Indoor Air/Environmental Quality
The Indoor Environmental Quality (IEQ) Unit provides consultation, technical assistance, education, and training to local health departments, housing code enforcement officials, other state agencies, health care providers, and the public regarding environmental conditions in homes, schools and workplaces that can lead to poor IEQ and impact health.

General Information

IEQ in Homes 


 IEQ in Schools

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IEQ in Workplaces


IEQ in Day Cares

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Air Fresheners

Air Purifiers


Air purifiers are devices that remove some of the particles and chemicals from indoor air.  Certain types that intentionally produce ozone, called ozone generators, many pose a health danger.

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Asbestos is a mineral fiber used in many products such as pipe insulation and floor tiles that can be harmful to health. It is a regulated substance.


Refer to the DPH Asbestos Program for more information.


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Azogue is liquid (metallic) mercury that is often used by those practicing rituals associated with Esperitismo, Santeria, and other Haitian, Caribbean, and Latino cultural practices. The use of azogue can be very dangerous to your health.


Information for Health Care Providers:

Information for the Public:

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Cleaning and Disinfecting Indoors

Routine cleaning and disinfecting practices are reviewed for residences, public spaces, and schools in these fact sheets from the CT DPH.  Information about choosing EPA registered disinfectant products and why this is important is explained. Additionally, cleaning and disinfection strategies are discussed for infectious disease outbreaks in non-healthcare environments.

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Construction Activities  

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Formaldehyde is a common indoor air pollutant chemical used in many products including particle board and plywood.  It can cause respiratory and skin irritation. Formaldehyde is a carcinogen.

Green Living/Green Cleaning


A healthy environment is an important component of our physical and mental well-being.  We can keep our families and the environment healthy by limiting exposure to harmful substances. We can do this by making informed choices about what we use and consume. Choose  “green” or “environmentally preferred products” (EPP), which have less effect on human health and the environment than other products that serve the same purpose.


“Green” or “environmentally preferable products” (EPP) are products that have a reduced effect on human health and the environment when compared to other products that serve the same purpose. The term “green” and the characteristics that have come to define it are currently not regulated.  Some products are now being marketed as “green” that may not be any better for the environment than regular products.  Check for the certification logo.


In a Home

In a Daycare

In a School

Buy It, Clean It, Build It
Buy It:  There are a number of non-profit, third-party certification organizations that evaluate products using established science-based criteria. They test products independently for environmental impact, health effects and performance. 
Clean It: Green Cleaning encompasses the use of less toxic cleaning products, best practice cleaning methods, and updated materials and equipment such as microfiber cloths and mops.  
Build ItSustainable buildings are comfortable, safe, and productive, avoid depleting resources like energy, water, and raw materials, and prevent environmental degradation throughout the structure’s life cycle.  

The fundamental principles of sustainable building design are: Optimizing the building site; optimizing energy; protecting and conserving water; using environmentally preferable products (EPPs); enhancing indoor environmental quality; optimizing operational and maintenance practices.



Industrial Hygienists and other Indoor Environmental Quality consultants vary in their training and experience. Choose someone with experience and success with evaluating your type of situation.  Before hiring, ask for and check credentials and references.  Note that the State of Connecticut does not license or certify mold assessors, inspectors, or mold abatement professionals.*


*The Connecticut Department of Public Health does have licensing and certification requirements for asbestos, lead, and radon professionals.


Licensed Home Inspectors

Home inspectors may be helpful in identifying certain IEQ contaminants like moisture, rodent and insect infestations, and problems with furnaces that may lead to back drafting and carbon monoxide poisoning.  Home inspectors have a variety of backgrounds and expertise.  Choose someone with experience and success with evaluating your type of situation.  Before hiring, ask for and check credentials and references. Note that Home Inspectors must be licensed and registered with the Connecticut Department of Consumer Protection.

Mold Abatement Contractors

If you decide to hire a contractor to remove moldy building materials and contents, the work area should be contained or segregated from non-contaminated areas. CT DPH recommends that those purchasing mold abatement services insist that contractors follow the Connecticut Guidelines for Mold Abatement Contractors as a condition of payment (this document can be found on our Mold webpage). Note that these are guidelines and not enforceable regulations. The state of Connecticut does not license or certify mold abatement contractors. There are professional trade organizations that offer mold abatement training, credentialing, and provide contractor lists for consumers. Before hiring, request and check credentials and references. Note that if the abatement involves more than simple cleaning, the contractor must be licensed and registered as a home improvement contractor with the Connecticut Department of Consumer Protection.


Insulation and Your Home: Health Considerations: Choosing among the variety of insulation materials and installers can be a daunting task. This insulation fact sheet focuses on three key things that can affect your health. Understanding these concepts will help you to become a more informed buyer and avoid common pitfalls that can lead to health problems.

Spray Polyurethane Foam Insulation - Spray Polyurethane Foam (SPF) Insulation is one of a number of insulation products on the market.  It is made by combining liquid chemicals that react quickly, expanding to form a foam material.
Urea Formaldehyde Foam Insulation - Urea Formaldehyde Foam Insulation (UFFI) was a type of insulation produced in the 1970’s that emitted high levels of formaldehyde.  It was banned from use in 1981. Homes that had UFFI installed no longer present a health risk because formaldehyde emissions from the product have decayed away during the past 30-40 years.
Lead is a heavy metal found in paint (before 1978) that can cause developmental problems in children.  There are regulations regarding abatement of lead. Refer to the DPH Lead Poisoning and Prevention Program for more information.

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Mercury is a shiny, silvery metal that is a liquid at room temperature. The airborne vapor that is emitted is dangerous when it is inhaled, posing a possible health risk if there is a mercury spill in your home, office, or school.

Don't Mess With Mercury (Video)

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Molds are fungi that cause the breakdown of organic matter such as leaves, paper, and wood. While all indoor environments have some mold that comes in from the outdoors, damp/moist indoor environments encourage mold growth indoors. This can lead to respiratory problems in building occupants.  For more information about mold, visit our Mold website.

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Pest Management /IPM (Integrated Pest Management)


The best way to control pests is by using Integrated Pest Management or IPM. IPM is a common-sense approach that focuses on managing pests with the least possible impact on people, property and the environment.  It incorporates measures for the long-term prevention of pests or their damage that look at environmental factors that affect the pest and its ability to thrive.  Pests need habitats that provide air, moisture, food and shelter.  For more information click on the following links:

Radon is a colorless, odorless, radioactive gas found naturally in soils and rocks that can cause lung cancer. Refer to the DPH Radon Program for more information.

Temperature plays a large role in whether people are satisfied with their indoor environment.  The combination of human and environmental factors leads to comfort levels that effect productivity, health, and well being.
Extreme Heat:
Heating in Buildings:


Tobacco Smoke

Tobacco smoke is a known carcinogen that affects both smokers and those around them (secondhand smoke). Refer to the DPH Tobacco Use Prevention and Control Program for more information.

Ventilation systems draw in fresh [outdoor] air, condition it (heat or cool it), mix it with indoor air, and remove indoor air contaminants before circulating it throughout the building.  In buildings with mechanical ventilation systems, room temperature and ventilation are strongly related.  Inadequate ventilation can lead to occupant discomfort and decreased productivity.

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Volatile Organic Compounds (VOCs)


VOCs are carbon-based  compounds that evaporate easily.  VOCs include a wide variety of chemicals, some of which may have short- and long-term adverse health effects.  Examples of VOCs include paints, cleaning supplies, and pesticides.  Concentrations of many VOCs are consistently higher indoors than outdoors.