For fine particulate matter, which has a legal limit of 12 micrograms per cubic meter of air, they found that seniors faced an increased risk of premature death when exposed to as little as 5 micrograms per cubic meter, the lowest amount they measured.
– Just because air pollution falls below legal limits does not mean you're safe. Indeed, there is no "safe" level of air pollution as pollutants cause an increased risk of premature death even when detected at a fraction of the legal limit set by the EPA, a new study finds. "We are now providing bullet-proof evidence that we are breathing harmful air. Our air is contaminated," Francesca Dominici, the lead author of the Harvard study published in the New England Journal of Medicine, tells NPR. Researchers used a computer model to assess levels of ozone and fine particulate matter by US zip code, then determined what effect the pollutants had on one’s risk of premature death using data on 97% of Americans 65 or older, reports the Los Angeles Times. The risk of death climbed when seniors were exposed to as little as 5 micrograms of fine particulate matter per cubic meter of air, though the legal limit is 12 micrograms. Researchers found lowering the limit to 11 micrograms would save 12,000 lives per year. Similarly, the risk of death grew with exposure to ozone at 30 parts per billion; the EPA limit is 70 parts per billion. Researchers found cutting the legal limit to 69 parts per billion would save 1,900 lives annually. However, an editorial accompanying the study notes the Trump administration is favoring policies that would give us "dirtier air" which is "going to kill a lot of people." Trump ally Scott Segal counters that environmental rules can also "adversely affect public health" by increasing health care costs, per NPR. (Perhaps we need a forest city.)