An allergen is something that causes allergy signs, or an allergic reaction. Many of the same asthma triggers also cause allergic reactions in people who don't have asthma. There are many common allergens. Some are those listed here. It's very important to talk to your doctor if you have had a reaction to any of these:

Household triggers: pets (most often animal skin flakes or "dander"), smoke, mold, dust and dust mites.

Foods: milk and dairy products, citrus fruit like oranges and lemons, artificial colors and favors, nuts, and shellfsh, like shrimp or clams.

Medicines: penicillin, some heart medicines, and some anti-seizure medicines.

Insect stings and bites: most are caused by yellow jackets, honeybees, paper wasps, hornets and fire ants. In some people, reactions to stings become more serious as years go by. Eventually, it may take only one sting to kill. Talk to your doctor if you have had a serious reaction to a sting. Bed Bugs are a growing problem in homes too. Visit EPA's Bed Bug resource page to learn how to deal with these pests!

Contact allergens: cause reactions when things like plants, cosmetics, jewelry, or latex (a type of rubber) touch the skin. Rashes are common reactions to these allergens.

What can you do?

• Know your allergies, and know what to avoid. Not everyone is allergic to the same things!
• Contact your doctor about any unusual reactions to food, plants, medicines, or other items.
• Avoid contact with things you know trigger allergies. Avoid being outside or having the windows open when pollen counts are high. Read food labels carefully to avoid ingredients that cause reactions. Choose medicines and home-care products carefully. Remove carpet or vacuum often to avoid animal dander.
• Keep a clean home. Control pests such as mice and cockroaches. Vacuum floors and upholstery often and consider removing carpet. Avoid having mold, cigarette smoke, pesticides, and chemicals inside the house. Keep pets out of the bedrooms of family members who are allergic to them.

In the event of a severe allergic reaction, seek emergency medical attention immediately.

If you have asthma, an asthma attack can happen when you are exposed to “asthma triggers.” Your triggers can be very different from those of someone else with asthma. Know your triggers and learn how to avoid them. Watch out for an attack when you can’t avoid the triggers. Some of the most common triggers are:

Tobacco Smoke

Tobacco smoke is unhealthy for everyone, especially people with asthma. If you have asthma and you smoke, quit smoking.

“Secondhand smoke” is smoke created by a smoker and breathed in by a second person. Secondhand smoke can trigger an asthma attack. Make your home a smoke-free zone. Encourage household members who smoke to quit. If you have asthma, people should never smoke near you, in your home, in your car, or wherever you may spend a lot of time.

Dust Mites

Dust mites are microscopic bugs that are in many homes. If you have asthma and are allergic to dust mites, they can trigger an asthma attack. To prevent attacks:

• Use allergen-proof mattress and pillowcase covers to make a barrier between dust mites and yourself.
• Don’t use down-filled pillows, quilts, or comforters.
• Wash your bedding weekly and dry it completely.
• Vacuum carpets, area rugs, and floors regularly using a vacuum equipped with a HEPA filter.
• Keep relative humidity levels in the home low, around 30- 50%.

Outdoor Air Pollution

Outdoor air pollution can trigger an asthma attack. This pollution can come from many sources, including factories, cars, or wildfire smoke. Wildfire smoke from burning wood or other plants is made up of a mix of harmful gases and small particles. Breathing in too much of this smoke can cause an asthma attack.

Pay attention to air quality forecasts on radio, television, and the internet and check your newspaper to plan your activities for when air pollution levels will be low.

Pests (e.g., cockroaches, mice)

Cockroaches and other pests are often found where food is eaten and crumbs are left behind. To control pests in your home:

• Remove as many water and food sources as you can.
• Clean dishes, crumbs, and spills right away.
• Store food in airtight containers.
• Keep trash in a closed container.
• At least every 2 to 3 days, vacuum or sweep areas that might attract cockroaches or mice.
• Keep counters, sinks, tables, and floors clean and free of clutter.
• Seal cracks or openings in cabinets, walls, baseboards, and around plumbing.
• Use pesticide baits and traps in areas away from children and pets, following manufacturers’ instructions.
• Avoid using sprays and foggers as these can cause asthma attacks.

Pets

Furry pets can trigger an asthma attack if you are allergic to them. If you think a furry pet may be causing attacks, you may want to find the pet another home. If you can’t or don’t want to find a new home for the pet, decrease your exposure by:

• Keeping pets out of bedrooms,
• Washing furry pets,
• Using an air cleaner with HEPA filter, and
• Using allergen-proof mattress and pillow covers.

People with asthma are not allergic to their pet’s fur, so trimming a pet’s fur will not help your asthma.

