Office buildings continue to be a source of health complaints and
disease for many workers. Since the early studies in the 1980's, awareness of
the problem has grown and more workers have recognized the link between their
health symptoms and air pollutants in their buildings. As indoor air quality
in offices has been further studied, it has become clear that the problem is
complicated and the health and cost implications are significant.
In many buildings, occupant complaints of building related symptoms are
caused by uncomfortable temperatures, dryness, or high humidity. The American
Society of Heating Refrigeration and Air Conditioning Engineers (ASHRAE) has a
voluntary standard, "ASHRAE Standard 55-1992 Thermal Conditions for Human
Occupancy", which has recommendations for summer and winter temperatures (see
Building related symptoms and comfort can also be affected by office
lighting, ergonomic issues, and job stress.
THE LACK OF OUTSIDE AIR
In many cases, poor indoor air quality is a result of an inadequate
supply of outside (fresh) air. When buildings do not receive enough outside
air, pollutants can build up in the office air. These pollutants include
volatile organic compounds (VOCs) released from office equipment, office
furniture, carpeting, and other building materials.
New buildings usually
have the highest levels of VOCs because all the new materials in the
building release chemicals. After six months most new materials will have
off-gassed, releasing most of the chemicals into the air. Many manufacturers
now produce materials such as carpets, paint, and furniture which minimize
Studies have shown that in new buildings or buildings with inadequate
outside air, the buildup of VOCs can often lead to many occupants experiencing
symptoms of headache, fatigue, and eye or throat irritation.
are often called sick building syndrome, or tight building syndrome. The
symptoms almost always disappear a short time after the person leaves the
building. Often only a few sensitive persons will have symptoms at first,
but more people experience problems as the pollutants continue to build up in
the air. There are always some people that do not have any symptoms even in
severely under-ventilated buildings.
How Do Buildings Get Outside Air ?
In older buildings outside air is often supplied by openable windows.
This is often a difficult way to provide outside air since it can result in
cold or hot temperatures near the windows and the outside air may not reach
interior offices without windows. In order to keep comfortable temperatures
and evenly distribute outside air, engineers design and install building
ventilation systems (see the CWA fact sheet "HVAC Systems").
system provides a mixture of air taken from the outdoors and recirculated
from offices. The introduction of outside air minimizes the buildup of
pollutants. During very cold or hot weather, the ventilation system will mix
less outdoor air into the system in order to keep building temperatures
comfortable. When ventilation systems take in too little outdoor air, air
pollutants build up.
How Much Is Enough Outside Air ?
ASHRAE published a voluntary standard "ASHRAE 62-1989 Ventilation for
Acceptable Indoor Air Quality" in 1989. This guideline recommends that the
ventilation system in typical office buildings provide 20 cubic feet per
minute of outside air per office occupant. This standard was originally
intended to control pollutants and odors produced by people; however, in most
situations, it also seems to work well at controlling pollutants produced by
Under normal conditions, the ASHRAE recommended ventilation
rate can control pollutants from carpets, building materials, furniture, and
pollutants from most office materials and equipment.
A quick way to estimate the amount of outside air provided to a building
is to measure carbon dioxide, which is exhaled by people and is also found
naturally outside. Carbon dioxide normally exists in the outdoor air at a
concentration of 300 to 400 parts per million (ppm). Exhaled breath has a
concentration of 38,000 ppm.
In office buildings which are underventilated or overcrowded, carbon
dioxide levels build up. When carbon dioxide exceeds 1000 parts per million
(ppm), it usually means the office does not receive enough outside air.
However, even when carbon dioxide levels are below 1000 ppm, it does not
necessarily mean that the building receives enough outside air. Carbon
dioxide builds slowly even in severely under-ventilated offices and
measurements taken in the early morning may be well below 1000 ppm. This
measurement may lead to the incorrect conclusion that the ventilation is
adequate. Another problem is that carbon dioxide is produced by people and
not by the building.
