Anything that irritates your airways and causes your asthma symptoms to flare-up, is a trigger. What triggers someone’s asthma symptoms may be different from someone else’ experience. It is important to identify the triggers that provoke your asthma symptoms so you can learn strategies to control them.

A. Triggers that can provoke asthma symptoms and flare-ups:

  • Tobacco and secondhand smoke:  To reduce exposure to tobacco smoke (cigarette, pipe, vaping), make your home smoke-free, keep your car smoke-free and, encourage household members to smoke outside until they stop smoking.
  • Outdoor Air Pollution:  Air pollution affects everyone. People with asthma are among those who are at greatest risk of harm from breathing outdoor pollutants (e.g., gas and diesel emissions, wood smoke, fires).  Stay informed about the air quality by accessing the Air Quality Index, AirNow or your local weather report. Schedule outdoor activities at times when the air quality is satisfactory.
  • Indoor Nitrogen Dioxide (NO2):  As an odorless gas released from using appliances that burn gas, wood, and kerosene, NOcan have harmful effects on the respiratory system. Exposure to high levels of NO2 can contribute to the development of asthma, increase one’s susceptibility to respiratory infections, and worsen asthma symptoms.  To reduce the exposure to NO2, exhaust fans installed over gas stoves and vented outdoors must be operational. A gas stove should never be used to warm up living areas.  When operating gas heaters, proper instructions include proper fuel use, adjusted settings, and ventilation (open windows). 
  • Chemical products used for cleaning, disinfection, air fresheners and aerosol sprays release volatile organic compounds (VOC) that are harmful to the respiratory system and general health. Other harmful products include ammonia and bleach.  Exposure to cleaning and disinfectant chemicals (including bleach) at home, school or workplaces can trigger asthma symptoms. Using alternative cleaning solutions are safest.  To find safer choice-certified products, click hereLow-cost cleaning alternatives include the use of warm water and soap, baking soda and vinegar. It is recommended to open windows and doors when using cleaning household products.
  • Respiratory infections are common causes of asthma symptoms and flare-ups. To reduce the risk of exposure to colds and the flu, handwashing and getting annual influenza vaccine are recommended.
  • Other asthma triggers include acid reflux, certain foods and medicines, physical activity, cold air, strong emotions.

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B.  Common Allergens that trigger asthma symptoms      

Dust mites are found in bedding, mattress, soft and stuffed toys, upholstered furniture, carpets.        

To decrease the exposure to dust mites:

  • Dust proof pillows and cover mattresses
  • Vacuum with a HEPA filter weekly on carpets and furniture
  • Use a damp cloth to dust
  • Choose stuffed toys that can be washed in hot water   

Mold spores float and land on moist places indoors and outdoors.

To remediate:

  • Clean mold with soapy water
  • Identify and repair sources of moisture: plumbing in bathroom and kitchen, windows, overwatered plants
  • Use fans in kitchen and bathrooms; Keep humidity between 30-50% (use hygrometers)
  • Use indoor dehumidifiers and air conditioners (during hot weather)           

Pests include cockroaches, rats, and mice. Cockroaches produce substances that can trigger both asthma and allergies. To reduce exposure to pests, it is key to eliminate their access to food and water.

  • Keep food in sealed containers and use a lid-covered trashcans.
  • Clean sinks, counters, stoves, floors. Avoid piling dirty dishes, newspapers, and laundry.
  • Fix any water leaks. Vacuum areas where food crumbs can be found.

Exposure to rodents’ droppings can cause allergies and cause asthma flare-ups.

  • Keep indoors areas clean and free of clutter
  • Keep food and trash in sealed containers
  • Repair holes, cracks in walls, windows, screens; seal with caulk, steel wool, copper mesh
  • If homeowner: Contact a Connecticut licensed professional pest control service
  • If tenant: Promptly notify (verbally and in writing) the landlord or property management

Integrated Pest Management

The Integrated Pest Management (IPM) is a safe approach to eliminate roaches, rodents, and other pests. The primary goal of IPM is to use alternative non-chemical methods of pest control, as a first line of defense. These methods help to eliminate conditions that are favorable to pest infestation, making their survival more difficult.  It includes removal of indoor and outdoor food sources (e.g., bird feeder), removal of access to water, elimination of places where rodents can hide/nest (e.g., leaf and debris around foundation) and the services by a Connecticut licensed professional pest control operator. 

Pest management resources for residents of multi-family housing:  Tips, Do’s, and Don’ts


Animal dander is found in pets’ skin flakes, saliva, hair, urine and feces Exposure to dogs, cats, hamsters, guinea pigs (warm blooded mammals) can trigger asthma flare-ups in people allergic to animal dander. While it is ideal for a pet to be removed out of household, it is possible to keep the animal and reduce the pet allergens.  

  • Vacuum and clean frequently floors, carpets, upholstered furniture
  • Isolate pets from the household member sensitive to dander by keeping pets away from sleeping areas, and furniture.       

Pollen grains are dispersed from flowering plants, trees, grass, and weeds and their amounts vary accordingly to the season and geographic region. Exposure to pollen can trigger allergic reactions such as rhinitis (known as hay fever), allergic conjunctivitis (itchy eyes), and for people with asthma, can cause asthma flare-ups.  Environmental factors to consider: hot and highly humid summers cause high pollen levels and extend the pollen periods, increase the growth of mold spores and dust mites and, account for poor air quality. 

  • Reducing exposure to pollen allergies include:
  • Eliminate pollen on clothes after being outside by changing them once indoors
  • Keeping windows closed or use a pollen and dust filter window screen
  • Use an HVAC or furnace high quality filter that traps mold spores, dust, and pollen.
  • Use an electrostatic filter for window air conditioner unit
  • Change car ail filter regularly

Allergy testing is part of the diagnostic processes that a healthcare provider may conduct if a person with asthma reports sensitization or asthma symptoms when exposed to specific allergens. 

Recommended resources

1. Controlling Air Pollutants in Multi-Unit Housing

2. Controlar los contaminantes del aire en viviendas multifamiliares