Mold

Breathing in mold can trigger an asthma attack whether or not you are allergic to mold. Indoor mold growth is often found in damp areas such as kitchens, bathrooms, and basements, or in areas where water damage has occurred. There are many types of mold which can be found in any climate. Get rid of mold in your home to help control your attacks.

To reduce mold exposure in your home:

• Dry damp or wet items within 24 to 48 hours to prevent mold growth.
• Fix water leaks, such as leaky plumbing, which let mold grow behind walls and under floors as soon as you can.
• Replace absorbent materials, such as ceiling tiles and carpet, if mold is present.
• Use an air conditioner or dehumidifier to maintain low indoor humidity.
• Get a small tool called a hygrometer to check humidity levels and keep them as low as you can—no higher than 50%. Humidity levels change over the course of a day, so check the humidity levels more than once a day.
• Scrub mold off hard surfaces with detergent and water. Dry completely.
• Empty and clean refrigerator and air conditioner drip pans regularly.
• Run the bathroom exhaust fan or open the window when showering.

Cleaning and Disinfection

Disinfectants can trigger an asthma attack. People with asthma should try to stay away when cleaners or disinfectants are being used and right after their use. Follow these precautions when cleaning or disinfecting places where people with asthma may spend time, such as homes, schools, or workplaces:

• Avoid overuse of products. To help limit your exposure to asthma triggers, follow a schedule for cleaning and disinfecting to prevent overuse of products.
• Use safer products. Any disinfectant can trigger an asthma attack, but you can take steps to reduce the chances of that happening:
  • Use soap and water or cleaners certified by the EPA Safer Choice program to clean surfaces.
  • Clean visibly dirty surfaces before disinfecting.
  • Never mix disinfectant products.
  • Choose products for disinfecting that are less likely to cause an asthma attack, such as products with hydrogen peroxide (no stronger than 3%) or ethanol (ethyl alcohol). Ensure that products with hydrogen peroxide or ethanol do not contain other chemicals that can cause an asthma attack such as peroxyacetic acid or peracetic acid.
  • Avoid using bleach (sodium hypochlorite) or quaternary ammonium compounds in enclosed spaces and limit their use.
  • Avoid products with fragrances. The fragrances can trigger asthma attacks.
• Make sure there is enough air flow (ventilation).
  • Open doors and windows to bring in fresh air, if it’s safe to do so.
  • Improve ventilation by turning on exhaust fans. Exhausting the air (blowing it outside) is the most effective way to remove disinfectant vapors.
  • For buildings with heating or cooling systems that have fresh (outdoor) air intakes, turn on the fresh air intake to bring in fresh air.
  • • Using a high efficiency filter (MERV 13 or higher) with your heating and cooling system can help keep air clean by removing particles such as smoke, pollen, and traffic pollution from the air. Most air filters will not remove disinfectant vapors, though.
    • Make sure to follow the manufacturer’s instructions and to replace the filter as needed. Some systems cannot accept high efficiency filters. In this case, using the highest MERV rating possible will provide the most effective air cleaning.
• Use products safely and correctly.
  • Always follow the instructions on the product label. Do not mix chemical products together.
  • Wear protective gear such as gloves and goggles.
  • Spray or pour spray products onto a cleaning cloth or paper towel instead of spraying the product directly onto the cleaning surface (if the product label allows) to help limit exposure.
• Avoid disturbing dust because it can be an asthma trigger.
• Move away from the trigger (such as the area that was cleaned) if you experience an asthma attack, and follow your Asthma Action Plan. Call 911 for medical emergencies.

Other Triggers

Infections linked to influenza (flu), colds, and respiratory syncytial virus (RSV) can trigger an asthma attack. Sinus infections, allergies, pollen, breathing in some chemicals, and acid reflux can also trigger attacks.

Physical exercise; some medicines; bad weather, such as thunderstorms or high humidity; breathing in cold, dry air; and some foods, food additives, and fragrances can also trigger an asthma attack.

Strong emotions can lead to very fast breathing, called hyperventilation, that can also cause an asthma attack.

Molds create tiny spores to reproduce, just as plants produce seeds. Mold spores float through the indoor and outdoor air continually. When mold spores land on damp places indoors, they may begin growing. Molds are microscopic fungi that live on plant and animal matter. Molds can be found almost anywhere when moisture is present.

For people sensitive to molds, inhaling mold spores can trigger an asthma attack.

