Indoor Air Quality at Home

Your home is your castle, be it a single-family dwelling, townhouse, apartment or mobile home. And whether you consider yourself a neat freak or a creatively cluttered person, the air inside your home could be making you sick.

Of course, homes are supposed to be a safe space. They are where we spend time with family, relax, eat meals, and sleep. But even if you think the air inside your home is clean, it may not be as healthy as you’d like. If we could see all the tiny air specks and chemicals we breathe each day, we’d be amazed at all the particles that bombard our airways.

Asthma and allergies are the most common health conditions linked with indoor air pollutants. Indoor allergens and irritants could cause an asthma attack. So it’s important to make sure you have good indoor air quality at home.

Family, with packing boxes around, are taking a moment to relax and play near an air purifier in their new home.

Indoor Air Pollutants in the Home

You may be wondering, what can cause poor indoor air quality in your home? Many people may think of air pollution as something that comes from the outside – such as pollen or exhaust fumes from cars. In reality, indoor air pollution is just as big of an issue. Think about it: when inside, there is no breeze to bring you fresh air. Instead, poor air is often recirculated.

In your home, you may be exposed to pollutants, allergens and irritants such as:

  • indoor mold

  • pet dander

  • accumulated house dust

  • dust mites

  • cockroaches, mice and rats

  • chemicals from household cleaning products

  • fumes from cooking on gas stoves

  • odors from scented products, air fresheners or perfume/cologne

  • tobacco smoke

  • outdoor air pollution (pollen, car exhaust) brought inside

Indoor air quality problems can build up over time and worsen the air we breathe. It is important to look for signs these allergens and irritants are present in your home. Some, like tobacco smoke, are obvious. Some, like mold behind a sink, are hidden. Like a detective, you’ll have to search for clues to indoor air quality problems.

Woman upset at mold she found behind her refrigerator after pulling it out.

Kitchen Clues

The kitchen is often a silent source of air pollution. A recent study found that nearly 13% of childhood asthma cases are linked to linked to gas stoves. Gas stoves can release nitrogen dioxide, carbon dioxide, and formaldehyde, which can irritate the lungs. Ideally, cooking with an electric stove is preferred. But switching to an electric stove may not be possible for some people.


Sink and Cabinets

  • Water puddles or leaks around or near the faucet or hardware

  • Loose or missing grout where the sink meets the countertop

  • Black or brown mold on the backsplash or countertop or around the drain

  • Dirty dishes

  • Scum or discoloration under the dish drain mat

  • Odors coming from the garbage disposal

  • Damp or wet plumbing pipes or flooring under sink

  • Musty or damp smell inside cabinet

  • Black, brown or rust-colored areas on back wall, pipes or flooring under sink

  • Gaps between pipes and wallboard

  • Warped or rotting wallboard or flooring

  • Black or brown rodent droppings (about the size of rice)

  • Dust clumps containing insect parts (cockroach nests)

  • Silverfish

  • Open or overflowing trash bin

  • Pet food, bird seed

  • Cleaning products, particularly those containing perfumes or other strong smell


  • Dust or slimy dark spots on top of or beneath the refrigerator 

  • Mold,dust and water in the drip pan (if you have one, the drip pan is usually beneath the refrigerator a few inches off the floor behind a kick plate)

  • Sticky substance left from liquid spills underneath the refrigerator

  • Dusty backside of the refrigerator and wall 

  • Black or brown rodent droppings (about the size of rice) on the floor

  • Moisture on refrigerator surfaces 

  • Black growth on the door or door seal (the flexible rubber gasket)


  • Dust, dust clumps containing cockroach eggs and decaying insects, decaying food and rodent droppings found on the floor or in the drawer 

  • Sticky, greasy filters on oven exhaust fan 

  • Roaches appear when oven is turned on

Waste Cans, Trash Compactor and Recycle Bins

  • Food clinging to waste can, compactor or recycle bin surfaces

  • Odors

  • Black or brown rodent droppings in or near waste can, compactor or recycle bin

Cupboards and Countertops

  • Green, gray, brown fuzzy growth on bread or yeast-containing products

  • Ashtrays

  • Cockroaches,silverfish

  • Black or brown rodent droppings on shelving or in drawers 

  • Paper grocery bags

Person's hand holding up a magnifying glass over a bathroom vanity checking for mold.

