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What are seasonal allergies, and how can you get rid of them?

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What are seasonal allergies, how do they differ from household allergies, and can you prevent them? I learned all that and more from an expert!

woman blowing fluff off of a dandelion

Seasonal allergies

Recently I attended an event hosted by Honeywell, where they treated me to breakfast and an extremely informative session about seasonal allergies.

Meteorologist Cheryl Nelson presenting to a group in a green dress

Meteorologist Cheryl Nelson

Meteorologist Cheryl Nelson told us all about allergy season, the different kinds of allergies, what causes seasonal allergies, how long they last, and most importantly, how to treat them (including what a HEPA filter can do).

What are the symptoms of seasonal allergies?

About 50 million people in the U.S. have a nasal allergy. That’s a lot of sneezing!

Symptoms of seasonal allergies can include sneezing, coughing, a runny nose, itchy eyes, and stuffy ears.

Woman sneezing into tissue

Common allergens

This graphic shows the top 10 most common allergens (you can click on it to go to a bigger version). Some of them are just too gross to think about.

Graphic showing the top 10 allergens

Pollen allergies

When is allergy season?

There are three main allergy seasons: trees cause trouble in spring, grass in the summer, and weeds in the fall. So basically, winter is the only escape from seasonal allergies in much of the country.

Tree pollen allergy season

A bunch of trees

Birch, ash, elm, oak, and maple are just some of the trees that can cause allergic reactions.

Ironically though, many cities have made the problem worse. Female trees have more seed litter, so in order to keep the mess in check, many places planted only male trees. What those places failed to take into account was that male trees have way more pollen than female trees!

Tree allergies are usually the worst in spring.

Grass allergy season

close-up of grass

Grass allergies are worst in the summer. Ryegrass and bermudagrass are two of the worst grasses for allergies, so if you have grass allergies, try to avoid planting those. 

You can also help grass allergies by keeping grass cut short. 

Ragweed allergy season

While many varieties of weeds can cause allergies, ragweed is the absolute worst. Fall is when ragweed is most active.

Flower pollen allergy

You’ll notice that flowers weren’t mentioned in that list of seasonal pollen allergies. Flowers get a bad rap, but they actually don’t cause anywhere near as many seasonal allergies as trees, grass, and weeds. Flower pollen is relatively heavy, so it just can’t travel as far. That’s why flowers rely on bees to pollinate them (the pollen sticks to the bees’ hair, and then rubs off on other flowers).

If you’re allergic to flower pollen, then flowers will likely bother you when you’re near flowers, but their pollen won’t follow you around on the wind, so they don’t really have a season.

Stacy Neylan teaching how to arrange flowers

Stacy Neylan of Winston Flowers

As part of this event, we got a lesson in flower arranging from Winston Flowers, which was a lot of fun. I’ll have more about that next week.

How far does tree pollen travel?

Lighter pollen, though, can travel hundreds of miles on the wind. In fact, cedar pollen from Oklahoma was found in Ontario a day and a half later, over 1,000 miles away!

Most trees are pollinated by the wind, so their pollen has to be light in order for the trees to reproduce and survive. The exception is fruit trees, which are pollinated by animals, including bees.

Grass is also pollinated by wind.

How do mold spores travel?

While not pollen, mold spores can also float through the air and cause allergic reactions. Mold allergies are the worst in late summer and early fall. 

Does rain help allergies?

If you suffer from seasonal allergies, rain can be your friend, since it washes away the pollen. What it doesn’t wash away gets weighed down and can’t float on the wind. That’s why there are more pollen and mold spores floating around in hot, dry weather.

Pollen and climate change

Unfortunately, climate change is making pollen worse. More warm days mean more things growing for a longer amount of time, which means more pollen.

Indoor allergens

In addition to mold, which can grow indoors as well as out, there are other irritants that can cause nasal allergies. And while not seasonal in nature, their treatment is often similar.

Cigarette smoke can contribute to allergies. So can the volatile organic compounds (VOCs) in household items like laundry soap, paint, and nail polish remover.

Dogs and cats are big causes of allergies. Of course, if you live with a pet that you’re allergic to, that’s probably by choice. I have a cat that I’m allergic to. Here’s KitKat, helping me work:

My cat next to my laptop 

Dust mites are a big contributor to nasal allergies: 20 million people in the U.S. are allergic to them. Technically, they’re allergic to dust mite poop. Gross.

And honestly I don’t even want to talk about cockroach and rodent poop allergens, but just know that they’re a thing.

How outdoor allergens get inside

What helps seasonal allergies the most when you’re inside is to keep the allergy-causing particles outside. Outdoor allergens can come inside through open windows, on pets, and on people. Pollen and mold spores can even stick to carpet and drapes. Keeping windows closed when there’s pollen in the air can help a lot. Air conditioning units with filters also help.

How to relieve allergy symptoms

So now that I’ve outlined many of the things that can give you a nasal allergy reaction, what can you do about it? A lot, actually (although you have more control when you’re indoors).

When you’re outside

Wear sunglasses outside to help keep pollen from floating into your eyes. If your eyes start to itch, don’t touch or rub them, since that can just rub the pollen deeper into your eyes.

When you’re inside

Since you can control your indoor environment better than the outdoors, there are more things you can do when you’re inside to help relieve allergy symptoms or even prevent them from happening at all.

What is a HEPA filter?

A display of Honeywell air purifiers

HEPA stands for High Efficiency Particulate Air, and in order to be called a HEPA filter, a unit has to be able to remove 99.97% of particles that are 0.3 microns or bigger. For comparison, the diameter of a human hair is about 50 microns.

That’s more than enough to take almost all allergens out of the air. A HEPA filter can catch mold spores (3 microns and up), pollen (10 microns and up), and dust mite poop (10 microns and up). 

How a HEPA filter works

Basically, Honeywell air purifiers force air through two filters. The first is an activated carbon filter that catches the big particles, plus odors. Next, the air goes through a very fine mesh, trapping pollen, dust, mold spores, and other allergens, with cleaned air coming out of the other side.

A Honeywell air purifier can circulate all of the air in a room up to five times every hour while it’s running (in the appropriate size room, of course—know the square footage of your room before you shop for an air purifier). 

Do air purifiers kill mold spores?

Yes, but indirectly. Mold needs moisture in order to live and grow, and once the mold spores get trapped in the pre-filter or filter, the air rushing past takes away their moist growing environment, and the spores die.


So there you have it, everything I know about allergies and how to help relieve their symptoms (or even prevent them!). I’ll be trying out a Honeywell air purifier soon in my office. Thanks to guinea pigs, cigarette smoke from the sidewalk below, and the dust of a very old house, it should get quite a workout. I’ll report back.

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