Unfortunately, the State of Arizona does not use a sliding scale. In other words, 1967 (I believe) and older vehicles are exempt. In states that use a sliding scale, this cutoff year is slid +1 every year
The only third gens that are exempt are ones who reside in the zip codes listed here:
http://www.azdeq.gov/environ/air/vei/exempt.html
and ones with classic car insurance, like mine. Then again, I drive mine less than 50 miles per year.... and I pass emissions anyways....