Robert covered the air pollution problem here. Its real. In addition to that issue there is one category I would like to shop that is unavailable - NT's ventless heaters. We can buy Reznor-type garage heaters and horizontal salamander units but nothing unvented can be installed in living space here. I think this is a safety rule.
This chart illustrates that. In summary it says highest 10% for health risks, and for nearly all categories of pollution.
My understanding is a little different. The ocean off Northern California holds at 54 degrees because the currents come down from Alaska. And all the weather blows in from the west. As the land inland warms in summer, the warm air rises, and this sucks in cool ocean air though the Golden Gate. (and brings SF smog inland). But I've never noticed the breathing effect you mention, with air moving west part of the time. I think the general trend is for weather moving east, both rainclouds and smog, to stack up against the Sierras with only the high-altitude clear dry air going over the summit into the Nevada desert and beyond.
1650 ft elevation, east of Sac. That smog layer goes up to about 3000', or about the town of Camino, as you head form Sacramento to Lake Tahoe.
