NC State Extension Publications

Indoor Air Quality in Your Home

Skip to Indoor Air Quality in Your Home

Did you know that the air inside buildings is nearly always more polluted than outside air? Did you know that most people now spend 80-90% of their lives indoors, breathing that more-polluted air?

Indoor air pollution is a high-ranked health risk. How it affects your health depends on the amounts and types of pollutants in your air and how often you breathe them. Air pollutants can harm some people more than others. The risks are greatest for sick people, the elderly, the very young and peole with allergies.

There is much you can do to make your indoor air healthier. The first step is to be aware of what might be in your indoor air and how it could harm your health.

Biologicals and Radon

Skip to Biologicals and Radon


  • Humid air, damp things, and wet ground under your home can lead to molds, dust mites, and bacteria growing in your home.
  • Fine dust in the air you breathe can include bits of animal dander, insects, dust mites, and pollen.
  • Radon is a radioactive soil gas that can seep in through cracks and build up in homes. Radon problems are common in North Carolina.

Health Risks:

  • Dust mites, mold, insect droppings, and pollen in the air can cause asthma attacks and allergies.
  • Bacteria and viruses can cause diseases.
  • Radon causes lung cancer.

What You Can Do:

  • Use bathroom and kitchen exhaust fans to get rid of wet air.
  • Vent clothes dryers to the outdoors.
  • Make sure the soil under your home stays dry and that rainwater flows away from your home.
  • If you have a flood or leak, remove soaked carpets and materials right away.
  • Check and empty the drip pans of refrigerators.
  • Make certain air conditioner drains are functioning properly.
  • If your home is made energy-efficient and airtight, make sure the air conditioner is not oversized. Get a load calculation from your air conditioning dealer or electric company. Oversized air conditioners do not take enough moisture out of the air.
  • Consider using a dehumidifier if the humidity stays too high.
  • Mop and wipe away dust.
  • Buy and use a HEPA vacuum cleaner.
  • If someone in your home has allergies, keep animals outside.
  • Wash bedsheets in hot water every two weeks to reduce dust mites.
  • Choose smooth flooring instead of carpeting to reduce dust mites.
  • Use washable area rugs.
  • Get your home tested for radon.

Combustion Pollutants

Skip to Combustion Pollutants

Source 1:

Tobacco smoke has more than 4,000 compounds in it, including carbon monoxide and formaldehyde. The air carries these pollutants all over your home. Fabrics and things in your home trap them long after you can't see any smoke.

Health Risks:

About 40 of the compounds in tobacco smoke could cause cancer. Breathing secondhand smoke causes thousands of lung cancer deaths each year. It also causes many children to suffer from bronchitis, pneumonia, ear infections, and asthma attacks.

Source 2:

Anything that burns a fuel makes carbon monoxide and other harmful pollutants. They can build up in indoor air if fuel-burning appliances and heaters have no vent to the outside or have leaky or clogged vents. Wet wood, smoldering fires, and yellow gas flames give off more pollution than normal. Car exhaust also can seep into homes.

Health Risks:

Breathing carbon monoxide starves the body of oxygen. You can't see or smell it. Large amounts are deadly. Symptoms are flu-like symptoms. Other combustion pollutants can irritate your eyes, nose, and throat. Over time, they can damage your lungs.

What You Can Do:

  • Don't let anyone smoke in your home. If that cannot be accomplished, limit smoking to one room. If you allow smoking in a room, keep the door closed, open a window, and put a fan in it to blow air to the outside. This will help keep the pollutants from spreading throughout your home.
  • Never smoke around children.
  • Keep gas heaters and appliances correctly adjusted. The flame should be blue.
  • Get your heaters, flues, and chimneys inspected and cleaned every year.
  • Don't use kerosene heaters indoors. If you must use a gas space heater that is not vented to the outdoors, open a window a little, keep inside doors wide open, and don't fall asleep.
  • Never use a charcoal grill indoors.
  • Use an exhaust fan or open a window when using a gas cooking stove.
  • Put good weatherstripping around the door from the home to the garage.
  • Never run the car in a closed garage.
  • Get a carbon monoxide alarm for your home.

