Cal Iaq

Hiring Professional Assistance to Solve an IAQ Problem
modified from: 
Building Air Quality: A Guide for Building Owners and Facility Managers
NIOSH and EPA, December
NIOSH Publication 91-114. 
Web site:


Many IAQ problems are simple to resolve when facility staff have been educated about the investigation process. In other cases, however, a time comes when outside assistance is needed. Professional help might be necessary or desirable in the following situations, among others:

You may be able to find help by looking in the yellow pages of your telephone book (e.g., under "Engineers", "Environmental Services", "Laboratories-Testing" or "Industrial Hygienists"). Local or State health or air pollution agencies may have lists of firms offering IAQ services in your area. It may also be useful to seek out referrals from other building management firms.

Local, State, or Federal government agencies may be able to provide expert assistance or direction in solving IAQ problems. It is particularly important to contact your local or State Health Department if you suspect that you have a serious building-related illness potentially linked to biological contamination in your building.

If available government agencies do not have personnel with the appropriate skills to assist in solving your IAQ problem, they may be able to direct you to firms in your area with experience in indoor air quality work. Note that even certified professionals from disciplines closely related to IAQ issues (such as industrial hygienists, ventilation engineers, and toxicologists) may not have the specific expertise needed to investigate and resolve indoor air problems. Individuals or groups that offer services in this evolving field should be questioned closely about their related experience and their proposed approach to your problem.

As with any hiring process, the better you know your own needs, the easier it will be to select a firm or individual to service those needs. Firms and individuals working in IAQ may come from a variety of disciplines. Typically, the skills of HVAC engineers and industrial hygienists are useful for this type of investigation, although input from other disciplines such as chemistry, chemical engineering, architecture, microbiology, or medicine may also be important. If problems other than indoor air quality are involved, experts in lighting, acoustic design, interior design, psychology, or other fields may be helpful in resolving occupant complaints about the indoor environment.


As you prepare to hire professional services in the area of indoor air quality, be aware it is a developing area of knowledge. Most consultants working in the field received their primary training in other areas. A variety of investigative methods may be employed, many of which are ineffective for resolving any but the most obvious situations. Inappropriately designed studies may lead to conclusions that are either false negative (e.g., falsely concludes that there is no problem associated with the building) or false positive (e.g., incorrectly attributes the cause to building conditions). Diagnostic outcomes to avoid include:

Considerable care should be exercised when interviewing potential consultants to avoid those subscribing to these strategies. A qualified IAQ investigator should have appropriate experience, demonstrate a broad understanding of indoor air quality problems and the conditions which can lead them, and use a phased diagnostic approach.


Most of the criteria used in selecting a professional to provide indoor air quality services are similar to those used for other professionals:

Experience. An EPA survey of firms providing IAQ services found that almost half had been providing IAQ diagnostic or mitigation services in non-industrial settings for ten or fewer years. Quality of Interview and Proposal. Several guidelines may be of assistance in hiring IAQ professionals. In some cases building investigators may have accumulated a breadth of knowledge. For example, a mechanical engineer and an industrial hygienist see buildings differently. However, a mechanical engineer with several years of experience in IAQ problem investigations may have seen enough health-related problems to cross the gap; likewise, an industrial hygienist with years of experience studying problems in an office setting may have considerable expertise in HVAC and other building mechanical systems.

Either in the proposal or in discussion, the consultant should:

Reputation. There are no Federal regulations covering professional services in the general field of indoor air quality, although some disciplines (e.g., engineers, industrial hygienists) whose practitioners work with IAQ problems have licensing and certification requirements.

Building owners and managers who suspect that they may have a problem with a specific pollutant (such as radon, asbestos, or lead) may be able to obtain assistance from local and State Health Departments. Government agencies and affected industries have developed training programs for contractors who diagnose or mitigate problems with these particular contaminants.

Firms should be asked to provide references from clients who have received comparable services. In exploring references, it is useful to ask about long-term follow-up. After the contract was completed, did the contractor remain in contact with the client to ensure that problems did not recur?

Knowledge of Local Codes and Regional Climate Conditions. Familiarity with State and local regulations and codes helps to avoid problems during mitigation. For example, in making changes to the HVAC system, it is important to conform to local building codes. Heating, cooling, and humidity control needs are different in different geographic regions, and can affect the selection of an appropriate mitigation approach. Getting assurances that all firms under consideration have this knowledge becomes particularly important if it becomes necessary to seek expertise from outside the local area.

Cost. It is impossible for this document to give specific guidance on the cost of professional services. If projected costs jump suddenly during the investigation process, the consultants should be able to justify that added cost. The budget will be influenced by a number of factors, including:

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