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Indoor Air Quality: 
An Old Problem Reappears

UE News, March & April 2001

By David Kotelchuck


Problems with polluted air and poor indoor air quality have been known for decades. But in  the past few decades these problems have grown much worse, especially for workers in offices, whether in office buildings or in-plant offices. And some of these problems, such as toxic mold growth, can affect people at any worksite.

What are some of the symptoms of poor indoor air quality?

  • They can be general, like headaches, unusual tiredness, dry or irritated throat, coughing, itching or burning eyes, skin irritation, or even dizziness or nausea. (Sometimes these symptoms are lumped together and called Sick Building Syndrome.)

  • They can be highly specific, like chest tightness, fever, chills, or muscle aches and pains. Some give rise to diagnosed illnesses or conditions such as Legionnaire’s Disease, occupational asthma and other respiratory diseases. (These are called Building Related Illnesses.)

What can cause these symptoms?

  • Toxic chemicals used in the workplace.

  • Toxic molds, which can grow in warm, moist areas, such as basements and air ducts.

  • Poorly designed or poorly maintained HVAC systems (heating, ventilation and air conditioning systems).

Let’s look at the above causes one at a time:

Toxic chemicals

Formaldehyde is a common office pollutant. As a chemical agent used to make plastics, synthetic fabrics and plywood, it is emitted by new rugs (at home as well as in the office), new office furniture, and partitions made with plywood. At low levels it causes eye, nose and throat irritation, and is particularly noticeable in poorly ventilated rooms in which new furniture and rugs have just been installed. When new items are installed in the office, open the windows and let the air out overnight or over the weekend, maybe even put an exhaust fan in the window to help ventilate the room. If the odor or irritation persists, insist that management get professional help, since formaldehyde is regulated by OSHA as a possible cancer agent.

Volatile Organic Compounds (VOCs) can build up in the workplace air and cause symptoms of Sick Building Syndrome. These can include, for example, solvents used in inks, paints, glues, rubber cement, felt pens and white-out fluids. In almost all cases the exposure levels of each of these compounds will be far below the individual levels permitted by OSHA (called PELs, permissible exposure levels). But remember, if the building managers don’t let in enough fresh outside air, these can persist in the building air, and eventually build up to bothersome levels. One way to avoid these buildups is to put particularly toxic operations like painting in separate, closed-off areas with their own exhaust ventilation systems (and with full protection for those doing the painting). Another helpful action is to put lids on all solvent containers when they are not in use — even small containers can emit lots of vapor when they are left open for a long time.

Rug and Floor Cleaning Chemicals: Many rug and floor-cleaning agents are sold in concentrated form, and have to be diluted before using. If they are not diluted properly, and used in more concentrated form, they can cause eye, nose and throat irritation. Also if not properly mixed, some rug cleaners can leave a coating of dust on the rugs. One such dusty chemical, sodium lauryl sulfate, causes an allergic response in many people. If you notice health problems soon after floor or rug cleanings, speak with the cleaning staff and see if the cleaning compounds are being diluted or mixed in the proper proportions.

Toxic Molds

Molds exist throughout the natural environment. To reproduce and live they emit tiny spores, which travel in outdoor and indoor air until they land on a nice damp indoor surface. If the surface they land on also contains materials they can digest, such as wood and wood products, carpets, ceiling tiles, paints, wallpaper, drywall, fabrics and foods, they have found a happy home and they grow and thrive.

Since molds can feed on such a wide range of materials, the key to mold control is moisture control. If moisture problems remain undiscovered or un-addressed, for example in the basements of buildings (or of homes), mold growth will often follow. When areas become water damaged, it is important to clean them up within 24 to 48 hours to prevent mold growth. Often absorbent materials, such as rugs and ceiling tiles, have to be replaced. Leaky plumbing needs to be fixed, and mold has to be cleaned off of hard surfaces with bleach and water (1 part chlorine bleach to 10 parts water — and don’t ever mix bleach with ammonia).

Most important of all, on a long-term basis, is to keep the humidity of all areas of the building low, say in the range of 30 to 50 percent humidity. This means improving ventilation in all parts of the building, particularly in potentially moist areas like basements; greater use of humidifiers and air-conditioners there; reducing condensation on cold surfaces like pipes, exterior walls and roofs by better insulating them; venting shower rooms and at home venting moisture from clothes driers.

A particularly dangerous type of mold, which has increasingly been found at many workplaces in recent years, is the mold called Stachybotrus chartarum (pronounced Stacky-bot-rus chart-a-rum). Sometimes it is also called Stachybotrus atra - the two are just different names for the same mold. This greenish-black mold releases a so-called mycotoxin into the air, to which many people are allergic. Many develop symptoms of hay-fever (nasal stuffing, eye irritation and wheezing) in its presence; others who already have asthma or some other chronic respiratory disorder can have trouble breathing and become infected and disabled from it. People who are under treatment for AIDS or HIV infection are also at risk of infection from these molds.

Stachybotrus likes to grow on high-cellulose, low-nitrogen materials like fiberboard, gypsum board and paper. So it is often found in libraries and rooms where papers are stored. If you find molds in your workplace, clean up the areas and reduce moisture levels, as suggested above — you really don’t need to identify the particular mold you are dealing with, they should all be treated as potentially dangerous.

