Breathing easier in the United States -- Habitat for Humanity Int'l 1

Breathing easier in the United States

By Barbara Daugherty

In the United States, homeowners are increasingly concerned about the indoor air quality of their homes.

In fact, according to the Environmental Protection Agency (EPA), indoor air pollution is one of the five most urgent environmental problems facing the United States.

Research provides strong evidence that characteristics of buildings and their indoor environments influence the prevalence of several adverse health effects.

These include communicable respiratory disease (e.g., common colds and influenza), allergy and asthma symptoms, and acute sick building syndrome (SBS) symptoms such as headaches, and irritation of the eyes, nose, throat, and skin. Recent studies reveal that buildings with good overall environmental quality can reduce the rate of respiratory disease, allergy, asthma and sick building symptoms.

The potential decreases in adverse health effects from improvements in indoor environments are estimated to be 10 to 30 percent for infectious respiratory disease, allergy and asthma symptoms and 20 to 50 percent for sick building syndrome symptoms. (Fisk and Rosenfeld)

Indoor pollution sources that release gases or particles into the air are the primary cause of indoor air quality problems in homes.

Inadequate ventilation can increase indoor pollutant levels by not bringing in enough outdoor air to dilute emissions from indoor sources and by not carrying indoor air pollutants out of the home. High temperature and humidity levels can also increase concentrations of some pollutants.

Habitat for Humanity International’s U.S. Construction Standards recommend that all Habitat houses meet or exceed the Energy Star and healthy indoor air quality standards.

The Energy Star program focuses on tight energy-efficient homes which promote better indoor air quality than a leaky home.

One reason is reduced condensation which can lead to mold growth. Another reason is control. In a leaky home, outdoor air enters the house — through cracks, unsealed joints, and penetrations— intermittently, depending largely on the weather. Sometimes there will be too much leakage, resulting in a drafty house. Other times there won't be enough, resulting in a stuffy house. Mechanical ventilation in a well-insulated, well-sealed house, however, can exhaust pollutants and bring in outdoor air in a planned way. This makes a house both comfortable and energy efficient.

In addition, U. S. Affiliates are encouraged to choose construction materials and interior finish products with zero or low emissions to improve indoor air quality.

Many building materials and cleaning/maintenance products emit toxic gases, such as volatile organic compounds (VOC) and formaldehyde. These gases can have a detrimental impact on occupants' health and productivity. It is important to remember when building a tight house and using combustion based appliances (furnace, dryer and stove) that careful ventilation be used to prevent back drafting and carbon monoxide infiltration. Many codes demand that furnaces be installed in a sealed combustion closet and/or power vented with a fresh air vent.

It is also important to provide adequate ventilation and a high-efficiency, in-duct filtration system.

Heating and cooling systems that ensure adequate ventilation and proper filtration can have a dramatic and positive impact on indoor air quality. A central exhaust vent that can be wired on a timer or to run 24 hours a day may be a consideration. Indoor microbial contamination can be prevented through selection of materials resistant to microbial growth, by providing effective drainage from the roof and surrounding landscape, installing adequate ventilation in bathrooms, allowing proper drainage of air-conditioning coils, and designing other building systems to control humidity.

Habitat for Humanity has an easy-to-read home maintenance booklet available for Habitat homeowners on how to maintain a healthier home. You can download these booklets in either English (1MB .pdf) or Spanish (1MB .pdf).

Habitat for Humanity affiliates across the United States are dedicated to building simple, decent and HEALTHY homes to enhance the lives of Habitat homeowners.

Maintaining a healthy home: some tips for homeowners

To keep moisture levels low:

  • Run kitchen and bathroom fans when cooking and showering.
  • Clean mold off of interior surfaces quickly.
  • Clean and repair water leaks within 24 hours.
  • Use a dehumidifier if humidity is above 50 percent.


To improve air quality:

  • Change HVAC air filters every 30 days.
  • Avoid secondhand smoke, which can be a contributory cause of asthma and breathing problems.

Source: Fisk, W.J. and Rosenfeld, A.H. 1997, 'Estimates of Improved Productivity and Health from Better Indoor Environments Indoor Air, vol. 7 (3), pp. 158-172.

This research is supported by the DOE's, Office of Building Technology, State and Community Programs

Barbara Daugherty is a coordinator of U.S. Field operations.