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Asthma Triggers

Outdoor Air Pollution

Pollution caused by industrial emissions and automobile exhaust can cause an asthma episode. In large cities, and other areas that have air pollution problems, the number of emergency department visits for asthma episodes goes up when the air quality is very poor.

Tobacco Smoke (including secondhand smoke)

Smoking around children can cause more severe asthma and other serious health problems. Parents, friends and relatives of children with asthma should try to stop smoking. Until smokers can successfully quit, they should smoke only outdoors, not in the home or in the family car. Parents of children with asthma should make sure the child's school is smoke free.  

Dust Mites

Mattress covers and pillow case covers provide a barrier between house dust mites and the person with asthma. Down-filled pillows, quilts or comforters should not be used and stuffed animals and clutter should be removed from bedrooms.

Cockroach Allergen

Cockroaches can be found in any place where food is eaten and crumbs are left behind. Decreasing exposure to cockroaches in the home can help reduce asthma attacks. Remove as many water and food sources as possible because cockroaches need food and water to survive. Vacuum or sweep these areas at least every two-to-three days. Roach traps or gels can be used to decrease the number of cockroaches in the home.


Pets with fur or dander may trigger an attack. The simplest solution to this situation is to find another home for the pet. However, some pet owners may be too attached to their pets or unable to locate a safe new home for the animal. Any animal causing an allergic reaction should not be allowed in the bedroom. Pets should be kept outside as much as possible and kept clean. Frequent vacuuming will reduce the presence of the allergen. If the room has a hard surface floor, damp mop it weekly.


When mold is inhaled, it can cause asthma attacks. Eliminating mold throughout the home can help control asthma attacks. Keep humidity levels between 35 and 50 percent. In hot, humid climates, this may require the use of air conditioning and/or dehumidifiers. Fixing water leaks and cleaning up any mold in the home can also help.

Other Triggers

  • strenuous physical exercise;
  • weather conditions like freezing temperatures, high humidity and thunderstorms;
  • some foods and food additives;
  • some drugs; and
  • strong emotions (such as crying or laughing).

People with asthma should become aware of what triggers their episodes and avoid those triggers when possible.