An unoccupied problem area will always have low carbon
dioxide levels even though the air quality is terrible. It is also possible
that the ventilation system delivers adequate outside air maintaining low
carbon dioxide levels, but it is still not enough to overcome some strong
What Are Strong Sources of Office Building Pollutants?
There are a number of possible strong sources of building pollutants
which cannot be controlled by comfort ventilation alone.
Table 2 gives a
summary of strong pollutant sources. Many of these strong pollutant sources
can be controlled by one of the following methods: local exhaust ventilation
to capture the pollutants at their source, maintaining the room at a negative
pressure (under a lower pressure than the surrounding areas), air filtration
to remove the pollutant, removal of the source, or integrated pest management
to reduce the use of pesticides.
Combustion products released Carbon monoxide which can cause
by improperly functioning hot headaches, nausea, dizziness, and is
water heaters and boilers, sometimes fatal; also nitrogen oxides,
automobiles in parking garages, particulate matter, and volatile
trucks at loading docks. organic compounds.
Kitchens and rest rooms Odors
Laboratories Chemical vapors and gases
Photography darkroom Chemical vapors and gases
Large scale copiers Ozone, heat and toner dust
Blue print copiers Ammonia
Smoking areas Second-hand cigarette smoke contains
irritant gases, particulate matter, and
nicotine; it has been identified as a
Maintenance Oils, lubricants, cleaners, paints,
Print shop Inks and solvent-based cleaners
Construction activit Dusts, volatile organic compounds,
Pesticide applications. Pesticides, which are toxic and are
often mixed with volatile organic
Bioaerosols: Some buildings Airborne contaminants called bioaerosols
become a breeding ground which, when inhaled, can cause
for biological organisms allergy reactions and other illnesses.
such as molds, bacteria,
insects, rodents,and dust mites.
What about Polluted Outdoor Air ?
In some cases, the ventilation system brings in outside air that is
already polluted. When outside air inlets are located next to parking areas,
loading docks, bus stops, sanitary vents, exhaust stacks from boilers, etc.,
the pollutants are drawn into the ventilation system. This often results in
contaminated air in the building which may contain carbon monoxide or other
toxic pollutants. Most ventilation systems do not have filters that will
remove carbon monoxide, nitrogen oxides, or other chemical gases or vapors.
It is essential that buildings are designed so that the ventilation system
draws in outside air from a clean source .
The best source of outside air is
an air intake located low on the roof at least 20 feet from contamination
Building air quality studies have increasingly implicated bioaerosols as
a major source of building air quality problems. The presence of elevated
bacteria, fungal fragments, and spores are associated with allergy symptoms,
humidifier fever, and respiratory infections.
The presence of water is the most important factor in the growth and
multiplication of microbiological organisms in buildings. Water leakage from
roof and pipe leaks, ground water, and condensation which severely wets porous
building materials will promote the growth of molds.
Ventilation fans can
often have water and slime accumulate in the cooling coil drip pan or in the
ducts adjacent to cooling coils. This slime contains high levels of bacteria
and molds which can become airborne and be transported through the ventilation
Elevated levels of certain bacteria in the air can lead to fever, joint
aches, headache, and respiratory disease. Molds play an important role in
causing allergy symptoms similar to hay fever and asthma. Some people can
develop severe respiratory problems called hypersensitivity pneumonitis.
Molds release spores into the air. In heavily water-damaged buildings
where mold contamination is widespread, mold spore levels can often be 10 to
100 times higher than what is normally present outdoors. The molds normally
present outdoors generally don't cause problems for people, but the types of
molds that grow on wet building materials are associated with allergies.
Some species of mold, such as Aspergillus versicolor and Stachybotrys
chartarum, produce toxic chemicals (mycotoxins) which may cause health effects
including dermatitis, recurring cold or flu like symptoms, sore throat,
fatigue, diarrhea, and altered immune system function. Both of these mold
species grow well on water damaged paper in sheetrock and ceiling tiles.
