California's dirtiest air now has a new way to avoid federal pollution penalties
What happened
US environmental regulators are proposing to approve new rules for California's San Joaquin Valley. These rules change how the region proves it is meeting federal clean air standards for ozone pollution.
Why it matters
The San Joaquin Valley has some of the worst air quality in the US. For years, the region has struggled to meet federal ozone standards, leading to potential penalties. This change allows the region to use a different method to show it is making progress, potentially avoiding those penalties without necessarily cleaning the air faster. It shifts the focus from directly meeting a standard to demonstrating an effort to meet it.
The signal
Watch whether the San Joaquin Valley actually reduces its ozone levels, or if it simply uses the new rules to avoid penalties while air quality remains poor.