As a rule of thumb, people with hay fever may want to avoid going outside after 2pm. A new study released this week found that pollen counts tend to be lowest during the morning hours and highest during mid-afternoon into the late evening.
Researchers in Atlanta conducted the study, using a recently developed device meant to measure pollen concentrations by taking automated and real-time images of collected air. Their earlier research found that this device is roughly as accurate as the current gold standard for measuring pollen, which involves manually counting pollen grains collected by a sampling device left outside. They placed their sensors at three different locations in and around Atlanta, collecting measurements throughout the last week of March 2021.
On average, they found that pollen counts tended to be highest from 2pm to 9pm, and lowest from 4am to noon. The team’s findings were presented this week at the American College of Allergy, Asthma and Immunology (ACAAI)’s Annual Scientific Meeting.
The study’s results have not been published in a peer-reviewed journal, so they should be viewed with some added caution. And it’s known that different types of pollen can become more of a nuisance during different times of the day at different periods of the year. According to the ACAAI, for instance, pollen levels are thought to be highest in the evening during the spring and summer when tree and grass pollen is most common, while they’re thought to be highest in the mornings during late summer and early fall when ragweed is most common. But the study’s lead author Stanley Fineman, an allergist at Emory University, believes that their findings might be able to provide some guidance to people with these allergies.
“People who have pollen allergies can generally benefit from knowing at what times of day pollen counts are highest,” said Fineman in a statement provided by the ACAAI.
Regardless of when, exactly, pollen is most abundant, there are practical steps you can take to reduce your exposure to it, the authors note.
“I see patients every spring and fall who are really suffering due to their pollen allergies,” said Fineman. “There are ways to diminish the impact of pollen during allergy season, including closing windows and taking off shoes and pollen-laden clothes when you walk in your door, and immediately throwing your clothes in the washing machine. If you are someone who enjoys outdoor activities, you need to be aware of when pollen counts are lowest, and what times are best for you to be outside. Weather apps and websites are a good way to monitor pollen levels in your area.”
Unfortunately, this advice will only be more relevant over time since pollen seasons are expected to become longer and more intense in the years to come, thanks in no small part to climate change.