Allergy sufferers may be tempted to stay indoors to avoid itchy eyes, scratchy throats and runny noses. But a new report from the United States Environmental Protection Agency reveals that indoor air can often be just as triggering as outdoor air. It seems no place is safe during allergy season.

But there are four items around the house that are especially likely to cause your allergies to flare.

Mattress

It may be hard to accept, but a recent survey revealed that almost all examined mattresses tested positive for at least one allergen, and and nearly 75% contained 3-6, according to the Journal of Allergy and Clinical Immunology.

Scientist say that many bedroom allergens can be caused by pets, pests, windows and dust. Our mattress and bedding tend to hold those allergens longer than other household items. Regularly washing your bedding in hot temperatures can help reduce the allergens.

The vacuum

A good vacuum cleaner can drastically reduce the allergens present in your home — a vacuum with a HEPA air filter can catch even the smallest of particles — but while they may make messes disappear, vacuums are literally filled with dust and allergens. Be sure to empty your vacuum’s bag or canister frequently, ideally outside of your house.

And remember: The best way to reduce allergens in the home is to keep them from getting in in the first place. Taking your shoes off before coming in the house helps keep allergens — and any other unhygienic particles — from coming in with you.

Window screens

Screens are fantastic for enjoying warm summer days and cool night breezes without letting bugs in the house. However, window screens can also act as magnets for pollen.

Take your screens out of the windows and scrub with water and soap. Cleaning your window screens every spring and fall will reduce the amount of pollen trying to find its way inside.

Furnace filters

When the spring weather starts to feel like a roller coaster — warm one minute and freezing the next — it’s common to feel sick. But in most cases your “sickness” might actually be allergies. And the culprit might well be your recently turned on air conditioner.

Before switching from heat to AC (or switching back in the fall), be sure to change the filters. Otherwise, you may be blowing months’ of trapped dust and pollen right into your home.

In fact, most experts recommend changing your filter at least every three months and even more frequently if you live in a high pollen area.