Americans spend up to 90 percent of their time indoors, and indoor allergens and irritants play a significant role in triggering asthma attacks. Triggers are things that can cause asthma symptoms, an episode or attack or make asthma worse. If you have asthma, you may react to just one trigger or you may find that several things act as triggers. Be sure to work with your OAAC provider to identify triggers and develop a treatment plan that includes ways to reduce exposures to your asthma triggers.