IAQ FAQs

Frequently Asked Questions About IAQ

General IAQ Information
Mold and Allergen Problems in Homes and Buildings
Chemical Problems in Homes and Buildings
Basic IAQ Facts

General IAQ Information

  1. How does indoor air compare to outdoor air?

  • Indoor air can be as much as 100 times more polluted than outside air. These pollutants pose serious environmental exposures to people.

  • Studies by the US Environmental Protection Agency (EPA) and other researchers have found that volatile organic compounds (VOCs) are common in the indoor environment and that their levels may be ten to thousands of times higher indoors than found in the outdoor air. There may be anywhere from 50 up to hundreds of individual VOCs in an indoor air sample.

  1. What are the general types of indoor air pollutants? Click on the links to get more detailed information on each type of indoor pollutant.

  1. What are the sources of indoor air pollution? The following are some common sources of indoor pollutants.

  1. Why is there so much concern about indoor air quality?

  • Indoor air pollutants pose serious environmental exposures to people, especially as people spend more than 90 percent of their time indoors. Exposure can cause some people to experience adverse health effects and poor IAQ in commercial buildings can lower worker productivity. In addition, studies have shown that poor IAQ can adversely impact learning among school children, in addition to making allergy and asthma symptoms worse.

  • The US Environmental Protection Agency cites IAQ as one of the top five environmental health risks and indoor air pollution as one of the greatest risks to human health.

  1. How do I know if the IAQ in my home is good?

Before testing your IAQ, there are a number of indications you can consider to determine if you have indoor air quality problems. Click below for the indications in different indoor environments:

  1. Can I determine the exent of a potential IAQ problem and/or prevent problems in my home or building?

Careful assessment of potential IAQ problems is best undertaken by an IAQ expert as different indoor environments and different problems require different approaches. If you do not currently have IAQ problems, there are certain measures you can take to prevent them Click below for overview of assessment and prevention of IAQ problems in different indoor environments:

  1. Is duct cleaning useful?

  • The EPA has said that there is no proof that duct cleaning actually prevents health problems. That is because there are bigger sources of pollutants in the home than just dirty air ducts.

  1. When should air ducts be cleaned?

  • Before you think about having your ducts cleaned, make sure that dirty ducts are the cause of your indoor air problems. There are times when ducts should be cleaned; for example:

    • You can see a lot of mold growing in the ducts or other parts of the ventilation system.

    • There is vermin, such as rodents or insects, infesting your air ducts.

    • The ducts are clogged with so much dirt and debris that it is being released into the home from your supply registers.

      As you can see, if any of these conditions exists, there are much bigger problems present than just dirt in your ducts. The sources of these problems need to be taken care of first since this would indicate more than just a dirty air duct problem.

  1. Are green products available?

    Several companies have started making "green" products as well as setting up "green" programs. A few are listed below:

  • The GREENGUARD™ Environmental Institute identifies specific products that have been tested for their chemical and particle emissions and found to be acceptable for the indoor environment.

  • The Carpet and Rug Institute established an IAQ labeling program to encourage manufacturers to lower and maintain chemical emissions from carpet and adhesives within very low ranges. Those products meeting the criteria are awarded the Green IAQ Label.

  1. Where can I get more information?

    If you would like more infomration than can be found in the Aerias AQS IAQ Resource Center, click on the Resource Links tab above for recommended resources that can provide additional information.

Mold and Allergen Problems in Homes and Buildings

  1. What are molds?

  • Mold and fungi are organisms with rigid cell walls but no chlorophyll, which grow wherever there is both water and a source of organic nutrition. Certain chemicals called mycotoxins that can produce VOCs such as acetone, ethanol, and isopropanol are produced by some molds and might be toxic to people and animals.

  1. What makes mold grow?

  • Molds will grow anywhere indoors where there is moisture and a food source. Many building materials provide this needed food source-many consist of cellulose materials that are particularly suitable for mold growth when they are wet. Mold and fungi generally need a relative humidity of at least 60 percent to give them enough moisture to survive or significant moisture intrusion, regardless of humidity.

  1. Are there molds in every indoor environment?

  • Molds are everywhere, in the surface layer of antarctic rocks, on Mediterranean marbles and old dirty car fenders, as well as in mattress and floor dust. Everyone is exposed to molds everyday.

  • Most molds in indoor air come in with fresh outdoor air. The air inside most buildings has fewer molds than outdoor air. Indoor mold growth means indoor moisture problems (humidity, leaks, cold surfaces, spills or improper drying after wet cleaning)

  1. What molds are typical?

  • The most common indoor molds are Cladosporium, Penicillium, Aspergillus, and Alternaria. Click here to access the mold glossary (or on the tab in the navigation menu at the top of this page) for more information about mold species and terms associated with mold and mold remediation and assessment.

  1. What molds are harmful and how can you tell?

  • Any molds that are growing in an indoor environment can potentially be harmful. It is, however, important to know what species of mold is growing. In general, moldy materials will contain many different molds. The only way to find out which molds are growing in your house or office is to have special testing conducted to know the exact concentration and type of mold.  Click here to access the mold glossary (or on the tab in the navigation menu at the top of this page) for more information about mold species and terms associated with mold and mold remediation and assessment.

