Indoor air quality (IAQ) is one of six metrics which when
combined with others, influences the total definition of indoor
environmental quality (IEQ).
IAQ in of itself is not a proxy for IEQ which is written
IEQ = TCQ + IAQ + ISQ +ILQ
TCQ = Thermal comfort
IAQ = Indoor air quality
ISQ = Indoor sound quality
ILQ = Indoor lighting quality
IOQ = Indoor odor quality
IVQ = Indoor vibration quality
Items of Competency
IAQ investigations can be simple and basic
requiring low to moderate skill levels, or complex and anomalous
requiring several IAQ investigators with different and advanced
We will focus on the general practitioner
involved in residential construction noting that these skills
sets apply to all types of projects. As a bare minimum, a
generalist in IAQ investigations should have an adequate
indoor environmental quality, which call for a basic
human physiology, chemistry, biology and physics as
material and earth sciences. With these knowledge areas,
the investigator should understand the relationships between the
various outdoor and indoor environmental concerns influencing
the occupant. Table 1 organizes a list of topics
that the IAQ practitioner should cover when doing basic
investigations. The examples given are by no means complete but
are provided to indicate the scope of knowledge required.
Investigators should also have basic skills in interviewing
techniques, building design and construction practices; basic
understanding of heating and cooling systems and appliances; use
of IAQ measurement equipment; interpretation of IAQ data; and
technical report writing.
The objective of the interviewing process is to
elicit occupant responses for the purposes of gathering
information which can be used later to develop hypotheses. This
process requires professional communications meaning that verbal
dialogue and written reports may be legally regulated. This is
especially true if the investigation is part of a legal
proceeding or where property and personal harm has occurred.
Government legislation regarding the collection and sharing of
personal information must also be considered and respected. It
is important that the professional interviewer understands that
they should not attempt to manipulate or lead the conversation
in directions that may be construed as self serving, as might be
the case of an investigator with interests in selling filtration
or dehumidification equipment.
Building Design and Construction Practices
Excluding discussion on post construction
occupant operation of a home, the source of many IAQ problems
can be attributed to the land development, poor designs
including choices in materials and faulty assemblies. In order
to understand the problems with an existing building, the
investigator has to understand what constitutes good design and
construction practices. All of the items in Table 1 find
themselves somewhere in the study of construction.
HVAC and Appliances
Unless proven otherwise, an IAQ problem will
HVAC problem regardless of the cause. This is why the
IAQ generalist has to be aware of all the other potential
elements so he/she can reduce the list of concerns through a
process of elimination. The HVAC systems and appliances may very
well be the cause and solution. For this reason the investigator
should be aware of the principles of HVAC design and operation.
This includes ventilation standards, and the capabilities and
limitations of various air quality equipment such as filtration,
humidification and dehumidification devices.
IAQ Measurement Equipment
The generalist should be able to identify the
simplest of IAQ challenges with basic instrumentation. This
might include handheld devices for measuring particulate, carbon
monoxide, temperature, pressure and moisture or they might
include passive samplers for sampling such things as radon. Some
may also have the skills to use blower doors and thermography
equipment. These are all building and material science-related
devices and should be part of one’s inventory of investigative
tools. Beyond the application of these basic tools are
instruments and samplers used by field and laboratory personnel
who usually specialize in industrial hygiene or microbiology.
Interpretation of Data
Results from basic instruments are immediate and
can be interpreted during the investigation. However, having the
results and interpretation does not provide cause. For example,
a high moisture reading from basement flooring can verify a
reason for mould but it won’t identify the source of the
moisture. So the use of measurement tools goes hand in hand with
one's overall knowledge base.
Technical Report Writing
The investigator will need to organize and report
on the findings and recommendations in a well thought out, clear
and concise format. This document might just be exchanged
between the occupant and investigator to complete the terms of
the contract or it could very likely find itself as evidence in
legal proceedings. The quality of the report in terms of its
presentation, technical accuracy, thoroughness, grammar and
spelling will serve as a perpetual record representing the
professionalism of the individual involved in the investigation.
Poorly written reports, including those that are inaccurate,
misleading or self serving are a reflection of the investigative
firm–it is best to approach every communication as if the
document or dialogue will at some point become public domain.
The above provides an outline of basic
competencies for a general practitioner in IAQ investigations
and is by no means exhaustive. It does not for example discuss
skills needed for corrective measures or the application of
safety precautions needed during investigations. These come
through years of training and experience.