Actions You Can Take

• If mold is a problem in your home, you need to clean up the mold and eliminate sources of moisture.
• If you see mold on hard surfaces, clean it up with soap and water. Let the area dry completely.
• Use exhaust fans or open a window in the bathroom and kitchen when showering, cooking or washing dishes.
• Fix water leaks as soon as possible to keep mold from growing.
• Dry damp or wet things completely within one to two days to keep mold from growing.
• Maintain low indoor humidity, ideally between 30-50% relative humidity. Humidity levels can be measured by hygrometers, which are available at local hardware stores.

Secondhand smoke is the smoke from a cigarette, cigar or pipe, and the smoke exhaled by a smoker. Secondhand smoke contains more than 4,000 substances, including several compounds that cause cancer.

Secondhand smoke can trigger asthma episodes and increase the severity of attacks. Secondhand smoke is also a risk factor for new cases of asthma in preschool-aged children. Children's developing bodies make them more susceptible to the effects of secondhand smoke and, due to their small size, they breathe more rapidly than adults, thereby taking in more secondhand smoke. Children receiving high doses of secondhand smoke, such as those with smoking parents, run the greatest relative risk of experiencing damaging health effects.

Actions You Can Take

• Don't let anyone smoke near your child.
• If you smoke — until you can quit, don't smoke in your home or car.

Dust mites are tiny bugs that are too small to see. Every home has dust mites. They feed on human skin flakes and are found in mattresses, pillows, carpets, upholstered furniture, bedcovers, clothes, stuffed toys and fabric and fabric-covered items.

Body parts and droppings from dust mites can trigger asthma in individuals with allergies to dust mites. Exposure to dust mites can cause asthma in children who have not previously exhibited asthma symptoms.

Actions you can take

• Common house dust may also contain asthma triggers. These simple steps can help: Wash bedding in hot water once a week. Dry completely.
• Use dust proof covers on pillows and mattresses.
• Vacuum carpets and furniture every week.
• Choose stuffed toys that you can wash. Wash stuffed toys in hot water. Dry completely before your child plays with the toy.
• Dust often with a damp cloth.
• Use a vacuum with a HEPA filter on carpet and fabric-covered furniture to reduce dust build-up. People with asthma or allergies should leave the area being vacuumed.

Droppings or body parts of cockroaches and other pests can trigger asthma. Certain proteins are found in cockroach feces and saliva and can cause allergic reactions or trigger asthma symptoms in some individuals.

Cockroaches are commonly found in crowded cities and the southern regions of the United States. Cockroach allergens likely play a significant role in asthma in many urban areas.

Actions You Can Take

• Insecticides and pesticides are not only toxic to pests — they can harm people too. Try to use pest management methods that pose less of a risk.
• Keep counters, sinks, tables and floors clean and free of clutter.
• Clean dishes, crumbs and spills right away.
• Store food in airtight containers.
• Seal cracks or openings around or inside cabinets.

Proteins in your pet's skin flakes, urine, feces, saliva and hair can trigger asthma. Dogs, cats, rodents (including hamsters and guinea pigs) and other warm-blooded mammals can trigger asthma in individuals with an allergy to animal dander.

The most effective method to control animal allergens in the home is to not allow animals in the home. If you remove an animal from the home, it is important to thoroughly clean the floors, walls, carpets and upholstered furniture.

Some individuals may find isolation measures to be sufficiently effective. Isolation measures that have been suggested include keeping pets out of the sleeping areas, keeping pets away from upholstered furniture, carpets and stuffed toys, keeping the pet outdoors as much as possible and isolating sensitive individuals from the pet as much as possible.

Actions You Can Take

• Find another home for your cat or dog.
• Keep pets outside if possible.
• If you have to have a pet inside, keep it out of the bedroom of the person with asthma.
• Keep pets off of your furniture.
• Vacuum carpets and furniture when the person with asthma is not around.

What is pollen?

Pollen is the grains or tiny seeds of flowering plants, trees, and grasses. These seeds can be carried on the wind and can cause various symptoms, or none at all, in individuals who are exposed to them.

What health problems can pollen cause?

For people with hay fever, also known as “allergic rhinitis,” breathing in pollen can cause sneezing, congestion, and a runny nose. Pollen exposure can also result in “allergic conjunctivitis” in some individuals, causing red, watery, or itchy eyes.

Pollen exposure can also cause asthma attacks in people who have asthma and for whom pollen is an asthma trigger.

How can I protect myself against pollen?

