TSI Alnor EBT731, EBT730 Handbook
Indoor Air Quality Handbook
.
A Practical Guide to Indoor
Air Quality Investigations
ENERGY AND COMFORT
ENERGY AND COMFORT
Indoor Air Quality
TRUST. SCIENCE. INNOVATION
Indoor Air Quality Handbook
A Practical Guide
to Indoor Air Quality
Investigations
Copyright © 2011 by TSI Incorporated
Contents
Introduction ..................................................................................................................................................... 1
Building Design and Operation ........................................................................................................................ 2
Effects of Poor Quality Air ............................................................................................................................... 3
Types of Pollutants ......................................................................................................................................... 4
Controlling Sources of Pollutants ..................................................................................................................... 4
Investigating Indoor Air Quality ...................................................................................................................... 5
Measurements Used to Determine Air Quality ............................................................................................... 6
Comfort Issues and Productivity ...................................................................................................................... 6
Temperature ...................................................................................................................... 7
Humidity ............................................................................................................................. 7
Air Movement and Flow ..................................................................................................... 8
Velocity .......................................................................................................................... 8
Volume .......................................................................................................................... 8
Ventilation ..................................................................................................................... 9
Health and Safety Issues .............................................................................................................................. 11
Carbon Monoxide ............................................................................................................ 11
Airborne Particles ............................................................................................................ 11
Ultrafine Particles ............................................................................................................ 13
Bioaerosols ...................................................................................................................... 14
Chemicals in Aerosol Form ............................................................................................. 15
Light, Noise, Vibration, Ergonomics, Odors, etc. ............................................................ 15
Conclusion .................................................................................................................................................. 16
Sources for Information Relating to Indoor Air Quality Evaluations ........................................................... 17
Standards and Guidelines ............................................................................................................................. 18
IAQ Instruments from TSI .............................................................................................................................. 19
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Indoor Air Quality Handbook
Introduction
Concern about indoor air quality (IAQ) and the study of air quality issues is a fairly recent phenomenon. Some of
the earliest documented studies occurred in Scandinavia in the mid-1960s and were focused primarily on
thermal comfort issues. For the first decade or so, IAQ studies primarily involved comparing indoor air to outdoor
air. The level of outdoor pollution was a chief concern and the goal was to ensure that indoor air was of better
quality than the outdoor air subjected to pollutants.
As studies increased in sophistication, other
measurable factors came into play. Building
construction materials and techniques
changed radically. A reduction in natural
ventilation, or "fresh" air, in the interest of
saving energy became a concern and,
finally, people realized that pollutants could
actually originate within a building. The
World Health Organization (WHO) estimated
that more than 30 percent of all commercial
buildings have significant IAQ problems.
For many years, people working in areas
with known exposure to potential hazards have had a number of options available with respect to personal
protection, including equipment such as respirators, hard hats, gloves, goggles, and more. Indoor air quality as
discussed here, however, applies to areas or situations where people are generally unaware of potential hazards.
They normally do not expect to need protection and this is why the subject has become so important.
In some cases, the quality of
indoor air can be critical.
Since the energy crisis of the 1970s, buildings have been constructed much tighter, significantly lowering the
exchange of indoor and outdoor air. The strategy has been to save energy costs by re-circulating internal air and
minimizing the need to heat, cool or condition outdoor air. Although considerable savings are realized with this
strategy, unwanted contaminants can and do become trapped in these tight enclosures.
Recent developments in construction materials have resulted in the use of more synthetics and composites,
which can affect air quality. Radical changes in technology have led to innovations such as computers and
photocopiers that provide greater efficiencies and time savings, but they can also affect the quality of indoor air.
These potentially adverse effects are further complicated by the fact that people are spending more time than
ever indoors, up to 90 percent according to estimates by the U.S. Environmental Protection Agency (EPA). It is
easy to understand why there is a growing concern about the quality of the air we breathe.
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Indoor Air Quality Handbook
People are spending more than
90 percent of their time indoors.
As a result of these and other factors, totally new terminology has come into use and the topic is gaining more
attention every day. Some examples include:
• Sick Building Syndrome (SBS)—where more than 30 percent of occupants experience adverse
effects while in the building, but no clinically diagnosed disease is found.
• Building Related Illness (BRI)—general term for a medically diagnosable illness caused by, or
related to, building occupancy.
