Be sure to set the AC to "recirculate," and if it's not hot outside, you can keep it in filter-only mode. Using an air conditioner in your car can cut the amount of pollen you breathe by as much as 30%, says Myngoc Nguyen, MD, chief of allergy at Kaiser Permanente Medical Center, Northern California.
As seasons change, plants spew pollen. So try to anticipate and treat yourself before that happens. Same goes if you know you'll be visiting a cat-loving friend, and felines are your worst symptom trigger.