Inhalation of mycotoxins is becoming recognized as a major indoor air quality
Buildings with persistent rodent or cockroach infestation have can
become a problem for some people. Mice and rats have proteins in their urine
which can cause allergic symptoms and contribute to asthma in persons with
Warm or hot water in buildings can be a reservoir for Legionnella
pneumophila bacteria. These are bacteria found world-wide which can grow in
domestic hot water systems, condenser water in cooling towers, and
humidification systems. Inhalation of the bacteria can cause Legionnaires
disease, a severe case of pneumonia, or Pontiac fever, a flu-like illness
which is not fatal.
The risk of developing these diseases is affected by
factors such as the length of time people are exposed, the amount of bacteria
in the air, and the health status of the exposed person. The occurrence of
Legionella pneumophila in buildings can be minimized by heating domestic water
to 140 � F, and following appropriate operating and maintenance procedures for
cooling tower water.
Many indoor air quality (IAQ) problems in buildings can be identified
by carefully inspecting the building without measuring specific pollutants in
air. Complaint buildings often have a number of problems such as ineffective
ventilation, insufficient outside air supply, poor housekeeping, water leaks,
and problems related to poor equipment maintenance.
Building occupants should begin by evaluating complaints and symptoms in
the office staff by distributing a questionnaire.
The questionnaire should be
designed to identify types of complaints or symptoms, timing patterns, and
where complaints occur.
Locate the supply air vents in the office and tape tissue paper at the
vent as a visual indicator of air flow. Look for evidence of water leaks and
list those areas where visible water damage has occurred. For example, if
carpeting has been flooded in the past, and remained wet over a number of
days, it is a likely source of mold problems.
More advanced IAQ investigations involve an inspection of the
ventilation system including the outside air inlets, filters, drip pans, and
Investigators also measure the amount of outside air drawn
in by the ventilation system and investigate how well the ventilation air is
distributed throughout the occupied space.
Typical equipment used in an advanced IAQ investigation include a carbon
dioxide meter, carbon monoxide meter, and equipment to measure temperature and
relative humidity. Ventilation smoke tubes can be used to give a visual
indication of air flow from supply diffusers and into return or exhaust
diffusers. A ventilation flow hood is used for accurately measuring the
supply of air delivered from a ceiling diffuser.
A pitot tube or thermal
anemometer is needed to measure air flow through a duct or into an outside air
intake on a fan unit. Air sampling is useful only if a specific contaminant is
Where water leaks are suspected and visible water damage is not evident,
a moisture meter is helpful for determining whether walls or ceilings are damp
or wet. A visual inspection of water-damaged areas and a building history of
water damage is the best way to identify bioaerosol problems. Laboratory
analysis of bulk samples of suspect water-damaged materials can be useful in
certain circumstances. Air sampling is not useful in most instances.
HOW ARE BUILDINGS WITH INDOOR AIR QUALITY PROBLEMS CORRECTED ?
Indoor air quality problems can be corrected either through improvements
in ventilation, improved filtration, or removal of pollutant sources.
Where problems with inadequate outside air are identified, it is often
quite simple to adjust the ventilation system to take in additional air.
Sometimes the ventilation system needs balancing in order to better distribute
air to all areas, or the installation of exhaust ventilation in special use
areas is needed. Duct cleaning may also be necessary to remove excess dirt
inside the duct work; the proposed cleaning methods should be reviewed to
determine their effectiveness.
When outdoor pollutants are a problem it is sometimes possible to
High efficiency filters can remove pollen, mold spores,
bacteria or other dusts. HVAC systems should use medium efficiency filters as
a minimum. Filters should be inspected and changed regularly. Depending on
the type of filter, the changeout interval may range from 3 to 18 months.