• Multiple Chemical Sensitivity (MCS) or Environmental Illness (EI)—a controversial condition
where an individual has or develops sensitivity to even low levels of certain chemicals due to extended
exposure.
Bottom line, the quality of indoor air can and does impact productivity, personal comfort, building maintenance
costs and even health and safety, either positively or negatively depending on how air quality is managed.
Building Design and Operation
Ensuring satisfactory air quality requires a good understanding of the building itself. The design, physical layout,
mechanical systems, equipment and space usage are all essential elements that can affect air quality. The air
distribution system requires particular attention. How does outdoor air get in? Is the air filtered? How does air
circulate throughout the building?
Understand how spaces are designed and where walls, furnishings and equipment are located. Keep in mind the
building layout can create physical barriers that impede the flow and distribution of air, which can impact the
quality of air in a given area.
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Indoor Air Quality Handbook
Unwanted contaminants move from areas
of relative positive pressure to those of relative negative
pressure through a path of least resistance.
Consider pollutant "pathways" which allow airborne gases and particles to migrate to different areas of the
building. These pathways may not be obvious and are not necessarily physically defined. Pollutants can travel by
air movement or pressure differential where unwanted contaminants move from areas of relative positive
pressure to those of relative negative pressure through a path of least resistance.
Effects of Poor Quality Air
In this handbook, when we talk about factors affecting air quality, we are beyond the already proven hazardous
materials where exposure limits have been set and personal protective equipment prescribed. Here, we address
what would be considered "normal" air in offices, schools, libraries, churches, hospitals and other interior spaces
where we spend time without expecting to face any risks.
Different people react differently to
different levels of different substances.
As bizarre as it sounds, there is no universal reaction to a measured amount of a
particular material. People simply have different tolerance levels. It is difficult to
assign standards or even guidelines to set acceptable versus unacceptable levels of
literally thousands of airborne pollutants.
Many indoor air contaminants are actually new, bred from the ever-changing technology that so many of us are
exposed to daily. From alternative energy sources to photocopiers, we are generating new pollutants at an everincreasing pace.
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Indoor Air Quality Handbook
Typical symptoms caused by air quality problems vary greatly according to an individual's sensitivity and may
include chills, sweating, eye irritation, allergies, coughing, sneezing, nausea, fatigue, skin irritation, breathing
difficulty and others. In extreme cases, personal reactions actually reach the point where an individual cannot
function, when exposed to adverse air conditions.
Unfortunately, there are virtually no Federal regulations governing exposure levels in non-industrial indoor
environments. Indoor air quality is a growing concern and gaining attention. It is prudent to take a proactive
approach and address any issues that could potentially have adverse affects on indoor air
quality.
Types of Pollutants
General pollutant types that affect air quality include:
• Biological—bacteria, fungi, viruses, molds, pollen, animal hair, dander and excrement are examples of
common biological pollutants that can impact air quality.
• Chemical—cleaners, solvents, fuels, adhesives, various combustion by-products and emissions from
furnishings and floor and wall coverings are typical examples of airborne chemicals.
• Particles and Aerosols—are solids or liquids that are light enough to be suspended in air. Particles are
classified in three general categories—coarse, fine and ultrafine—and are derived from dust, construction
activities, printing, photocopying, manufacturing processes, smoking, combustion and some chemical
reactions in which vapors condense to form particles. These can be categorized as dust, smoke, mist, fume
and condensates.
Controlling Sources of Pollutants
In a typical building, pollutants fall into two
source categories: those that enter the building
from the outside and those generated within
the building itself. Both include a wide variety
of types and origins. Outdoor sources can
include building stack exhaust, vehicle
emissions, industrial processes and
construction activity as well as many others.
Internal sources include maintenance or
housekeeping activities, chemicals, cleaners,
solvents, building renovations, new furnishings,
new finishes, office equipment and various
occupant activities.
Pollutant sources must be located and controlled to ensure good indoor air quality. Keep in mind that both
sources and pathways are essential components that must be well understood for effective problem remediation.
Pathways are created as pollutants travel by air movement or from relative positive to relative negative pressure
areas through even the smallest of openings. Several methods for managing a pollutant source are available
once the source is identified, including:
• Removing the source
• Repairing the source so it no longer contributes pollutants
• Isolating the source with a physical barrier
• Isolating the source using air pressure differential
• Minimizing the time people are exposed
• Diluting pollutants and removing them from the building with increased ventilation
• Increasing filtration to clean the air and remove pollutants
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