Pollen wars

Forrest M. Mims III

Spring and fall can be uncomfortable seasons for people who suffer with asthma and allergies.

The Environmental Protection Agency (EPA) blames this problem on ozone in polluted air. But spring and fall respiratory problems are caused mainly by pollen, not ozone. The EPA does not know this, for they measure ozone and not pollen.

Some 112 ozone monitors in Texas provide hourly data to the EPA. Only 7 pollen stations in Texas report daily summaries to the network operated by the American Academy of Allergy, Asthma and Immunology (AAAAI).

One day last week I awoke with a sore throat and mild dizziness. While walking to the office near my home, a sudden gust of wind pushed a strange, yellowish cloud over the roof of our house.

The cloud resembled smoke, but it was pollen! Our old pickup was completely coated with a yellowish powder.

Was ragweed pollen the culprit?

A few days before I declared war on the ragweed in our field and mowed it down. But that was impossible with the stands of giant ragweed down at the creek, all of which were about to bloom.

I used a microscope slide to scrape some pollen from the windshield of the pickup and examined it with our daughter Sarah's microscope.

Ragweed pollen resembles spheres covered with dozens of tiny spikes. Just looking at them makes you want to sneeze.

But the sample from the windshield had only a few ragweed grains. Nearly all the grains were cedar elm (Ulmus crassifolia) pollen.

Cedar elm flowers are small and hardly noticeable. So I pulled a branch down for a close look. It was covered with tiny flowers loaded with yellow pollen. Clearly it was the cedar elm pollen that had caused my symptoms.

People who experience serious reactions to pollen need to know when to take precautions. So they need to know when the pollens that bother them are floating in the air.

Many television stations report pollen counts. But some of these "counts" are actually forecasts instead of actual pollen counts.

Students looking for a good science fair project might consider studying pollen. It's easy to collect, and it can be examined with an inexpensive microscope. Many web sites have photographs of pollen that can help students identify what they find.

Based on my daughter Sarah's experience studying smoke, dust and molds, students who study pollen will also find lots of other stuff floating in the air, including insect fragments, spider silk, plant detritus and fungal spores.

Forrest M. Mims III and his science are featured online at www.forrestmims.org.

This feature was originally published in Forrest Mims's weekly science column in the Seguin Gazette-Enterprise, Seguin, Texas. The column is written for a general audience.