Bathroom Clues

Bathrooms are typically a damp part of our homes. The area inside and outside of our showers and bathtubs, as well as sinks, often get wet. This creates a health risk for mold. Showers and baths also produce steam. This can increase the humidity in the room, leading to mold and mildew.

Some other clues that you may have an indoor air problem in the bathroom:

  • Black or brown growth on grout or surfaces, particularly in corners. Check around the shower, tub enclosure, floor near shower, tub or sink, under sink or on backsplash, behind toilet tank or on floor at base of toilet)

  • Missing grout in bath, shower or sink areas 

  • Musty smell 

  • Dust or mold clinging to the exhaust fan vent cover

  • Fragranced or strong-smelling cleansers, personal hair and body care products.


Woman mopping the floor of a bedroom.

Bedroom Clues

In general, people spend most of their time each day indoors in the bedroom. Think about it: you spend at least 8-10 hours asleep in the bedroom each night. So your bedroom should be a safe place to sleep with good air quality. You want to be able to rest without breathing problems, especially if you have asthma.

Some clues that you may have an indoor air problem in the bedroom:

  • Humidity levels above 50 percent

  • Upholstered furniture or carpet in bedroom

  • Moldy smell from clothes hamper or dark spots on inside surfaces

  • Moisture or dark areas on window glass and/or window frame

  • White powdery coating on shoes in closet

  • Empty food containers, crumbs

  • Pets

  • Ashtrays

  • Hobby products

  • Stacked books and magazines

  • Deodorant sprays, room deodorizers, talc powders, perfumes, hairspray


Yellow couch with german shepherd on top. There are clothes thrown around the room.

Living Room Clues

Common allergens and irritants that may occur in the living room include dust mites, pet allergens, mold, secondhand smoke, firewood, coal dust and kerosene.

Clues that there may be an indoor air problem:

  • Ashtrays

  • Fabric upholstered furniture 

  • Pets 

  • Carpeting and padding 

  • Food crumbs on carpet and underneath couch cushions 

  • Stacked firewood or kindling, ashes or burned wood smell in the fireplace 

  • Kerosene heaters, wood stoves, coal stoves


Basement with cement and brick walls, filled with various storage of bottles, papers, and various junk items.

Basement Clues

Whether it’s finished or unfinished, allergens and irritants can accumulate in the basement. Common allergens include mold, cockroaches, pet dander and rodent droppings

Clues that there may be an indoor air problem:

  • Dampness 

  • Temperature and humidity differences from the rest of the house 

  • Musty smell; rodent or pet urine smell 

  • Silverfish, crickets, spiders or other insects 

  • Black or brown rodent droppings, particularly in corners or along the perimeter 

  • Mold spots or dust on coils of dehumidifier


Unfinished attic with various places mold can build up.

Attic Clues

Common allergens and irritants in the attic may include mold, insulation fibers, dust, bird and/or rodent droppings.

Clues that there may be an indoor air problem in the attic:

  • Sounds of birds or animals in the eaves 

  • Birds flying into eaves 

  • Bird or other animal droppings, carcasses 

  • Wet or warped interior walls, studs, flooring 

  • Daylight visible in areas that should not be exposed 

  • Moldy, damp or rotten smell 

  • Matted or moldy-looking insulation


Baskets of laundry on the laundry room floor, some with clothes in them, next to a washing machine.

Laundry Room Clues

Your laundry area may be down the hall of your apartment building, in your kitchen, outside your bedroom door, in the basement or in the garage. No matter where it is, always keep your laundry area clean and dry. This will help to eliminate mold, a sign of high air moisture content and possible hidden water damage.

Clues that there may be an indoor air problem in the laundry room:

  • High humidity or moisture levels 

  • Wet clothes left in the washing machine 

  • Wet clothing piles 

  • Clothing lint and dust on floor and walls near washer and dryer 

  • Cleaning agents such as bleach or heavily scented fabric cleaners and softeners


Messy garage with bikes, clothes, outdoor equipment, laundry area, etc.

