Wonder why hay fever is common during spring time? Researchers from the University of Iowa discovered that pollen particles remain suspended airborne for as many as eleven hours after it rains. They say that the granules could possibly exacerbate allergies if they make their way into the lungs.
The researchers base their findings using direct measurements of pollen fragment concentrations during and after spring rains of a range of severities in the spring of 2019.
The study's findings reveal that although pollen grains decrease significantly during rain, peak concentrations of submicron pollen fragments arise during rain events and then go on for several hours.
Elizabeth Stone, an associate professor in the Department of Chemistry and author on the paper, advised that pollen-sensitive individuals should avoid going outdoors during rain events, especially during thunderstorms, and for several hours following the rain episode.
Stone and her team decided to test the results of earlier research by directly measuring pollen from occurrences of rain in Iowa City between April 17 and May 31, 2019. During this period of peak tree pollen season, light showers, thunderstorms, and even a tornado occurred. Furthermore, the researchers recorded rain for a total of 28 days.
The findings of the study were published this month in the journal Environmental Science & Technology Letters.
Also Read : How to Minimize the Misery of Allergy Season
What are Pollen Allergies and How Can you Prevent Them?
According to the Asthma and Allergy Foundation of America (AAFA), pollen is among the most common generators of seasonal allergies. Many people know pollen allergy as "hay fever," while medical professionals usually refer to pollen allergy as "seasonal allergic rhinitis."
In all the seasons except for winter, plants release tiny pollen grains to fertilize other plants of the same species. Most allergy-causing pollen originates from grasses, weeds, and trees. These plants produce small, light, and dry pollen grains that are blown by the wind.
Experts advise pollen-sensitive people to limit their outdoor activities when pollen counts are high. Furthermore, it also helps to keep windows closed during pollen season to avoid accidentally inhaling pollen that could wander off near your location.
Additionally, the AAFA also advises limiting close contact with pets that spend some time outdoors. If you need to go outdoors, change your clothes immediately and take a shower to wash off particles of pollen that may have gotten into your clothes or hair.
About the Rain and Pollen
Pollen grains are tough but can rupture when exposed to high humidity. This is common during rain spells when a storm's drift carries the grains to the cloud base, where moisture can be quite high. Falling rain and the storm's downward breeze, then sling back the fragments toward the surface.
The researchers say that after the rain, pollen fragment clusters remain elevated from 2.5 to 11 hours. They add that longer times are correlated with the most torrential rains.
The team of researchers measured the highest concentration of pollen fragments during a morning storm on May 18. They gathered information on a peak concentration at 1.3 million pollen fragments per cubic meter of air. The next episode they captured was on May 24, with 960,000 pollen fragments per cubic meter of air.
Additionally, the AAFA says that rain can cause issues for those with allergies to grass, weeds, dust, and mold. In an event where rain pours when weed and grass pollen is high, raindrops can forcibly hit the ground and break up wads of pollen into smaller particles.
They then scatter quickly, which causes a sudden escalation in allergy and allergic asthma symptoms during the rain shower. Experts say that this tends to happen more during sudden, heavy downpours.
Read Also: Anxiety Sufferers May Experience Frequent Pollen Allergies, Study Says
