Valley air quality

This article talked a lot about the air quality in the Central Valley. A local football coach mentions that many of his players are using inhalers because they can't breathe and the fact that they have to change practice times during bad air days. He remembers being able to see the Sierra Nevada mountains, but passenger vehicles and trucks moving farm products through the valley have really changed things here.California sets tougher emissions standards than national standards. A California air regulator is ready to fight the president's pollution standards, and would like to see flexibility for automakers.

https://www.usatoday.com/story/money/cars/2018/04/16/emissions-fight-pits-california-against-detroit/519587002/