There's a lot going on in Colorado's air this week, but what's least visible may be hardest to fight off.
Dr. Christine Cho is a pediatric allergist and immunologist at National Jewish Health. She specializes in respiratory, cardiac, immune and allergies.
"The pollen that causes allergies.. .you really can't see them with the naked eye," Cho said. "Again, they are windborne pollen. They are tiny and they can go for miles and miles with the wind. Usually if you can see pollen, it's typically not the pollen that causes significant allergies."
Dr. Cho says the effects from invisible tree pollen, oak, cottonwood and juniper are exacerbated by haze and smoke from nearby fires.
The Tinder Fire in Arizona is big enough it can be seen from space through satellite images from NASA via Colorado's DigitalGlobe.
Images show some of the smoke making its way into Colorado, but Cho says it's not the smoke causing discomfort.
"You can't be allergic to smoke," Cho said. "It can have an irritant affect that can look a lot like allergy symptoms."
The big cause for allergies right now is tree pollen.
Over the summer there's grass pollen, and during the fall, weed pollen. During the winter there's no pollen, but pets may trigger allergies.