If you are allergic to pollen, or if you have asthma you can take steps to protect yourself:

• Check pollen forecasts on local news and online sources and plan to spend less time outdoors when pollen levels will be high.
• Take your allergy and/or asthma medications as prescribed by your health care provider.
• Don’t touch your eyes while you are outside, and wash your hands when you go back inside (before you touch your eyes).
• Shower after being outside to remove pollen from your skin and hair.
• Change your clothes after being outdoors.
• Keep windows closed during pollen season.
• Use high-efficiency filters in your home’s heating, ventilation, and air conditioning (HVAC) system. Make sure your HVAC system can use high-efficiency filters and that they don’t violate the system’s warranty.

How is climate change affecting pollen levels?

Our changing climate has caused shifts in precipitation patterns, more frost-free days, warmer seasonal air temperatures, and more carbon dioxide (CO₂) in the atmosphere. These changes can affect:

• when the pollen season starts and ends and how long it lasts each year,
• how much pollen plants create and how much is in the air, and
• how pollen affects human health.

Some of these changes in pollen due to climate change could have major impacts on human health such as increasing individuals’ exposure to pollen and their risk of having allergy and/or asthma symptoms.

Nitrogen dioxide (NO2) is an odorless gas that can irritate your eyes, nose and throat and cause shortness of breath. NO2 can come from appliances inside your home that burn fuels such as gas, kerosene and wood. NO2 forms quickly from emissions from cars, trucks and buses, power plants and off-road equipment. Smoke from your stove or fireplace can trigger asthma.

In people with asthma, exposure to low levels of NO2 may cause increased bronchial reactivity and make young children more susceptible to respiratory infections. Long-term exposure to high levels of NO2 can lead to chronic bronchitis. Studies show a connection between breathing elevated short-term NO2concentrations, and increased visits to emergency departments and hospital admissions for respiratory issues, especially asthma.

Actions You Can Take

If possible, use fuel-burning appliances that are vented to the outside. Always follow the manufacturer's instructions on how to use these appliances.

• Gas cooking stoves: If you have an exhaust fan in the kitchen, use it when you cook. Never use the stove to keep you warm or heat your house.
• Unvented kerosene or gas space heaters: Use the proper fuel and keep the heater adjusted the right way. Open a window slightly or use an exhaust fan when you are using the heater.

Outdoor air pollution is caused by small particles and ground level ozone that comes from car exhaust, smoke, road dust and factory emissions. Outdoor air quality is also affected by pollen from plants, crops and weeds. Particle pollution can be high any time of year and are higher near busy roads and where people burn wood.

When inhaled, outdoor pollutants and pollen can aggravate the lungs, and can lead to:

• Chest pain
• Coughing
• Digestive problems
• Dizziness
• Fever
• Lethargy
• Sneezing
• Shortness of breath
• Throat irritation
• Watery eyes

Outdoor air pollution and pollen may also worsen chronic respiratory diseases, such as asthma.

Actions You Can Take

Get more information about Ozone Maps, Air Quality Forecasts, Ozone Action Days and more.

• Monitor the Air Quality Index on your local weather report.
• Know when and where air pollution may be bad.
• Regular exercise is healthy. Check your local air quality to know when to play and when to take it a little easier.
• Schedule outdoor activities at times when the air quality is better. In the summer, this may be in the morning.
• Stay inside with the windows closed on high pollen days and when pollutants are high.
• Use your air conditioner to help filter the air coming into the home. Central air systems are the best.
• Remove indoor plants if they irritate or produce symptoms for you or your family.
• Pay attention to asthma warning signs. If you start to see signs, limit outdoor activity. Be sure to talk about this with your child's doctor.

Chemical irritants are found in some products in your house and may trigger asthma. Your asthma or your child's asthma may be worse around products such as cleaners, paints, adhesives, pesticides, cosmetics or air fresheners. Chemical irritants are also present in schools and can be found in commonly used cleaning supplies and educational kits.

Chemical irritants may exacerbate asthma. At sufficient concentrations in the air, many products can trigger a reaction.

Actions You Can Take

If you find that your asthma or your child's asthma gets worse when you use a certain product, consider trying different products. If you must use a product, then you should:

• Make sure your child is not around.
• Open windows or doors, or use an exhaust fan.
• Always follow the instructions on the product label.

Smoke from wood-burning stoves and fireplaces contain a mixture of harmful gases and small particles. Breathing these small particles can cause asthma attacks and severe bronchitis, aggravate heart and lung disease and may increase the likelihood of respiratory illnesses. If you're using a wood stove or fireplace and smell smoke in your home, it probably isn't working as it should.

Actions You Can Take

• To help reduce smoke, make sure to burn dry wood that has been split, stacked, covered and stored for at least 6 months.
• Have your stove and chimney inspected every year by a certified professional to make sure there are no gaps, cracks, unwanted drafts or to remove dangerous creosote
  build-up.
• If possible, replace your old wood stove with a new, cleaner heating appliance. Newer wood stoves are at least 50% more efficient and pollute 70% less than older models.
  This can help make your home healthier and safer and help cut fuel costs.