  • There are several ways that mold can cause health effects: allergies, nonspecific inflammation, toxins, infections; some of these are poorly understood.

  1. Is Stachybotrys still a problem after the CDC retraction?

  • The 2000 Centers for Disease Control and Prevention (CDC) report was not a retraction, but more appropriately, a clarification of issues from earlier publications. Exposure that leads to a potentially toxic dose should be avoided. What is that exposure? Stay tuned, we do not know yet. Prudence would seem to dictate that you want to be careful with Stachy, treat it like any toxic substance: keep it contained (do not let it grow in the first place), if it spills clean it up (remediate any mold growth), and use appropriate worker protection (determine the level of protection according to American Council of Governmental Industrial Hygienists (ACGIH) and/or New York City guidelines for mold remediation).

  1. How do I tell which molds are growing?

  • Either through direct evidence (visual and/or microscopic exam), or by looking for indirect evidence from cultural results or air sampling.  Click here to access the mold glossary (or on the tab in the navigation menu at the top of this page) for more information about mold species and terms associated with mold and mold remediation and assessment.

  1. How can you test for mold in the home?

  • There are many ways to test for mold; no single way works for all cases, each way has a limitation. If there is mold growth in a building, a knowledgeable investigator using a good lab can usually detect it.

  • Before hiring a building investigator, ask about their training in indoor air, and in mold sampling, whether they use an accredited lab and check their references.

  • Test results should emphasize whether there is evidence of growth and what mold is found rather than providing mold counts, which alone are useless.

  • Click here to access the mold glossary (or on the tab in the navigation menu at the top of this page) for more information about mold species and terms associated with mold and mold remediation and assessment.

  1. How can you fix mold problems?

  • Identify and correct the moisture source (e.g. leaky roof or window).

  • Clean up wet areas within 24 hours since mold will grow within 24 to 48 hours.

  • Wear personal protection like eye protection, dust mask, and rubber gloves before beginning any minor cleanup.

  • Remove any moldy materials by bagging and discarding them.

  • Wash the area with soap and water before disinfecting.

  • Disinfect the area using a solution of 10 percent household bleach (e.g., 1 to 1½ cup bleach per gallon of water). Using bleach straight from the bottle will not be more effective.

  • Apply disinfectant with a sponge or spray bottle and let it sit for 15 to 20 minutes before cleaning.

  • Let cleaned areas dry overnight and use ample ventilation.

  • Dead molds are just as undesirable as live molds (removal is more important than killing).

  • Click here to access the mold glossary (or on the tab in the navigation menu at the top of this page) for more information about mold species and terms associated with mold and mold remediation and assessment. 

  1. What are the important indoor allergens?

  • Dust mite, mold, insect and animal allergens can all contribute to poor indoor air quality. They can make you sneeze, trigger allergic reactions, cause rashes, watery eyes, coughing, dizziness, lethargy, breathing difficulties, and digestive problems.

  1. How can I test for allergens?

  • There are test kits available in which dust is collected into a filter and is then tested for various molds and allergens. The report details the allergen types and levels measured, and the types of molds identified.

  • You may need to contact a professional to further investigate your home or school, on site, to pinpoint the source of the harmful molds and/or allergens. Based on the findings, procedures for controlling and preventing molds and allergens within your home or school can be recommended.

  1. How can I reduce allergens in my house?

  • Control the sources of indoor air problems

    • Clean your home regularly

    • Control sources of moisture

    • Wash and brush any indoor pets

    • Drain and clean humidifiers regularly and use distilled water in smaller units.

  • Have good and proper ventilation with enough outside air

    • Use local exhaust ventilation that vents to the outside.

    • Vent all gas-burning appliances to the outside.

    • Keep air ducts clean and dry.

    • Change air filters regularly and use a high-efficiency filter, if the ventilation system is powerful enough for one.

    • Don't block any intake or return vents in offices.

  • Keep humidity levels between 40 percent and 60 percent.

  • Filter the air

Chemical Problems in Homes and Buildings

  1. What chemicals are a problem?

  • Volatile chemicals are released by common products such as furnishings, construction materials, consumer products and cleaners. They are sources of irritation to people. Formaldehyde is released by wood products, textiles, and paper materials.

  1. What are typical levels of these chemicals?

  • Each building will contain anywhere from two-dozen to hundreds of individual VOCs. The total level (TVOC) will range from 200 µg/m3 to 1000 µg/m3. Formaldehyde typically ranges from 20 µg/m3 to 70 µg/m3. Also, visit the Premium Content section of this site and sign up for free access to detailed information and data on VOCs in indoor environments and VOCs emitted from product categories. 

  1. What health symptoms result from VOC exposure?

  • Levels higher than 200 µg/m3 TVOC and 60 µg/m3 of formaldehyde may result in irritation to people such as burning or itching of eyes or nose, stuffy nose, sore or burning throat or headache.

