Some TREES have been found by botanists to produce pollen during this season.
- Arizona Cypress
- Utah Juniper
Although not a true allergen, wood smoke from fire places and wood stoves can be present through most of the winter months in Flagstaff. Smoke can be irritating to those with hayfever and asthma or breathing difficulties.
Mold spores can be present year round as well; however, are more prominent during seasons with more moisture and wind.