Garage Clues

Home builders increasingly attach the car garage directly to the home – sometimes off the kitchen, underneath a bedroom or next to the family room. When used to store old paint cans, gasoline, lawn mowers, pesticides, wood stains, woodworking projects and/or household cleaners, the garage can become the most toxic room in the house. Chemicals seep into your breathing space through tiny cracks and gaps between the home’s foundation and walls. Families also often put trash cans and recycling bins and trash cans inside the garage. Failure to keep this area clean will attract rodents, cockroaches and other unwelcome allergens and irritants.

Clues that there may be an indoor air problem:

  • Attached garage

  • Car(s) frequently inside the garage 

  • Gasoline-powered tools and equipment 

  • Cleaners, pesticides and other strong-smelling chemicals 

  • Trash cans and recycle bins


Handyman cleaning vents

Improving Indoor Air Quality in Your Home

Start your search for allergens and irritants in the rooms where you know a problem exists or where breathing problems occur most often. If you or your child cough or sneeze a lot in the kitchen, start there. If there’s more coughing at night, start in the bedroom.

Tackle one room at a time. Spread out the cleaning over weeks or months. The kitchen, bathrooms and bedrooms are typically hot spots for air pollutants in the home. But it is important to check other areas, including the living room, dining room, basement and laundry room.

Generally speaking, here are some simple ways to go about protecting indoor air quality throughout your whole home:

  • Keep your home well ventilated by opening doors and windows when the outdoor air quality is good and pollen count is low. Keep ceiling fans on as well.

  • Use high efficiency particulate air (HEPA) filters on your HVAC system and have it serviced regularly. Make sure air ducts are clear and the air conditioning unit is running properly.

  • Keep the humidity level at 50% in your home. Too much humidity makes your home a playground for mold and dust mites. Too little can irritate inflamed airways. So meet in the middle at 50%.

  • Clean, clean, clean! Keeping your house clean is a big part of having healthy air in the home. Dust, vacuum and sweep regularly. Use a vacuum with a HEPA filter. Try cleaning one room a day or set aside a few hours to clean every week.

  • Replace carpets (if possible), upholstered furniture, heavy drapes and other allergen collectors with hardwood floors or washable furnishings. This will reduce dust mite exposure.

  • Wash curtains regularly or consider replacing them with blinds that can be dusted.

  • Don’t allow smoking in or around your house.

  • Clean the clothing dryer regularly. These can produce moisture as well. Be sure the outside vent keeps moisture from building up in your laundry area

  • Use nontoxic, fragrance-free cleaning products. Avoid using household cleaning products that contain harmful chemicals.

  • Check the house for leaks and mold.

Mother at the kitchen stove cooking, while two tween girls sit at the table looking in her direction.

Kitchen Air Quality

What can you do to improve poor indoor air quality in the kitchen?

Sink and Cabinets

  • Repair leaking faucets (a simple “o” ring or washer may do the trick) and pipes to discourage mold growth, rodents and other pests.
  • Wash dishes immediately after use; dry and replace in the cupboard.
  • Place thin lemon slices in the garbage disposal and turn it on while running cold water into the sink to keep it smelling fresh and clean.
  • Limit clutter under the sink; wipe the area clean monthly to discourage pests and mold growth.
  • Never store wet sponges or dish rags under the sink. l Stuff steel wool in gaps left around plumbing pipes to prevent rodents from entering the kitchen from behind the wall.
  • Use nontoxic, childproof insect and rodent traps or baits to reduce pests.
  • Use a lid on your trash bin. Empty trash daily. Clean the inside and outside of the trash bin weekly.
  • Store pet food and bird seed in airtight containers.
  • Wash and put away pet food dishes each night.
  • Replace odor-masking, fragranced and expensive cleaners with nontoxic, fragrance-free and inexpensive alternatives using ingredients you probably already have in your kitchen!


