OK, I found the answer after digging through Sky Harbor's website. From the FAQs...
Is smoking allowed at Sky Harbor?
Answer: Smoking is allowed in designated cocktail lounges and restaurants in the gate areas at Sky Harbor. There is one smoking area per concourse at Sky Harbor. The airport also has two smoking lounges, one in Terminal 2, and one in Terminal 4. Smoking is also permitted outdoors in designated areas on the curbs.