The Environmental Protection Agency (EPA) on Wednesday declined to tighten air quality standards for smog, despite calls from environmental and health advocates for a stricter standard. 

The EPA finalized its decision to retain the Obama-era air quality standard for ozone, the main component of smog, of 70 parts per billion (ppb).

In the stratosphere, the ozone layer protects the Earth from ultraviolet light from the sun, but at ground level it can worsen health conditions like bronchitis, emphysema and asthma.

“This decision fulfills the Trump administration’s promise to streamline the [National Ambient Air Quality Standards] review process,” EPA Administrator Andrew Wheeler told reporters. 

Environmental advocates have called for tightening the standard to 60 ppb or lower, and have pointed to studies linking adverse health impacts of exposure to ozone at concentrations lower than the current standards. 

“Air pollution kills thousands of people each year and failing to set a more protective standard means that the health of millions of Americans is threatened,” said Paul Billings, the American Lung Association’s national senior vice president for […]