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Solving Indoor Air Quality Problems

There are many steps that can improve the quality of indoor air. Some of the most common measures are described below.

1. Remove or reduce the source of contaminants by:

  • prohibiting smoking indoors or limiting smoking to areas that are under negative pressure and exhausted to the outside;

  • locating fresh air intakes away from polluted areas or exhaust vents;

  • installing local exhaust ventilation for machines and operations (photocopiers, printing equipment, laboratory procedures, etc.) that give off odors and contaminants;

  • steam cleaning carpets and partitions, and vacuuming again with a high-efficiency particulate air filter vacuum; and

  • properly storing all chemicals in an area with exhaust ventilation to the outside.

 

2. Increase ventilation rates.

The rate of air flow in a general office setting should, at a minimum, be 20 cubic feet of air per minute (cfm) per occupant. This recommendation comes from the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) standard 62-1989. The National Institute of Occupational Safety and Health (NIOSH) also recommends this as a minimum rate of air flow.

 

3. Maintain relative humidity between 30 and 60 percent.

In addition to providing comfort, humidity between 30 and 60 percent helps to control mold and mildew growth.

 

4. Clean and maintain the HVAC system regularly.

Maintenance of the HVAC systems includes cleaning and disinfecting duct work, supply diffusers and return vents. They should be cleaned, disinfected and open; make sure the fan is operating properly.

 

The Basics of an HVAC System


A properly designed and functioning HVAC system will provide a comfortable environment. The elements of the HVAC system include:
  • outdoor air intake

  • mixed-air plenum and outdoor air control

  • air filters

  • heating and cooling coils

  • humidification and/or dehumidification

  • supply fans

  • exhaust fans

  • duct work

  • cooling tower

  • self-contained heating and cooling unit

  • controls

  • boiler

  • water chiller

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    Guidelines for duct cleaning include:

    • schedule duct cleaning when the building is not occupied to prevent exposure to chemicals and loosened particles;

    • keep the system under negative air pressure and drawing the air through a vacuum collection system;

    • use only HEPA (high-efficiency particle air) vacuuming equipment in occupied spaces;

    • avoid the use of sealants to cover interior duct work surfaces;

    • clean and sanitize coils and drip pans to reduce biological agents; and

    • remove or replace water-damaged porous materials in the duct work or other air handling system parts.

     

    Indoor air quality standards

    There is no OSHA standard for indoor air quality. OSHA does have standards to limit exposure to specific chemicals. However, it is very unusual when there is such a high level of one chemical that it is causing widespread problems and complaints.

     

    Recommended standards for indoor air quality


    The American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) has issued recommendations for indoor air quality:
    ASHRAE Standard 62-1989 — Ventilation for Acceptable Indoor Air Quality
    ASHRAE Standard 55-1981 — Thermal Environmental Conditions for Human Occupancy

    ASHRAE Standard 52-1976 — Methods of Testing Air-Cleaning Devices Used in General Ventilation for Removing Particulate Matter

     

    See the following publications and websites for more information


    AFSCME, Interior Air Quality, a Checklist for Identifying and Improving IAQ Problems

    American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE)

    Environmental Protection Agency, Building Air Quality

    Environmental Protection Agency, Building Air Quality Action Plan

    National Institute for Occupational Safety and Health, Guidance for Indoor Air Quality Investigations, 1987

    National Air Duct Cleaners Association, 1528 K Street, N.W., Washington D.C. 20005, (202) 737-8847

     

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