"As I record this episode. It is spring. It's arguably the most beautiful time of the year whether turns warmer festivals around the world, celebrate the season and the blooming of the trees and flowers at brings. It's just a great time to be alive in less. You are one of the fifty million Americans who has allergies while you probably know that pollens to blame for your congestion burning eyes and scratchy throat, there's a lot more to these little grains, which are actually hard at work at fertilizing plants, although most allergies are caused by airborne pollen. Not all of that is allergy Nick certified experts around the world count. Identify pollen grains, often on a daily basis. So that those with allergies can know what's floating around outside and how much of it. There is pollen looks like powder because it consists of lots of tiny grains. These grains are the male Demidov fights of plants that produce seeds these cranes can be as small as ten micrometres or as LA. As one hundred micrometres, which still means they're all microscopic, just a fingertip full collected from the hood of your car could contain thousands of pollen, grains, these tiny, grains, which produce sperm are needed for fertilization. We spoke with Dr Stelle Levitan professor and chair of biological science. At the university of Tulsa, she's also a member of the arrow biology committee that oversees the national allergy bureau, which is part of the American Academy of allergy, asthma and immune -nology Levitin explains without pollen. We wouldn't have seeds or fruit or grains in flowering. Plants pollen must be transported from the male parts of the plant the answers where the pollen is produced to the carpel the female part of the plant that produces the audibles pollen can be transported by animals like bees and butterflies or by the wind. Levitin said wind pollinated plants are small and inconspicuous and produce large amounts of lightweight. Pollen. That's easily carried by wind insect pollinated plants tend to be large and showy. They often have brightly colored pedals are fragrant and produce nectar generally airborne pollen is from those wind pollinated plants, and is the kind that attacks those of us with allergies. If you tuned into television weather forecast during pollen season, you'll likely hear people talk about the days pollen count. You maybe even wondered whether the count was some sort of estimate of quality, literally counting microscopic grains of pollen everyday might sound a little bit ridiculous. But that's actually just the beginning of what's happening. The pollen count is the number of pollen grains in cubic meter of air over twenty four hour period to measure it Polynice captured by volume metric air sampling instrument. There are two types of these instruments rotating arm impact is like the rotor odd, sampler and Hearst type sport traps like. The buck sampler, they're both volume you metric, but they operate on different principles and microscopic analysis is needed to analyze both types of samples. The rotating arm version has a head that spins two thousand four hundred revolutions per minute. While it spins to small greased rods dropped down capturing pollen and fungal spores. These rods are placed into a special microscope, adapter and examined the Hearst type instrument on the other hand has a section trap that sucks in air and particles that adhere to a greased microscope slide inside in this case the slide moves toward the intake orifice at two millimeters per hour. So it's possible to see what was swirling through the air hour by hour during examination. Using one of the volume metric air sampling instruments, some pollen station sample air and collect pollen three hundred sixty five days a year other stations run samples on weekdays or only collect three days a week. But not every city or town has the ability to count pollen and pollen stations are operated in a variety of ways, some are run by the city or county public health departments others by allergists, for example in metro Atlanta. A city with a lot of Greenspace in a notoriously high pollen count certified counters from Atlanta allergy and asthma get up early and physically count, the number of pollen particles on the glass slide from Hearst type instrument that's been outside for the prior twenty four hours. That number is what Atlanta residents may he reported by various news outlets. Levitin explained a few stations are run by academics. Like me who study airborne pollen as a research topic, it takes training to learn the morphology of pollen, and it takes time to analyze air samples certification"