  • Keep the refrigerator top clutter-free to make dusting an easy part of your cleaning routine.
  • Sprinkle salt in the drip pan to inhibit mold growth.
  • Pull the refrigerator out from the wall. (You may want to wear a dust mask if it’s been a while since you did this!) Vacuum dust off refrigerator coils and fan; it will help reduce energy costs, too!
  • Damp mop the floor under the refrigerator each season.
  • Place nontoxic, childproof rodent bait or traps behind the refrigerator. Check them often!


  • Periodically remove and clean the drawer at the base of the oven and vacuum or mop the floor area underneath the oven.
  • Use nontoxic,childproof cockroach and/or rodent traps or bait.
  • Use an exhaust fan when cooking to reduce moisture and odors.
  • Clean exhaust fan filter or screen to remove cooking grease build-up.

Waste Cans, Compactor and Recycle Bins

  • Remove kitchen waste daily.
  • Do not use odor-masking products. Odor alerts you to an allergen or irritant, rotting food and/or moisture.
  • Keep waste can,compactor and recycle bin surfaces and areas clean.
  • Wash or rinse out bottles and cans before placing them in recycle bins.

Cupboards and Countertops

  • Discard bread and other bakery foods when no longer fresh.
  • Never allow anyone to smoke in your home.
  • Store all food in airtight containers or bags when not in use.
  • Keep countertops clean and free of crumbs or spills.
  • Place childproof, nontoxic cockroach and/or rodent baits in your kitchen. Follow package directions carefully.
  • Throw away stacks of old paper bags. (They’re perfect hiding places for cockroaches!)


person cleaning bathroom mold with spray, gloves, and sponge.

Bathroom Air Quality

What can you do to improve poor air quality in the bathroom?

  • Remove obvious signs of mold growth. Mold stains may be difficult or impossible to remove from white grout or caulking. While they can be unsightly, stains do not pose a health problem.

  • Replace missing grout. Repair or replace leaky faucets and pipes immediately. Your local home hardware expert can help do-it yourselfers or this may require plumbing skills.

  • Use an exhaust fan or open a window while showering to remove excess humidity. Wash exhaust fan vent covers to remove accumulated dust which may also contain mold.

  • Wipe the shower walls and tub toys dry after use.

  • Use a mold-proof shower curtain. Keep enclosure doors and tracking clean and free of mold build-up.

  • Dry your feet and legs before stepping onto the bathmat. Use a towel-style bathmat instead of a plush carpet. It is easier to clean and does not retain moisture as much as thicker or rubber-backed mats.

Woman's hand holding humidity therometer in a child's bedroom

Bedroom Air Quality

What can you do to have good indoor air quality in the bedroom?

  • Purchase an inexpensive humidity gauge to measure indoor air humidity. Keep humidity levels between 30 and 50 percent to minimize mold growth and dust mite populations.

  • Limit upholstered furniture, which becomes a breeding ground for dust mites. 

  • Choose washable stuffed toys; wash with bedding in hot water. Dry completely. Keep stuffed toys off the bed.

  • Use washable throw rugs and curtains (or use window shades or blinds instead).

  • Put pillows and mattress inside specially designed dust-mite-proof covers.

  • Wash bedding weekly in hot (130°F) water.

  • Vacuum and dust the bedroom once each week. Use a HEPA (high efficiency particulate air) filtered vacuum.

  • Vacuum mattress dust-mite covers when changing sheets or cleaning room.

  • Avoid carpeting in bedroom if possible. Existing carpet should be in good condition with no signs of mold or dust accumulation. Padding should be in good condition – no signs of crumbling or rotting. Simply walking across a carpeted floor sends tiny allergens into the air.

  • Empty clothes hamper daily. Never store wet items inside.

  • Do not allow clothing to pile on the floor or in corners.

  • Water droplets form on windows and window frames when air temperatures inside and outside the house vary greatly. There are numerous ways to fix the problem – some are very inexpensive. See your local home hardware experts for suggestions.

  • Find and stop the source of humidity in the closet causing powdery mold to form on shoes. Leave light on in closet.

  • Keep food out of the bedroom.

