INDIANA
UNIVERSITY-PURDUE UNIVERSITY at INDIANAPOLIS
IUPUI
• Department of Environmental Health and Safety
•
620 Union Drive, Room 043, Indianapolis, Indiana
46202
Indoor
Air Quality
Complaints
related to indoor air quality increased significantly
following energy conservation measures instituted
in the early seventies. A move was made to "tighten"
buildings by reducing air leakage and minimizing
the volume of outside air brought in. These actions
allowed contaminants to build-up and recirculate
inside.
Numerous
studies have documented a wide range of different
chemical and biological contaminants present in
indoor environments. Unfortunately, the extent to
which these contaminants may affect your health
is difficult to determine. Indoor air contaminants
are typically present in very low concentrations
making it extremely difficult to accurately measure
and identify specific pollutants or to establish
any kind of defensible cause and effect relationship
from exposure.
Comfort
Issues
Historically,
office environmental concerns focused only on comfort
issues such as temperature, humidity, drafts, stuffiness,
and odor control. Building designers worried about
oxygen depletion and carbon dioxide buildup but
found that simple odor control measures provided
enough ventilation to offset these concerns.
Health
Issues
More
recently, attention has concentrated on possible health
effects associated with exposure to low concentrations
of indoor air contaminants. Investigations have shown
that many physical or psychological symptoms have
resulted from these types of exposures particularly
among sensitive individuals. To complicate the issue,
workers in an office environment are typically much
more sensitive to slight environmental changes such
as temperature, odor, and light than other workers
in general industry. These sensitivities make it difficult
to separate factors that affect comfort from those
which may affect health.
Regulations
On
a national level, Federal OSHA has looked into developing
a specific standard on "Occupational Exposure
to Indoor Air Pollutants" but thus far this effort
has been unsuccessful.
Guidelines
The American Society of Heating, Refrigerating and
Air-Conditioning Engineers (ASHRAE) developed a standard
for IAQ titled "Ventilation for Acceptable Indoor
Air Quality." This standard is only a recommended
guideline but it has been widely used by Industrial
Hygienists and Engineers
Typical
Complaints and Symptoms of Indoor Air Pollutants
At one end of the spectrum are the transient or non-specific
symptoms and complaints such as common colds that
may simply be brought from home or passed around the
building from person to person. At the other end is
a problem known as "mass psychogenic disease"
caused by suggestions that the air is bad and people
should be feeling sick. In-between are a number of
conditions which may be the result of poor ventilation
and/or causative agents (chemical or biological contaminants)
which genuinely cause "sick building syndrome"
and "building related illnesses".
IAQ
problems, real or imagined, seem to always affect
morale, efficiency, and attendance. A difficulty in
solving IAQ problems is that symptoms and complaints
are typically non-specific and episodic. Often, only
a select number of people are affected by a problem
and their complaints may come and go. Many persons
report their symptoms subside after they vacate a
building and reappear upon entry. Medical diagnosis
can also be inconclusive. The most common symptoms
and complaints attributed to poor IAQ include:
• |
Upper
respiratory irritation, coughing, congestion |
• |
Itching,
watering eyes |
• |
Sinus
irritation, sneezing |
• |
Headache, dizziness, nausea |
• |
Fatigue,
listlessness, inability to concentrate |
• |
Shortness
of breath |
• |
Discomfort
of a non-specific nature |
| |
|
This
list of complaints is typically associated with the
phenomenon known as sick building syndrome. A difficulty
in resolving sick building syndrome is that these
same symptoms can also originate from any number of
possible sources including common colds, allergies,
smoking, poor lighting, poor ergonomics, or stressful
work loads.
Specific
IAQ Illnesses
On the other hand there are
some very specific illnesses directly associated with
indoor air contamination. Each of the diseases listed
below with the exception of asthma are typically associated
with building related illnesses. These include:
Humidifier fever – (mild flu-like symptoms,
no deaths)
Pontiac fever – (similar to humidifier fever,
non-pneumonia, no deaths)
Legionnaires' disease – (pneumonia, high fever,
10-20% mortality; incidence is low)
Hypersensitivity Pneumonitis – (flu-like symptoms,
recurrent pneumonia, chest tightness, immunological
sensitization to microorganisms in building environment)
Asthma – (normally affects 3 - 4% of population
and can be complicated by poor air quality)
Sources
and Types of Indoor Air Pollutants
The
National Institute for Occupational Safety and Health
(NIOSH), in studies of over 500 IAQ Health Hazard
Evaluations, categorized the major sources or factors
involved with IAQ problems as follows:
| Problem
Origin |
|
Typical
Sources |
| Inadequate
Building Ventilation Systems, |
52% |
Lack
of outside air, poor air distribution, uncomfortable
temperature and humidity, contaminant sources
inside the system |
| Contaminants
Originating Inside Building |
20% |
Solvent
vapors, dusts, formaldehyde, building materials,
furnishings |
| Unknown
Causes |
12% |
Unidentified
sources |
| Outdoor
Contaminants Entering Building |
11% |
Motor
vehicle exhaust, pollen, fungi, smoke, construction |
| Microbiological
Agents |
5% |
Bioaerosols,
Legionella, |
Chemicals
and Carbon Dioxide
People
give off body odors and exhale carbon dioxide. Over
the course of a day, the background levels of carbon
dioxide may rise, often reaching concentrations exceeding
1,000 ppm. Carbon dioxide itself is not harmful at
this concentration but is a good indicator that other
contaminants of greater concern, (e.g., carbon monoxide,
hydrocarbon vapors, aerosols, tobacco smoke, and microorganisms)
may also build up. In the absence of specific pollutant
sources, carbon dioxide is used simply to indicate
the adequacy of outside air supply.
Two major IAQ sources extensively referenced as contaminants
of particular concern are environmental tobacco smoke
(ETS) and radon gas.
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