There’s a clear link between exposure to particulate air pollution and premature death, going by the findings of a new study examining the Medicare claims of 60 million US citizens age 65 and older.
Considering the sheer scale involved here, covering around 97% of people age 65 and older in the US, the findings seem to be pretty damning — those exposed over the long term to airborne fine particulate matter (PM2.5) and ozone have experienced a much increased risk of premature death.
What’s really notable, though, is that this increased risk of death is present even in those whose long-term exposure was at levels below the National Ambient Air Quality Standards (NAAQS) currently established by the US Environmental Protection Agency (EPA).
So, in other words, here’s yet more evidence that “safe” levels of exposure to a common form of pollution are in fact nothing of the sort. Considering the vast increase in recent decades of the rates of various types of cancers, developmental disorders, and other diseases, the fact that “safe” levels of exposure to various pollutants and chemicals aren’t in fact “safe” shouldn’t be too surprising.
The last century or so has essentially been an enormous uncontrolled experiment where large numbers of highly novel substances have been deployed (intentionally or unintentionally) on a large scale without any real regard to their eventual effects on humans and on the wider environment. Long-term effects on individuals and also on future generations have generally been dismissed as impossible or unimportant — after all, “why not enjoy the party” — hence the situation that we are now in with a highly polluted and diminished world.
With regard to the new study, here’s more, from the press release: “The researchers examined Medicare claims records of 60 million Americans 65+ over a seven-year period, representing 460 million person-years of follow-up. They also estimated air pollution levels at each 1 kilometer grid for the entire US upon which the claims data could be overlaid and interpreted.
“To do this, the Harvard Chan researchers leveraged the results of an exposure prediction model developed by doctoral student Qian Di and Joel Schwartz, professor of environmental epidemiology and the study’s senior author. The exposure prediction model leverages satellite-based measurements and a computer simulation of air pollution.
“By relying on this well-validated prediction model, the team was able to include subjects who live in unmonitored and less-populated areas so that the effects of air pollution on all 60 million people could be analyzed regardless of whether they lived in urban, suburban, or rural areas.”
The principal investigator of the new study, and also professor of biostatistics at Harvard Chan School and co-director of the Harvard Data Science Initiative, Francesca Dominici, commented: “This is a study of unprecedented statistical power because of the massive size of the study population. These findings suggest that lowering the NAAQS for fine particulate matter will produce important public health benefits, especially among self-identified racial minorities and people with low incomes.”
Researcher Joel Schwartz commented as well: “This study shows that although we think air quality in the United States is good enough to protect our citizens, in fact we need to lower pollution levels even further.”
Notably, the researchers also found that, if PM2.5 levels could be lowered by even just 1 microgram per cubic meter (ug/m3) nationwide, around 12,000 fewer premature deaths a year would occur. The situation with ozone pollution was found to be similar — with a drop of even just 1 part per billion (ppb) nationwide, associated yearly premature deaths could be reduced by around 1,900.
Will even just the recommended reductions be achieved anytime soon? Considering that air pollution problems are continuing to grow in many US cities, mostly as a result of a growing population, the answer is probably “no.” Over the mid-term, though, negative economic changes could well result in reduced personal car use, which would definitely help to reduce local air pollution levels in many cities.
Other possible changes that would help quite a lot would be improved emissions controls for diesel semi trucks and/or an increasing market share for electric vehicles. All-electric semi truck shipping, though, doesn’t look too likely to be achieved anytime soon — which means that if air pollution in many of the urban parts of the US is really going to be reduced to a critical degree, then there will likely need to be a fundamental restructuring of the way that shipping and distribution occurs in the country.
The new study is detailed in a paper published in the June 29, 2017, issue of the New England Journal of Medicine.
Image courtesy US EPA