New Research Finds Air Pollution is Far Deadlier than Previously Thought

June 29, 2017, 4:41 PM EDT

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Above: A factory smoke stack near the Delphi Chassis System Needmore Road Operations factory in Dayton, Ohio. Photo by J.D. Pooley/Getty Images.

The U.S. standards for our two deadliest air pollutants--ground-level ozone and fine particulate matter less than 2.5 microns in diameter (PM2.5 )--are not stringent enough to prevent thousands of premature air pollution deaths each year among the elderly, found a study by Harvard University scientists, led by Qian Di, released Wednesday in the New England Journal of Medicine. The research was exceptionally vast and lengthy, covering all 61 million Americans on Medicare, age 65 and older, for the thirteen years from 2000 to 2012.

The EPA’s National Ambient Air Quality Standards (NAAQS) sets the acceptable annual average concentration of PM2.5 pollution at 12 micrograms per cubic meter of air. However, the study discovered that PM2.5 concentrations as low as 5 micrograms per cubic meter caused significantly increased death rates, and found no “safe” level of PM2.5 below which the risk of death tapered off. In a press release accompanying the paper, the researchers said that if the level of PM2.5 could be lowered by just 1 microgram per cubic meter nationwide, about 12,000 lives could be saved every year. Similarly, if the level of ozone could be lowered by just 1 part per billion (ppb) nationwide, about 1,900 lives would be saved each year. The current EPA standard for ozone is 70 ppb for an 8-hour average; there is no annual average standard set for ozone, like there is for PM2.5 , and the researchers said that "our results strengthen the argument for establishing seasonal or annual standards" for ozone.

“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,” said Joel Schwartz, professor of environmental epidemiology at Harvard and the study’s senior author.

A massive death toll from air pollution

Death certificates never list air pollution as the cause of death. Nevertheless, air pollution is a huge and silent killer: about 3 million premature deaths per year globally are due to outdoor air pollution. Between 91,000 and 100,000 air pollution deaths per year occur in the U.S., according to separate studies done in 2016 by the World Bank and the Health Effects Institute (a U.S. non-profit corporation funded by the EPA and the auto industry.) Even higher U.S. air pollution deaths in excess of 200,000 per year were estimated for 2005 in a 2013 MIT study.

Air pollution deaths are calculated using epidemiological studies, which correlate death rates with air pollution levels. Air pollution has been proven to increase the incidence of death due to stroke, heart attack and lung disease. Since these causes of death are also due to other factors—such as life style and family history—we typically refer to air pollution deaths as premature deaths. A premature air pollution-related death typically occurs about twelve years earlier than it otherwise might have, according to Caiazzo et al., 2013.

Benefits of cutting air pollution far exceed the costs

The research comes at a time when many Republicans and the Trump administration are actively pursuing efforts to increase the amount of air pollution, potentially reversing decades of remarkable progress in cleaning our air which has saved tens of thousands of lives. As I explained in detail in a March post, Trump issued an executive order designed to undo the EPA’s Clean Power Plan, which aimed to reduce pollution from power plants. His June announcement that the U.S. would pull out of the Paris Climate Accord was a further blow to hopes for a cleaner atmosphere.

The cost to industry was given as the primary reason for these actions. However, a full cost-benefit analysis does not support this rationale. For example, the EPA estimates that annual costs to industry of the Clean Power Plan will be $1.4 - $2.5 billion in 2020, increasing to $5.1 - $8.4 billion per year in 2030. These estimates factor in the costs of investments in transitioning to lower-carbon electricity options and the savings that result from investments in energy efficiency. Electricity bills are predicted to rise modestly by 2.4 to 2.7 percent in 2020, but then decline by 2.7 to 3.8 percent in 2025, and 7 to 7.7 percent in 2030 as investments in energy efficiency pay off.

The public health and climate benefits of the Clean Power Plan are worth an estimated $34 billion to $54 billion per year in 2030, far outweighing the costs, the EPA estimates. Burning fewer fossil fuels will create less air pollution, and air pollution from the power generation industry will fall about 25% by 2030 if the Clean Power Plan is adopted. The EPA projects that the reduction in pollution will prevent up to 3,600 deaths, 1,700 heart attacks, 90,000 asthma attacks in children, and 300,000 missed work and school days per year by 2030.


In a New Engalnd Journal of Medicine editorial that accomanied Wednesday's research paper, the authors note that in explaining his withdrawal from the Paris climate agreement, Trump stated, “I was elected to represent the citizens of Pittsburgh, not Paris.” Ironically, Pittsburgh is less than 30 miles from the Donora Smog Museum, where a sign reads, “Clean Air Started Here.” Denora is the site of one of America's deadliest air pollution disasters, an October 1948 episode when smog from a zinc plant and a steel mill, both run by the United States Steel Corporation, settled over the town, sickening thousands and killing at least 20 people. The editorial concludes, "With the report by Di et al. adding to the large body of evidence indicating the risks of air pollution, even at current standards, we must redouble our commitment to clean air. If such protections lapse, Americans will suffer and we are doomed to repeat history. Do we really want to breathe air that kills us?"

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

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Dr. Jeff Masters

Dr. Jeff Masters co-founded Weather Underground in 1995 while working on his Ph.D. in air pollution meteorology at the University of Michigan. He worked for the NOAA Hurricane Hunters from 1986-1990 as a flight meteorologist.

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