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The Trump administration has been holding public hearings this week on its plan to undo Obama era regulations. States like California are threatening to go to court. There is also concern in Arizona. Will Stone of member station KJZZ in Phoenix reports.
WILL STONE, BYLINE: It did not take long for Columba Sainz to notice the air quality after moving to Phoenix.
COLUMBA SAINZ: Seeing my daughter wheezing at night, waking up having trouble to breathe - it just gave us a red flag.
STONE: Sainz discovered the symptoms were, in part, tied to the pollution in her downtown neighborhood. And she began advocating, speaking to other families in the community.
SAINZ: We talk about cars. We talk about the quality of the air. We talk about climate change.
STONE: It's a conversation now happening across the country as the Trump administration moves to weaken the fuel efficiency standards for new cars. This could be a big problem for the Phoenix metro area. The desert valley struggles with pollution, and transportation is a major source. But Will Humble says it has been getting better.
WILL HUMBLE: Our particulate matter, ozone, carbon monoxide - if you go down the list, air quality is improving.
STONE: Humble is the former director of the Arizona Department of Health Services.
HUMBLE: One of the reasons why is because the efficiency of vehicles have been getting better.
STONE: In part, that's because of the fuel efficiency standards that took effect in 2012, which require new cars to get more miles per gallon. The standards are set to keep going up in the coming years. But the Trump administration hopes to freeze these increases after 2020. It argues the standards are driving up prices. And the proposed changes will let more consumers buy new, safer cars. Still, states like California are vowing to fight the effort in court. Arizona isn't doing that, but it is quietly opposing the changes. A letter from the state's head of air quality to the federal government cites concerns about high ozone levels - only projected to get worse in coming years.
RAM PENDYALA: It does hit close to home.
STONE: That's professor Ram Pendyala, who studies transportation at Arizona State University. He says the Obama-era standards have made a big difference in the car industry.
PENDYALA: It has spurred innovation. It has motivated auto manufacturers to invest in hybrid vehicles, more fuel-efficient engine technologies.
STONE: Automakers echoed this sentiment at this week's public hearing in Michigan, when executives from Ford and Fiat Chrysler said they're committed to making more fuel-efficient vehicles.
For NPR News, I'm Will Stone in Phoenix.
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