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Office Indoor Air Quality

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 Table 1).


Table 1. ASHRAE Temperature Recommendations -  Winter - Summer - Relative Temperatures - Temperatures - Humidity (deg. F) (deg. F)
30% 68.5-76 74-80 40% 68.5-75.5 73.5-79.5 50% 68.5-74.5 73-79 60% 68-74 72.5-78


Building related symptoms and comfort can also be affected by office lighting, ergonomic issues, and job stress.


 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 chemical outgassing. 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.

These symptoms 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").

The ventilation 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 the building.

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 pollutant sources. 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.

Combustion exhaust 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 human carcinogen. Maintenance Oils, lubricants, cleaners, paints, thinners, etc. Print shop Inks and solvent-based cleaners Construction activit Dusts, volatile organic compounds, irritant gases Pesticide applications. Pesticides, which are toxic and are often mixed with volatile organic compounds 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 sources.



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 system. 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 problem. 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 allergies. Legionnaire's Disease 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 ventilation ducts.

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 suspected. 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.



Indoor air quality problems can be corrected either through improvements in ventilation, improved filtration, or removal of pollutant sources. Ventilation Improvement 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. Filtration When outdoor pollutants are a problem it is sometimes possible to improve filtration.

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 Source Removal 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 leaks.



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 organizing.

The following are several steps to try to correct indoor air quality problems: * 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 Labor. 1998. NYS Health and Safety Project CWA District 1 80 Pine Street, 37th floor New York, NY 10005 (212) 509-6994.



NASA puts Plants into
Space for Health


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.

Plants That Clean Indoor Air, Which Ones to Choose,
by Deborah Mitchell

Overview of Indoor Air Quality (IAQ).     


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.

Most of this article was originally printed for Art Hazard News, © copyright Center for Safety in the Arts 1998. It appears on
nontoxicprint courtesy of the Health in the Arts Program, University of Illinois at Chicago, who have curated a collection of these articles from their archive which are still relevant to artists today.