Deep bed activated charcoal filters can remove volatile organic vapors;
however these require frequent maintenance and replacement
When mold problems are a problem it is usually necessary to remove the
source of moldy material.
Contaminated porous material such as sheetrock,
ceiling tiles and insulation should be carefully removed under controlled
conditions. Methods similar to asbestos removal are recommended. Treatment of
water- damaged porous materials with biocides such as chlorine bleach does not
eliminate the spores, fungal fragments, or mycotoxins. These materials will
continue to cause allergies and other symptoms. The contaminated materials
must be carefully removed under controlled conditions and the dust cleaned up
with HEPA filter-equipped vacuum cleaners. Future water leaks must also be
prevented in order to prevent additional microbiological growth. Before
installing new materials it is essential to repair all wall, roof and pipe
There are no OSHA standards or other regulations covering office indoor
air quality in most states. (New Jersey is an exception for public
employees.) The levels of volatile organic compounds in problem buildings are
almost always below the OSHA permissible exposure limits, and there are no
recommended or regulatory standards for molds, bacteria, or other
allergy-causing bioaerosols in buildings.
Therefore, solving IAQ problems in offices becomes a matter of
The following are several steps to try to correct indoor air
* Document the problem by a questionnaire survey and inspection of the
workplace (if possible);
* Discuss the findings with co-workers, your Local Union and the CWA District
1 NYS Health and Safety Project and formulate demands;
* Organize a IAQ committee or health and safety committee;
* File a complaint with management;
* Begin the grievance process;
* Participate in all important meetings and workplace inspections;
* Be persistent.
A successful solution to indoor air quality problems usually involves
employees, management, building maintenance, the employer health and safety
department, and often outside consultants.
For further information see the CWA fact sheet "Organizing to Solve IAQ
Problems," or contact your local union or the CWA District 1 NYS Health and
Safety Project at (212) 509-6994.
This fact sheet was written by Edward A. Olmstead, CIH.
It is published
by the CWA District 1 NYS Health and Safety Project with partial funding from
New York State Department of Labor Hazard Abatement Board Contract #C007987.
The opinions expressed are not necessarily those of the NYS Department of
NYS Health and Safety Project
CWA District 1
80 Pine Street, 37th floor
New York, NY 10005
Most house plants can remove a variety of toxins (up to 95%).
NASA research found the following to be particularly effective at cleansing air: | Boston fern: removes formaldehyde | Dracaena Janet Graig: removes trichloroethylene | Dwarf date palm: removes xylene | Ficus alii: helps remove various toxins | Lady palm: improves indoor air quality | Peace Lily: removes various alcohols, benzene (highly cancer-causing), and trichloroethylene
According to a NASA study published in 1989 house plants are very efficient at purifying the air of indoor environments - both in the comfort of your private home... or in the interior of a space craft. The report found that common house plants can remove up to 87 percent of toxins (such as paint or adhesive fumes) in 24 hours. And house plants produce plenty of oxygen: altogether a breath of fresh air. NASA recommends to keep up to 10 good size plants (quote) in a 800 to 1000 square foot home. pdf download of the original NASA. gov research (click). The study also includes information on solvent risks.
The US Environmental Protection Agency, EPA, the American Lung Association, the World Health Organization and other public health and environmental organizations view indoor air pollution as one of the greatest risks to human health. Most of our exposure to environmental pollutants occurs by breathing the air indoors. These pollutants come from activities, products and materials we use every day. The air in our homes, schools and offices can be 2 to 5 times more polluted, and in some cases 100 times more polluted, than outdoor air. Indoor air quality is a significant concern, because when the hours spent sleeping, working in offices or at school are added up, people on average spend the vast majority of their time indoors where they are repeatedly exposed to indoor air pollutants. In fact, the US Environmental Protection Agency (USEPA) estimates that the average person receives 72 percent of their chemical exposure at home, which means the very places most people consider safest paradoxically exposes them to the greatest amounts of potentially hazardous pollutants.