Linn County collects pollen counts for all of Eastern Iowa

CEDAR RAPIDS - Better days are ahead for seasonal allergy sufferers.

Data kept by Linn County Public Health since tallies began show few days past mid-September with high counts for ragweed or other plant pollens.

“Usually when it's hot and humid, it gets high,” said Amy Drahos, senior air quality scientist for the department. “By the end of September, it dies off dramatically.”

Drahos, one of the Linn County Public Health specialists who take daily pollen counts during weekdays, said rain, too, tends to “knock down” pollen, a larger particle than the fine particulate matter also tracked by the health department.

High-tech equipment captures sulfate levels and other pollutants from the top of Linn County's air quality monitoring station outside the health department's northwest Cedar Rapids office, but the pollen sampler is relatively simple.

Two tiny glass rods are coated with silicon grease to capture pollen from the top of the station.

The toaster-sized machine spins the rods for 30 seconds every 10 minutes during a 24-hour period.

Drahos and fellow senior air quality scientist, Tony Daugherty, examine the rods under a microscope to count ragweed - which appears as a jagged-edged circle - and other pollens.

The numbers are sent to the State Hygienic Laboratory, which forwards the counts for publication on the National Oceanic and Atmospheric Administration's National Weather Service website at www.crh.noaa.gov/dmx

Linn County is the only site that collects the information for Eastern Iowa. Other centers are located in Council Bluffs, Ankeny and Sioux City to cover the rest of the state.

The department also sends pollen counts to nearly 300 allergy sufferers, doctors and others who sign up to receive email notices.

Information recently has been provided on Linn County Public Health's Facebook page, as well, and via Twitter - @LCPublicHealth.

An estimated 36 million Americans suffer from seasonal allergies, also known as hay fever.

Pollen released by ragweed is the airborne allergen most responsible for the sneezing, itchy, watery eyes and other symptoms experienced at this time of year.

Daugherty said pollen counts this year are comparable to past years.

Numbers reflect how many grains of pollen are in each cubic meter of air.

Examination of data collected by the department since 1994 shows late August is typically the peak for ragweed.

Only once have counts in Eastern Iowa reached the very high level for ragweed, with a reading of 635 on Aug. 24, 1998.

The high range has ended by the second week in September all of the past 17 years except 2007, when the season kicked in late, on Sept. 5, and was still at 107 on Sept. 25.

Just two years later, however, no days in September reached the high level.

This week, the ragweed count was still high, at 111 on Tuesday, but had moderated to 24 by Wednesday.

Drahos said counts begin in August and end after the first hard frost, usually in late September or early October.

While just one part of their duties, the pollen counts hit home with Daugherty, an allergy sufferer.

“I can tell when it's really bad,” he said. “I sneeze a lot.”

John Miller, limnology supervisor for the Hygienic Lab's Ankeny office, said allergy sufferers can use the data as a tool to know when pollen counts are trending upward.

The “other” pollen counts refer to any number of plants besides ragweed, he said. “You pretty much name it and it's going to be in there.”

Miller said while Iowa's allergy season may seem severe to some, he has reviewed data for states such as South Carolina, where pollen counts can be three to nine times higher and the season lasts longer.

“Unless we get another hot spell, I don't think it will kick up again,” he said of Iowa's hay fever season. “There are much worse places to be.”