Indoor Environmental Asthma Triggers

Indoor Environmental Asthma Triggers and Asthma Action Plans

According to the U.S. Environmental Protection Agency (EPA) Americans spend up to 90% of their time indoors. Therefore, indoor allergens and irritants can play a significant role in triggering asthma attacks. It is important to recognize potential asthma triggers in the indoor environment and reduce your exposure to those triggers. You may not be affected by all of the triggers listed here. Your doctor can help you to determine which triggers affect your asthma and develop a specific plan to reduce your triggers.
Indoor Environmental Asthma Triggers

* Secondhand Smoke
* Dust Mites
* Molds
* Cockroaches and Pests
* Pets
* Nitrogen Dioxide
* Outdoor Air

You can download a sample Asthma Action Plan to help you work with your doctor to create an asthma action plan for your individual circumstances.

When you and your doctor make the plan, be sure to include:

* Your child’s asthma triggers.
* Instructions for asthma medicines.
* What to do if your child has an asthma attack.
* When to call your doctor.
* Emergency telephone numbers.

Some of the most common indoor asthma triggers include secondhand smoke, dust mites, mold, cockroaches and other pests, household pets, and combustion byproducts. Click on the links below to learn more about these triggers and how to reduce your exposure to them.
Secondhand Smoke

Secondhand smoke is a mixture of smoke from the burning end of a cigarette, pipe or cigar and the smoke exhaled by the smoker that is often found in homes and cars where smoking is allowed.

Dust Mites

Dust mites are too small to be seen, but can be found in almost every home in mattresses and bedding materials, carpets, upholstered furniture, stuffed toys and curtains.


Mold can grow indoors when mold spores land on wet or damp surfaces. In the home, mold is most commonly found in the bathroom, kitchen and basement.

Cockroaches and other Pests

Cockroach body parts, secretions and droppings, and the urine, droppings and saliva of pests, such as rodents, are often found in areas where food and water are present.

Warm-Blooded Pets (such as cats and dogs)

Pets’ skin flakes, urine and saliva can be found in homes where pets are allowed inside.

Nitrogen Dioxide

Nitrogen Dioxide is a reddish-brown, irritating odor gas that can be a byproduct of indoor fuel-burning appliances, such as gas stoves, gas or oil furnaces, fireplaces, wood stoves and unvented kerosene or gas space heaters.