The United States Environmental Protection Agency (EPA) has yet to decide on a firm ozone standard for health, contemplating a range of between 65 and 70 “parts per billion (ppb) to better protect Americans’ health and the environment, while taking comment on a level as low as 60 ppb, the EPA wrote in “EPA Proposes Smog Standards to Safeguard Americans from Air Pollution,” a Nov. 26, 2014 news release. “The Clean Air Act requires EPA to review the standards every five years by following a set of open, transparent steps and considering the advice of a panel of independent experts. EPA last updated these standards in 2008, setting them at 75 ppb.”
For an in-depth and complete discussion on the issue, see: “Policy Assessment for the Review of the Ozone National Ambient Air Quality Standards,” available from the U.S. EPA Office of Air Quality Planning and Standards Health and Environmental Impacts Division, EPA-452/R-14-006, Aug. 2014 here.
I’m in the process of reading the document to get a greater understanding of what is involved and am currently about a fifth of the way through.
But briefly, “EPA scientists examined numerous scientific studies in its most recent review of the ozone standards, including more than 1,000 new studies published since the last update. Studies indicate that exposure to ozone at levels below 75 ppb – the level of the current standard – can pose serious threats to public health, harm the respiratory system, cause or aggravate asthma and other lung diseases, and is linked to premature death from respiratory and cardiovascular causes. Ground-level ozone forms in the atmosphere when emissions of nitrogen oxides and volatile organic compounds ‘cook’ in the sun from sources like cars, trucks, buses, industries, power plants and certain fumes from fuels, solvents and paints. People most at risk from breathing air containing ozone include people with asthma, children, older adults, and those who are active or work outside. Stronger ozone standards will also provide an added measure of protection for low income and minority families who are more likely to suffer from asthma or to live in communities that are overburdened by pollution. Nationally, 1 in 10 children has been diagnosed with asthma.” This is what the EPA in the aforementioned news release wrote.
Aside from this, establishing an ozone standard at a range of between 70 and 65 ppb, according to the EPA, will prevent between 320,000 and 960,000 asthma attacks; between 330,000 and 1 million missed days of school; between 1,400 and 4,300 asthma-related hospital emergency department visits; between 65,000 and 180,000 days of work missed; and over 750 to 4,300 early deaths.
“EPA estimates that the benefits of meeting the proposed standards will significantly outweigh the costs,” by a factor of 3 to 1 in terms of health benefits, as I understand it.
But, deciding on the correct standard at this point is what is at issue.
In the release the agency also notes that between 1980 and 2013, average ozone levels nationally have improved, dropping by a third.
“The Clean Air Act provides states with time to meet the standards. Depending on the severity of their problem, areas would have between 2020 and 2037 to meet the standards,” the EPA pointed out.
“The agency is also proposing to strengthen the ‘secondary’ ozone standard to a level within 65 to 70 ppb to protect plants, trees and ecosystems from damaging levels of ground-level ozone.”
In the final analysis, it remains to be determined what the health standards for ozone will be.
Image above: U.S. National Archives and Records Administration