  • Use an air cleaner running at night when you’re asleep.

  • If allergic to pets, keep them out of the bedroom. (Pets usually adjust to this change faster than their owners!)

  • Avoid using the bedroom for hobby projects as these increase exposure to allergens, irritants and pollutants.

  • Limit bedroom reading material; stacked books and magazines retain humidity and encourage mold growth. 

  • Whenever possible, use unscented personal hygiene and hair care products. Do not use scented candles and odor-masking room deodorizers.

  • Keep potted plants (a source of mold growth) out of the bedroom.

  • Use paints or wallpaper treated with mold inhibitors when redecorating.


photo of Mother and her daugther having good time together using laptop at home on couch

Living Room Air Quality

What can you do to have good indoor air quality in the living room?

  • Never permit any person to smoke inside your home. 

  • Secondhand, upholstered furniture or antiques may contain mold, dust, dust mites and pet allergens. Replacement alternatives to consider include vinyl, leather or other washable-surface furniture. 

  • Keep pets off the furniture and out of the family room.

  • If family members are diagnosed with pet allergies, consider finding a new home for your pet or create safe and weather-protected living space outside the home for your animal. 

  • Vacuum underneath and behind furniture and underneath couch and chair cushions at least once a month. 

  • Vinyl beanbag chairs provide kid-friendly seating for watching television and playing games. 

  • Replace moldy carpet and padding. Check in front of doors leading to the outside of your home, in corners, etc., preferably with hardwood or other hard-surface flooring. Avoid products requiring toxic glues or fumes when possible. 

  • If the floor beneath the carpet is concrete, make certain the concrete was sealed or a moisture barrier or wood planking was placed between the padding and floor before the carpet was installed. If the basement has ever flooded, don’t install carpet or wood flooring. 

  • Use paints or wallpaper treated with mold inhibitors when redecorating. 

  • Eat meals in the kitchen/dining area. Enjoy snacking while watching television, but remember to clean under the couch, chairs, and cushions after eating. 

  • Use water-filled radiant electric heaters as a supplemental heat source in place of wood or coal stoves, fireplaces and kerosene space heaters.


Photo of woman looking at mold on a wall

Basement Air Quality

What can you do to have good air quality in the basement?

  • Look for the cause of dampness. Use a flashlight to look for cracks in the foundation or warped wallboard or paneling. Lift carpeting along the edges to check for mold growth. If interior walls are exposed, look for cracks in the foundation. If found, you may need to contact your landlord or an expert to repair the foundation of your home. 

  • If you plan to remodel an unfinished basement, contact your heating and air-conditioning contractor to ensure your existing system can handle the increased demand of heating and cooling finished spaces. 

  • Do not block air vents or restrict air flow around air handling equipment (furnace, swamp cooler, air conditioner, etc.). Keep the area clean and dry. 

  • Use a dehumidifier when humidity climbs over 50 percent.

  • Clean dehumidifier drip pan according to manufacturer’s instructions. 

  • Leave the lights on (mold prefers dark spaces) in basements with limited windows. 

  • Avoid using carpet on concrete basement floors. 

  • Ideally, apply a water sealant to outside walls before finishing basement interior. 

  • Replace cardboard storage boxes with plastic containers with lids. 

  • Wash mold off hard surfaces and dry completely. Moldy ceiling tiles, carpets, wood, furniture, etc., should be removed (wear a dust mask and goggles) and replaced. 

  • Be certain to fix the cause of the mold! 

  • Use childproof, nontoxic cockroach, insect or rodent bait or traps. 

  • Do not use the basement for sleeping purposes. Family members with asthma or allergies should minimize time spent in the basement.


Two workers in hard hats are looking at an air duct that needs repairing to keep the indoor air clean.

Attic Air Quality

What can you do to have good air quality in your attic?

  • Bird and animal proof your attic. 

  • Seal any gaps leading to living spaces, such as around light fixtures or heating and air-conditioning vents. You may want to contact a heating and air-conditioning contractor to do this for you.

  • Determine cause of wet or warped walls, studs or flooring. 

