Is the smoke from the western wildfires affecting your region of the country?

  (it’s its)

  With the apostrophe, it is a contradiction of two separate words, which in the context of your sentence, does not make any sense at all. When the contraction is broken down and the apostrophe removed:

it is
it has

. . . wending it is way . . . 
. . . wending it has way . . .

Therefore, the only proper, correct, and appropriate word for this situation is the possessive pronoun its, because the action of wending is being carried out by the smoke.

The eagle spread its wings.
Our team won its first two games.
If its axle is damaged, don’t drive it.
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  Thank you, I have learned a new word and I stand corrected. 

wending

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