Rain should mark end to the sneezy season

If your nose had been driving you nuts with all that itching and all those sneezes that come with it, maybe you were glad to see the rain Tuesday, which washed away much of the pollen in the air. Consider yourself lucky: It was only the seventh time since 1931 that it rained on July 12 in Eugene-Springfield.

The good news for allergy sufferers is that Tuesday’s moisture should signal the end of a late but nasty allergy season, said Dr. Kraig Jacobson, medical director of the Allergy and Asthma Research Group, the research arm of Oregon Allergy Associates in Eugene.

“People are going to start feeling better,” Jacobson said Tuesday.

Rain cleanses the air and drops the grass pollen count, he said, and the grass pollen season has now pretty much run its course this summer.

After this season’s highest pollen count — 532 grains of grass pollen per cubic meter — on July 1, and another spike in the 300s (anything over 200 is considered very high) on July 4 and July 5, measurements fell steadily, dropping all the way to 16 on Monday. The measurement taken at 7 a.m. today for the previous 24 hours probably will be even lower than that, Jacobson said.

The onset of this year’s grass pollen allergy season was delayed by one of the coldest, wettest springs on record in Oregon. But once the rains ceased, pollen counts soared in early June.

Wet springs like this year’s and a similar one in 2010 can cause pollen fragmentation, Jacobson said. Pollen gets laden with starch and protein and when it’s released in the air, it breaks apart and can penetrate deeper into the lungs and cause more severe cases of asthma and allergies, he said. Fragmented pollen doesn’t show up in pollen counts, Jacobson said. There’s currently no way to measure it, although Oregon Allergy Associates, the only National Allergy Bureau-certified pollen counting station in Oregon, is working with allergists at the California Institute of Technology to try and quantify pollen fragments, he said.

The center takes the tally from its pollen collection slides at 7 a.m. each day, reflecting the air quality of the previous 24 hours of air sampling, so Tuesday’s 7 a.m. count of 16 grains reflected conditions between 7 a.m. Monday and 7 a.m. Tuesday.

The pollen is collected using a Burkard air sampler located on the office’s second story. A vacuum pump pulls air through a small port that is directed into the wind. The air lands on a greased microscope slide inside the air sampler’s cylinder.

July 4 normally marks the end of the grass pollen allergy season, but the delayed start this year caused the pollen season to run until July 11, Jacobson, said.

But Jacobson cautioned that what happened last September and October could repeat itself this year. A wet 2010 spring caused an accumulation of ground moisture, which caused a “resprout” of grass in the summertime, Jacobson said, generating pollen in the early fall.

His advice: Take your medication. And if it’s really bad, consider allergy shots.

“For people looking ahead, this is the time we really get busy,” Jacobson said.