Which is better, Negative Ion, Ozone, or HEPA air filters?

Question:Which is better for removing smells and allergens from the air? Ion generators? Ozone generators? hepa air filters? Or some machine that is a combination of the three? I want to get something like an ionic breeze but not sure what's best.?

Answers:
HEPA, as long as you change the filters as directed. You don't see hazmat teams breaking out the ionic breezes on a cleanup.