The California Air Resources Board (CARB) is a group of grown-ups that works to make sure the air you breathe in California is clean and healthy for you to inhale. Think of them like the grown-up version of a superhero team, but instead of fighting bad guys, they're working to protect the environment and the people who live in it.
You know how sometimes when you run around or ride your bike, you might get out of breath? That's because you're breathing in air, and sometimes the air has yucky things in it that make it hard to breathe. CARB makes sure that grown-ups who are in charge of big machines, like cars and factories, don't make too much of these yucky things that hurt the air quality.
CARB does this by making rules and laws that companies and people have to follow, so they don't create too much pollution. They also check the air quality and make reports to tell people how good or bad the air is. If the air is bad, they tell people how to stay safe and healthy.
So, think of the California Air Resources Board like the grown-up superheroes who make sure that the air you breathe is clean so that you can continue to run around and play outside without getting sick.