The Trump administration is considering rolling back several Environmental Protection Agency air pollution regulations, including those that govern ozone. The move could have severe air quality implications in Phoenix.
The EPA is considering eliminating the so-called "endangerment finding," developed in 2009 to measure the health impacts of greenhouse gases.
The Sierra Club Grand Canyon Chapter's Director Sandy Bahr said that's significant in Phoenix, which already suffers from dangerous levels of ozone generated by traffic.
"In Phoenix, the ozone levels are high," said Bahr. "They exceed the health-based standards for ozone. And so there has been an effort to get around that, so Phoenix isn't bumped up from moderate to serious, because our ozone pollution is serious."
Arizona is also home to 203,000 dairy cows at concentrated animal feeding operations, which are known to pollute nearby air and groundwater with manure runoff and methane emissions.
Bahr said while the rollbacks haven't yet taken effect, they threaten Arizona residents on a number of fronts.
"There are multi-leveled attacks on environmental protection," said Bahr. "Our air, our water, the land, our health, all being attacked by this administration and rolling back important protections, some of which we've relied on for decades."
Another proposal being considered by the Trump administration would repeal greenhouse gas emission standards for fossil fuel-fired power plants.