  • Repair cause (construction faults or storm damage) of problem and replace damaged insulation and structures. Check your homeowner’s insurance policy. Damages may be covered. If you do not own your home, notify the landlord as soon as you discover the problem.


Man scrubbing mold off a wall.

Laundry Room Air Quality

What should you do have good air quality in your laundry room?

  • Pull the washing machine away from the wall. Use the flashlight to look for plumbing leaks. Tighten pipes and hoses if needed. Clean the floor before replacing the washing machine. 

  • Pull the dryer away from the wall. Use the flashlight to check the exhaust hose. It should be vented to the outside of the house. Turn the dryer on while the exhaust hose is still attached to the wall. Then go outside your home and find the exterior vent. Do you feel warm air coming out? If so, that’s good news. If it is weak or you don’t feel any air at all, you have a problem that needs to be fixed. Either your exhaust hose is clogged with lint or it is not properly vented to the outside of your home. Clean the floor and walls before replacing the dryer. 

  • Ask your landlord to keep your laundry facility neat and dry with plenty of fresh air ventilated into the area. 

  • Bleach is an airway irritant known to produce symptoms in some adults and children with asthma. Avoid using bleach. 

  • Use unscented laundry products.


close up of a tailpipe with dark cloudy emissions

Garage Air Quality

What should you do have good air quality in your laundry room?

  • Switch to electric or human powered lawn mowers, hedge cutters and other tools. 

  • Paint should never be stored in the garage; temperature extremes cause it to go bad rapidly. When finished painting a room, pour a small amount of paint into a clean glass jar with a tight-fitting lid. Label it with a date, color, manufacturer and room it was used in before storing in a part of your home where it will not be exposed to temperature changes. 

  • Dispose of unused lawn and garden powders, sprays and pellets. 

  • If using the garage for hobbies or fix-it projects, make sure it is well ventilated. 

  • Do not leave car running in garage.


Photo of Man smoking in dark with visible smoke

Why is it so important to have a smoke-free home?

Secondhand smoke is a mixture of the smoke given off by the burning end of a cigarette, pipe, or cigar, and the smoke exhaled by smokers. It contains more than 4,000 substances, several of which are known to cause lung cancer in humans or animals.

Children are particularly vulnerable to secondhand smoke because they are still developing physically, have higher breathing rates than adults, and have little control over their indoor environments. Children exposed to high doses of secondhand smoke run the highest risk of having damaging health effects. 

If you smoke at home, consider how it affects your and/or your child’s health: 

More frequent and severe asthma attacks

Secondhand smoke irritates the airways and triggers asthma symptoms. Children with asthma who breathe secondhand smoke have more severe asthma episodes and lower lung function than children with asthma who are not exposed to smoke. Inhaling secondhand smoke may actually cause asthma in some children. A study in the American Journal of Respiratory and Critical Care Medicine found that the number of children diagnosed with asthma at age 6 or younger was twice as high in families who smoked as in nonsmoking families.

Higher risk of lower respiratory tract infections (bronchitis and pneumonia) 

Secondhand smoke exposure causes 150,000 to 300,000 lower respiratory tract infections every year in children 18 months or younger. It can result in as many as 15,000 hospitalizations per year. Secondhand smoke can also aggravate sinusitis, bronchitis and chronic respiratory problems like cough and postnasal drip.

More frequent ear infections

Inhaled secondhand smoke irritates the Eustachian tube. This is the tube connecting the back of the nose with the middle ear. This can cause a build-up of fluid in the middle ear. 

Greater risk of Sudden Infant Death Syndrome (SIDS)

Mothers who smoke while pregnant are more likely to have their babies die of SIDS. Babies who are around secondhand smoke after birth are also more likely to die of SIDS than children who are not around secondhand smoke.

See Related Pages

Reviewed by:
William E. Berger, MD, FACAAI, is a board-certified allergist and immunologist who serves as a media spokesperson and Chair of the Medical Advisory Council for Allergy & Asthma Network. He is a Distinguished Fellow and Past President (2002-03) of the American College of Allergy, Asthma & Immunology (ACAAI).