On Oct. 1, 2015, the U.S. Environmental Protection Agency (EPA) announced it established a new uniform standard for both primary and secondary ozone, set at 70 parts per billion (ppb) each. The standard was lowered from the one set in 2008 by 5 ppb. This national ozone standard is averaged over a period of eight hours.
On Feb. 3, 2016, meanwhile, in “Group challenges newest ozone standard: What this is about,” I wrote: “As it happened, after eight years with National Ambient Air Quality Standards (NAAQS) for ozone averaged over eight hours set at 75 parts per billion (ppb) in 2008,
If our reporting has informed or inspired you, please consider making a donation. Every contribution, no matter the size, empowers us to continue delivering accurate, engaging, and trustworthy science and medical news. Independent journalism requires time, effort, and resources—your support ensures we can keep uncovering the stories that matter most to you.
Join us in making knowledge accessible and impactful. Thank you for standing with us!