  1. What are some common VOCs found?

  • Toluene, formaldehyde, styrene, limonene, isopropanol, pentane, tetrachloroethylene, ethanol, decane and undecane.

  • Also, visit the Premium Content section of this site and sign up for free access to detailed information and data on VOCs in indoor environments and VOCs emitted from product categories. 

  1. How do I control the levels of VOCs?

  • The best way is to reduce the sources. Purchase low-emitting materials and furnishings; air out the home when new materials are brought in; use exhaust fans when cooking; avoid use of fragranced materials, deodorizers, and aerosol sprays; store construction chemicals outside of the building.

  1. How can I test for VOCs?

  • There are test kits available to easily measure formaldehyde and VOCs. The report details levels and compares them to available guidelines and standards. ONLY tests specifically designed for IAQ measurements can be used.

Basic Facts about Indoor Air Quality 

General IAQ

  • Americans spend more than 90 percent of their time indoors.

  • Indoor air can be as much as 100 times more polluted than outside air. These pollutants pose serious environmental exposures to people.

  • The US Environmental Protection Agency (EPA) calls indoor air pollution one of the greatest risks to human health.

  • Indoor air can pose a risk to human health, including asthma, cancer, reproductive and developmental problems.

  • US companies could save as much as $200 billion in worker performance improvements by creating offices with better indoor air.

  • The average household of four adds between three and six gallons of water to the indoor air in a day.

  • One of every 15 homes in the US has radon levels above the EPA's recommended action level.

Building-Related Symptoms (also called Sick Building Syndrome)

  • A US Environmental Protection Agency report found that illness and lost productivity due to indoor air pollution, commonly called "sick building syndrome" (SBS) or building-related symptoms (BRS), costs businesses $60 billion annually.

  • Occupants of buildings with BRS complain of eye, nose and throat irritation, headaches, dry cough, dry or itchy skin, dizziness, nausea, difficulty in concentrating, fatigue and sensitivity to odors.

  • Heating, ventilating and air-conditioning (HVAC) systems are a primary cause of the majority of BRS problems.

Health Effects Associated With IAQ

  • Allergies, which affect about 20 pecent of the population, and asthma, a debilitating condition, are worsened by indoor air pollution. Asthma has increased 160 percent in the past 15 years.

  • Building-related illnesses include sinusitis, bronchitis, asthma, humidifier fever, dermatitis, Legionnaires' Disease, and Pontiac Fever.

  • Asthma is the sixth ranking chronic condition in the US and the leading serious chronic illness of children in the US.

  • Approxicmately 40 million Americans are affected by allergies.

  • An estimated 17 million Americans have from asthma.

  • An estimated 1500 people die each year from carbon monoxide poisoning.

  • Legionnaires' disease affects 10,000 to 15,000 people each year

  • Environmental tobacco smoke (ETS or secondhand smoke) causes 3,000 lung cancer deaths in nonsmoking Americans each year.

  • Toxins from indoor mold and bacteria can result in effects ranging from short-term irritation to immunosuppression to cancer

  • Smoking is the third leading cause of preventable death in the United States today.

  • Numerous indoor contaminants are carcinogens (i.e. benzene and radon or likely to cause cancer (i.e. certain pesticides, chlorinated solvents, and aldehydes).

Mold

  • The types and levels of mold outdoors fluctuate from morning to evening and from day to day. Mold assessments in indoor air must compare the types of molds found indoors to those outdoors. Click here to access the mold glossary (or on the tab in the navigation menu at the top of this page) for more information about mold species and terms associated with mold and mold remediation and assessment.

  • Also, visit the Premium Content section of this site and sign up for free access to detailed information and data on mold in indoor environments.

  • If mold is growing in a building, it may or may not be the cause of a specific complaint.

Ventilation

  • A growing number of buildings today receive inadequate amounts of fresh air because of energy conservation measures. To effectively control air pollution, buildings must be properly ventilated with adequate amounts of outdoor air, and internal pollutant sources must be controlled.

  • Ventilation-related problems are the most frequently encountered cause of IAQ problems.

IAQ in Schools and in Workplaces

  • An estimated 20 percent of all schools in the US have indoor air problems and 25 percent have unsatisfactory ventilation.

  • Nearly one in five schools in the US has at least one room with radon levels above the EPA's recommendation.

  • Health symptoms are experienced in the workplace by 20 percent to 30 percent of US office workers, and are a source of complaints in schools.

  • Dissatisfaction rate among employees increased by about 20 percent when the office space was of the open floor plan type.

  • One out of every three Americans who work indoors are exposed to poor indoor air quality.

  • The federal government has no effective standards for IAQ in offices.

  • Identifying and controlling sources of indoor pollutants are the most direct control options for combating indoor air problems. With this consideration, manufacturers may need to redesign products to reduce pollutant emissions.

  • The State of Washington was the first state government to institute indoor air quality guidelines for construction materials, office furnishings, and equipment to be used in newly constructed buildings. Other states are developing such standards.

  • Click here for more information about IAQ in schools and click here for more information about IAQ and workplaces.  This information also can be accessed by clicking on The IAQ Resource tab in the navigation menu at the top of this page.