(For more information on molds and Stachybotrus, go to the following CDC and EPA websites: and


The heating, ventilation and air-conditioning (HVAC) system of any plant or office building is the collection of heating, cooling and ventilating equipment for that building. When properly designed and operated, it should:

  • Control the temperature and humidity in the building to provide a decent, comfortable human working environment,

  • Distribute enough clean outdoor air to meet the ventilation needs of the people working inside, and

  • Remove odors and pollution from the air in the building.


During the past thirty years or so, many plants and office buildings have had troubles with this system, leading to drowsiness, headaches, allergies, respiratory and skin conditions. Above, we discussed some of the sources of indoor air pollution. Now we need to discuss the HVAC system, how to determine if it’s operating properly, and how to get it fixed. Remember, you don’t have to be an expert to decide if the system is doing its job, even though you may need one to get the system back in proper working order and replace worn-out or defective equipment.

Below are some questions to ask, and problems to look out for in your particular workroom, office or area of the plant:

Does your workplace have a ventilation system?

Many workplaces have a ventilation system which is not so much designed, but just sort of happens. This is especially true if the plant or building you are working in was built for another purpose, and then converted or adapted to its current uses. If you are working in a large plant area, with few or no walls or partitions, look at the number and sizes of exhaust fans along the walls and in the ceiling, and look at the number and sizes of the windows and doors which are supposed to let air in? Are there enough of them? Are they properly placed so that everyone working on the shop floor can get enough fresh air?

If you are working in a closed office or workroom, look around the room for air vents, usually small grills on the walls or floorboards, or diffuser panels in the ceiling. There should be two vents in each room, one to supply air and one to remove it. If you don’t have any vents then the only air movement and air replacement in the room has to come from open windows and open doors.

If you have only one vent, look for the other. The other one may be in the room next door with a small opening for air, say next to the window panel, connecting the two rooms. Or maybe there is only a partial barrier between offices and the air flows around or above the partition(s) from one office to the other. Or, of course, the other vent may be down the hall, and of no help for your room when the door is shut. Remember, air is a fluid which flows from one place to another — it can’t just enter or leave from your room through one single vent and stop there. If it really has no place else to go, it will just sit as stagnant pool with no air movement until the door or windows open.

Are the room vents supplying or removing air?

For the two vents in your room, or the two working together in connected, neighboring rooms, one (the supply vent) should be supplying air to the room(s) and the other (the exhaust vent) removing it. How can you tell which is which? Just put a piece of tissue paper up to the vent and see which way the air there is flowing. For the supply vent, it’s often useful to just tape the tissue to it, so you can always just look up and see if air is being supplied. (Some air-supply systems in large buildings are timed to go off after working hours. Make sure they don’t go off at 4 or 5 pm, when you or others are scheduled to work until 6 or when you have to work overtime or on Saturdays. If this is happening, speak to the building staff [or building health and safety person, if there is one], and if that doesn’t bring results, bring the problem to the attention of your local’s health and safety committee or your local officers.)

Are the supply and exhaust vents right next to each other?

If this is the case, the air flow can get "short-circuited," that is, the air can flow out of the supply vent and go immediately into the exhaust vent without adequately circulating in the room. If this is the case in your workroom, one of the vents needs to be moved. Usually it is easier to move the exhaust vent, since this vent often returns the air through the dead area in the false ceiling above the room. So to change its location, the building staff may only need to move the diffuser panel in the ceiling from one place to another. (The supply vent is usually fed by an air duct made of sheet-metal pipe, and so is more difficult to move.)

Are the vents blocked in any way?

If file cabinets or bookcases or just piles of paper block any of the room vents, then of course they are going to block air flow. Also partial room barriers, designed to give you some privacy, block air flow. So check out your office or workroom, remove any blockage you can and ask for help through your health and safety committee get file cabinets, etc., moved.

Are there dead spaces in your workroom or office where people regularly work?

In dead spaces air pollutants can accumulate and the air becomes stale and uncomfortable. Check for these by looking at your workplace and figuring out how air usually flows. If you feel or suspect that there is a dead area in the room, you can then get an inexpensive smoke tube, break off the tip in the suspected dead area, and see if the smoke drifts up (bad, no circulation) or moves out of the area (a positive sign of air movement). Also, if there are no flammable materials in the area, you can just light a match or a cigarette and see whether the air flows.

Are the temperature and humidity adequate?

Most government agencies and professional groups recommend that air temperatures in an office or workroom remain between 65 and 75 degrees Fahrenheit throughout the year. In plants with large open areas and in some offices, temperatures may drift below 65 degrees in the winter, and space heaters may need to be supplied. They also need to be placed away from flammable materials, so that they do not become fire hazards.

The humidity in all areas should be reasonably low, to prevent mold buildup, but high enough to avoid dry noses, headaches and susceptibility to colds and flu. Guidelines vary, but most groups recommend a range of indoor humidity of between 20 and 50 percent, or perhaps 30 to 50 percent.

It’s useful to install a wall device which measures both temperature and humidity, and to use it as a basis for getting building staff to improve indoor air quality. If you don’t get satisfaction, record room temperatures and humidity at regular times during the day, and report these to your local’s health and safety committee.

(Some of the above questions and answers have been adapted from a factsheet on indoor air quality by NYCOSH, the New York Committee for Occupational Safety and Health. For the complete factsheet and other useful weblinks, go to

(This article was originally published in two parts.)

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