Air pollution causes premature death — definitive new Harvard study

A new study from Harvard University’s T.H. Chan School of Public Health, published in Science Advances, provides strong evidence of the causal link between long-term fine particulate matter (PM2.5) exposure — air pollution — and premature death rates. The study provides the most comprehensive evidence to date.

Researchers looked at 16 years’ worth of data from 68.5 million Medicare enrollees — 97% of Americans over the age of 65 — adjusting for factors such as body mass index, smoking, ethnicity, income, and education. They matched participants’ zip codes with air pollution data gathered from locations across the US. In estimating daily levels of PM2.5 air pollution for each zip code, the researchers also took into account satellite data, land-use information, weather variables, and other factors.

Based on that finding, the researchers estimated that if the US lowered its annual PM2.5 standard to 10 μg/m3 — the World Health Organization’s annual guideline — the US would save 143,257 lives in one decade — a 6-7% decrease.

So what should the Environmental Protection Agency do (EPA), in light of that new information? Further tighten its standards. But that’s not what the EPA is doing.

On April 14, the EPA announced that it would not work to lower levels of particulate matter, thus not further reducing air pollution, despite the recommendations of its own scientists to continue to strengthen the standards set previous to 2016 — and put the country on the path to saving lives.

Doctoral student Xiao Wu, co-author of the study, said:

Our new study included the largest-ever dataset of older Americans and used multiple analytical methods, including statistical methods for causal inference, to show that current US standards for PM2.5 concentrations are not protective enough and should be lowered to ensure that vulnerable populations, such as the elderly, are safe.

A former EPA scientist’s opinion

Electrek spoke to John Bachmann, former associate director for science/policy and new programs, EPA Office of Air Quality Planning and Standards, about these new findings. Bachmann said:

This nationwide study is easily the most sophisticated and comprehensive air pollution epidemiology study to date.

It provides strong and causal evidence that addresses all the major potential ‘confounders’ that the administrator [Andrew Wheeler] and his Clean Air Scientific Advisory Committee (CASAC) advisers raised in the rationale for not strengthening the standards.

It’s an example of the rare ‘silver bullet’ study, the implications of which simply cannot be ignored. And yet it fits well with conclusions reached by many traditional epidemiology studies over the last two decades.

Based on studies, EPA staff and CASAC considered both the EPA policy assessment, and a 20-member Independent PM Research Panel (IPMRP) — which was disbanded by the EPA — recommended the standards be revised. The IPMRP believed the level of the current standards should be reduced from 12 ug/m3 to a range of 10 to 8 ug/m3. Yet this study, supported by a number of other newer studies, compel a standard no higher than 8 ug/m3, and possibly even lower.

The EPA banned independent panels, but a judge reversed that decision in April, saying that the EPA failed to provide a “reasoned explanation” for doing so. The EPA won’t fight the reversal.