Organic Gases and Pesticides

Skip to Organic Gases and Pesticides


Common products used in homes are made of many chemicals. Both natural and artificial chemicals can put harmful, volatile-organic-compound (VOC) gasses in your air. When you use them indoors, the level of harmful gases in the room can get very high. Even when containers are sealed, VOC gases can leak out into your air. Some building materials (like pressed wood) and decorative furnishings (carpets, fabrics, etc.) released unhealthy gases, especially when new and when the air is warm and humid.

Health Risks:

Over time, some VOC and chemical pesticides can cause cancer or damage the central nervous system. Some chemicals are very toxic and can harm you quickly. Some bother only people with allergies. Others have not been found to be harmful.

Warning labels on products tell you about serious known dangers. Some common symptoms are problems with eyes, nose, throat, vision, memory, and headaches.

What You Can Do:

  • Read labels carefully, and follow the directions.
  • If a label says you need "adequate ventilation," use the product outside if you can. If not, open all windows and use exhaust fans.
  • Store anything that makes fumes outside your home.
  • Safely get rid of old and unneeded chemicals, fuels, pesticides, paints, etc. Find out if your community has a hazardous household waste collection day and bring your items to this collection.
  • If your dry-cleaned clothes have a strong chemical smell, you may wish to try a different dry cleaner.
  • Don't use outdoor pesticides inside your home. Don't use any more than directed by the label. To cut your need for pesticides, keep your home clean and keep garbage outside in tight containers.
  • When needed, use baits, traps, and boric acid for pest control.
  • Bathe pets often.
  • Shop for less toxic types of products and building materials. Look for "low VOC" products.
  • When shopping for new carpet, look for a "green label" carpet tested for low emissions. Go outside when the carpet is being installed, and air out your home for three days after installing the new carpet.
  • If your home has a lot of pressed wood, try to keep the indoor air cool and dry.

Lead and Asbestos

Skip to Lead and Asbestos


Some homes built before 1978 and many homes built before 1960 have lead-based paint and asbestos materials. Floor tiles as recent as 1986 could have asbestos. If they are in good shape, there is usually little danger. Any kind of damage to those materials can put lead or asbestos dust into the air, however. Soil with lead in it can get inside and add lead dust to the indoor air.

Health Risks:

Breathing asbestos dust over a long time can lead to lung diseases, including lung cancer, mesothelioma, and asbestosis.

Breathing lead dust can harm nearly every system in the body. Lead is most dangerous to young children. Even very low levels in children can lower intelligence, cause behavior problems, and affect hearing. That type of damage can last all of their lives.

What Can You Do:

  • Before you remodel, renovate, or repair your home, find out if it has any lead-based paint or asbestos. You can find NC-certified lead professionals here: North Carolina Certified Lead Professionals. You can find North Carolina accredited asbestos professionals here: North Carolina Accredited Asbestos Disciplines
  • Do not sand, scrape, burn, or damage lead-based paint or asbestos materials. Leave them alone. If they must be removed, only workers trained and certified in safe removal methods should do the job. Hire only EPA/NC lead certified renovators for work on homes build before 1978; ask to see their certificate.
  • Wet wipe paint dust and loose paint chips with a solution of detergent to warm water. Wear disposable gloves. Throw away the cleaning rags and gloves in a sealed plastic bag.
  • Get more information about lead and asbestos in the home at the following sites:

For More Information

Skip to For More Information

To learn more about Indoor Air Quallity, visit the EPA's Indoor Air Quality siteor call 800-490-9198. Also, visit Indoor Pollutants and Sources.

For blood lead tests, medical advice, and treatment, visit your doctor or health department.

Adapted from Claudette Reichel, Be Aware of Your Indoor Air, LSU Ag Center.


Professor and Housing Specialist
Louisiana State University
State Program Leader for Family & Consumer Sciences & Professor
Agricultural & Human Sciences

Find more information at the following NC State Extension websites:

Publication date: Jan. 15, 2019

N.C. Cooperative Extension prohibits discrimination and harassment regardless of age, color, disability, family and marital status, gender identity, national origin, political beliefs, race, religion, sex (including pregnancy), sexual orientation and veteran status.