On a visit to Tucson, Ariz., my allergies caused me great problems. I thought air there was pollen-free.
The pristine and pollen-free desert air of Tucson is a thing of the past. Tucson’s air is now highly charged with pollen from non-native plants that have been introduced into the area since the 1940s. Much of the native desert vegetation of the region was insect-pollinated, and those plants released little pollen. But since the 1940s, Bermuda grass, Chinese mulberry trees and other non-native pollen-producing plants have been introduced. This vegetation is wind pollinated, producing huge quantities of airborne pollen. The result is that Tucson’s pollen count increased ten-fold from the 1940s to the 1980s, and even more since then.