Although many people report being adversely affected by fragrances, the issue remains controversial.

While some individuals may dislike a particular fragrance and may experience physical reactions from exposure to them, others exposed to the same fragrance may appreciate the smell or attribute health benefits to the exposure (e.g., aromatherapy).

There is also controversy among scientists as to whether the odor causing ingredients of some fragranced products actually ‘cause’ the adverse physical impact (e.g., triggering asthma episodes) experienced by some individuals or whether the adverse impact is caused by physiological, physical, chemical or emotional factors not directly related to the odor.

In spite of the controversy, EPA’s Indoor Environments Division (IED) understands that exposure to fragrances can cause some sensitive individuals to experience asthma episodes and other adverse health impacts and therefore notes this potential in several of their indoor air quality publications.

In addition, IED continues to monitor the research and works with our federal, state and local partners to provide up-to-date science-based information to the public on this and other indoor air quality issues.

If someone in your family has allergies or asthma, make your home a healthier place by getting rid of the things that can cause allergy symptoms or an asthma attack.

What can cause allergy symptoms or an asthma attack?

Things that can cause allergy symptoms are called allergens. Asthma attacks can be caused by irritants (things that can irritate the lungs) or allergens. Different people will react to different allergens and irritants.

Common causes of allergy symptoms and asthma attacks at home include:

• Mold or dampness
• Dust mites (tiny bugs that live in beds and carpets)
• Pets with fur, including cats and dogs
• Cockroaches (roaches and their droppings may cause asthma)
• Mice, rats, and other rodents
• Secondhand smoke
• Wood smoke
• Strong fragrances

Take Action!

Follow these steps to make your home a healthier place for people with allergies or asthma.

Find out what causes your allergy symptoms or asthma attacks.

If you or someone in your family has asthma, it’s important to figure out what can trigger (cause) an asthma attack. Asthma triggers can be different for different people.

Ask your doctor about getting an allergy test. This test can help you know what exactly is causing your allergies.

When you know what you are allergic to – or what your asthma triggers are – you can take steps to get rid of or avoid those things in your home.

Keep allergens and irritants out of the bedroom.

• Cover your mattresses and pillows in “dust proof” (or "allergen proof") covers.
• Wash all your bedding in very hot water (at least 130 °F) once a week. Go to a laundromat if the water in your home doesn't get that hot.
• Keep stuffed animals off the bed.
• If you have pets that you are allergic to (like cats or dogs), keep them out of the bedroom.
• If possible, remove all carpets. It’s easier to keep bare floors clean.

Control moisture to prevent mold.

Keep your home dry to prevent mold. Mold can start to grow in wet or damp places within just 1 or 2 days.

• If you have a water leak, clean up the water right away. Fix the leak as soon as possible.
• When you take a shower, run the bathroom fan or open the window for at least 20 minutes afterward.
• Check the humidity level in your home with a moisture or humidity meter (available at a hardware store).
• Use a de-humidifier or air conditioner to keep the humidity level in your home below 60 percent. A humidity level between 30 and 50 percent is best.

If you rent your home and there's mold in it, you may be able to ask your landlord or property manager to clean up the mold. Check with your local county or state health department to learn more about your rights.

What if the air in my home is too dry?

While moist (wet) air can lead to mold, dry air can be uncomfortable.

If the air in your home is dry in the winter, you can use a humidifier. Just be sure to still keep the humidity level between 30 and 50 percent.

Keep pests out of your home.

Rodents (mice and rats) and cockroaches can trigger allergy or asthma attacks if you are allergic to them. Take these steps to help prevent pests:

• Fix leaks in sinks and toilets.
• Put trays under your plants, radiators, and refrigerator. Check the trays for water and clean them often.
• Store food (including pet food) in closed containers.
• Clean up crumbs and spills right away.
• Fill in cracks or holes that could be good indoor hiding places for pests.
• Put screens in your windows and doors.
• If you see roaches or rodents, call a pest control company.

Make a no-smoking rule in your home.

Cigarette smoke, including secondhand smoke, can make asthma worse. And babies who live in homes where people smoke are at higher risk of developing asthma.

If you have guests who smoke, ask them to smoke outside. If you smoke, make a plan to quit today.

Avoid burning wood inside your home.

Breathing too much smoke from a wood-burning stove or fireplace can cause an asthma attack. If you can avoid it, don’t burn wood in your home.