If he lives in the valley between the Uinta and the Wasatch mountains (so SLC area) then yes, they get some pretty good temperature inversions that trap air pollution in the valley. Still, what they consider bad wouldn't even budget the needle here in LA.

I personally prefer cycling specific outerwear because it tends to fit slimmer, flaps less in the wind and has longer arms and back (My arms are pretty long as it is, leaning forward exacerbates it.) If you think in terms of layers, you can probably find some nice hiking gear that will be suitable as well in terms of weight and breathability.