate consequences also include increasing particulate matter exposure and exposure to other harmful pollutants.”
The target audience is EVERYONE, everyone must breath, regardless whether you are rich or poor, regardless your race, religious affiliation and political party.
We hope that the general audience will understand that breathing clean air is a human right and a responsibility of our government. The discussion regarding climate change is not only about glaciers and heat wave disasters 100 years for now, it is also about breathing toxic air now.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: Since the overall association between air pollution and human health has been well-documented since the landmark Harvard Six Cities Study. We advocate that it is time to usher a new era. More attention is needed on people of color, disadvantaged groups, other marginalized groups. We need to study the social equality issue underlying air pollution-health association and understand the mechanism that social inequality translates into greater health risk in face of air pollution.
With all the talk about the effects on global climate change of President Trump’s decision to withdraw from the Paris climate accord, the fact that air pollution is killing thousands of Americans today – not in some far distant future – is lost.
The answer is not to loosen air quality standards that save American lives. It is not to return to the heyday of coal-burning power plants. It is not to discourage investments in wind, solar, and other non-fossil fuels.
My key point is: Make no mistake. We need to strengthen, not weaken, EPA air pollution standards. We need to increase, not reduce the EPA research funding.
MedicalResearch.com: Is there anything else you would like to add?
Response: This work was made possible by the support from the NIH grant R01 ES024332-01A1, ES-000002, ES024012, R01ES026217, P50MD010428, 4953-RFA14-3/16-4; NIH/NCI grant R35CA197449; HEI grant 4953-RFA14-3/16-4, and USEPA grants 83587201-0, RD-83479801. The contents are solely the responsibility of the grantee and do not necessarily represent the official views of the funding agencies. Further, funding agencies do not endorse the purchase of any commercial products or services related to this publication. The computations in this paper were run on (1) the Odyssey cluster supported by the FAS Division of Science, Research Computing Group at Harvard University; (2) the Research Computing Environment supported by the Institute for Quantitative Social Science in the FAS Division of Social Science at Harvard University.
MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.
Qian Di, M.S., Yan Wang, M.S., Antonella Zanobetti, Ph.D., Yun Wang, Ph.D., Petros Koutrakis, Ph.D., Christine Choirat, Ph.D., Francesca Dominici, Ph.D., and Joel D. Schwartz, Ph.D.
N Engl J Med 2017; 376:2513-2522
June 29, 2017DOI: 10.1056/NEJMoa1702747
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