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The EPA reclassified the Valley's ozone pollution as "moderate" last month, which is more severe than its previous ranking of "marginal."

Why it matters: Ozone is harmful to breathe. It aggressively attacks lung tissue, which can cause respiratory diseases, according to the American Lung Association.

Of note: The Phoenix area has significantly decreased the number of high ozone days since its peak in 2000.

Flash back: In 2015, the EPA tightened the ozone pollution standard to 70 part per billion, from 75.

What's next: The new classification requires the region to take more intense action to bring down ozone pollution.

Be smart: The Maricopa Association of Governments offers some tips for everyday residents to combat ozone pollution:

Go deeper: Phoenix wants 280,000 EVs on its streets by 2030

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