Over the past decade, there has been an increased concern with Indoor Air Quality (IAQ) in both the environmental health and safety field and general public.  Indoor air quality refers to the quality of air within public buildings and private homes.  Poor IAQ or "sick building syndrome" are terms used whenever the occupants of these areas experience adverse health effects that subside upon leaving the building.  The symptoms may include headaches, fatigue, itching burning eyes, skin irritation, nasal congestion, throat irritation, and nausea. 

Many different types of indoor pollutants have been implicated as the sources of IAQ problems including: airborne dust, bioaerosols, carbon dioxide (CO²), carbon monoxide (CO), environmental tobacco smoke, formaldehyde, ozone (O³), radon, and volatile organic compounds (VOC's).  Other environmental factors such as ambient temperature, relative humidity, noise, and ventilation, also contribute to the quality and comfort of your work environment.

Airborne Dust
Airborne dust is typically comprised of particles and fibers that harmlessly float about in our daily environments and usually are of no health and safety concern.  Under certain conditions large concentrations of airborne dust can become a nuisance or hazard to the occupants of indoor environments.

Bioaerosols
The term bioaerosol refers to both living and non-living biological air contaminants.  This can include mold or mildew (fungi), bacteria, viruses, algae, animal dander, dust mite allergens, and pollen.  These contaminants travel through the air and are often invisible.

Many IAQ problems begin as moisture problems such as leaks, floods, or excessive humidity.  These moist conditions allow organisms such as mold and mildew to grow rapidly.  These conditions can be found in many locations, such as bathrooms, damp or flooded basements, wet appliances (humidifiers and air conditioners), and some carpets and furniture. Mold, mildew and other biological contaminants can also grow in poorly maintained building ventilation systems. These systems can distribute the contaminants through the building to the occupants.

How Can I Reduce Exposure to Bioaerosols?
You can reduce your exposure to biological contaminants in several ways:

Carbon Dioxide
Carbon dioxide (CO²) is an odorless, colorless gas that is a by-product of normal human respiration.  Exhaled breath from building occupants is an important source of CO² indoors.  High CO² concentrations indoors can be an indicator of poor air circulation or underventilation.

Normal outdoor CO² concentrations are typically around 350 ppm.  An indoor concentration of greater than 1,000 parts per million (ppm) of CO² is indicative of a potential indoor air quality problem.  CO² concentrations below 1,000 ppm usually indicates that the ventilation is adequate to deal with the normal products associated with human occupancy.  However, an indoor CO² concentration less than 1,000 ppm does not always insure that there is no IAQ problem, there can be other contaminant sources contributing to poor IAQ.

Carbon Monoxide
Carbon monoxide (CO) is an odorless, colorless, gas that interferes with the body's ability to deliver oxygen to the rest of the body.  It is produced whenever there is incomplete combustion of fuels.  These fuels may be in the form of wood, charcoal, natural gas, or fuel oil.  Carbon monoxide can also be emitted from combustion engines (automobiles, gas powered lawn mowers, etc.), poorly ventilated kerosene or space heaters, furnaces, woodstoves, gas stoves, fireplaces, and tobacco smoke.

CO inhibits the distribution of oxygen in the blood to the rest of the body.  Depending on the amount inhaled the symptoms can range from fatigue, headache, weakness, confusion, disorientation, nausea, and dizziness.  Extremely high levels can cause death.  The symptoms are sometimes confused with the flu or food poisoning.  Children, elderly, and people with heart and respiratory illnesses are particularly at high risk for adverse health effects of carbon monoxide. 

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Environmental Tobacco Smoke
Research and field studies have indicated that environmental tobacco smoke (ETS) is one of the most harmful of all indoor pollutants.  Burning tobacco releases a complex mixture of particles and over 4,000 chemicals into the air. Forty-three of these chemicals are known to induce cancer in both humans and animals and many of the others can induce cancer when combined with other substances.

The best method of controlling indoor ETS is to prohibit smoking indoors.  Many public buildings have begun to implement such a policy.  The EPA and National Institute of Occupational Safety and Health (NIOSH) advise that building owners or facility managers restrict smoking and should implement smoking cessation programs.

The Columbia University Smoking Policy can be found in the Office of the Executive Vice President for Administration section of the Columbia University homepage at http://www.columbia.edu/cu/evp/smoking.html .

Formaldehyde
Formaldehyde (HCHO) is a colorless chemical with a strong pungent odor. It is classified as VOC and is an important industrial chemical used to make such things as building materials and household products.  It is found in glues, wood products, preservatives, permanent press fabrics, paper product coatings, and certain insulation materials.  Products such as particleboard, cabinets and furniture, plywood wall panels, and urea-formaldehyde insulation can off-gas formaldehyde gas.  Off gassing of formaldehyde in new buildings can come from building materials and textiles

Taking the following precautions may decrease formaldehyde exposure:

Ozone
Ozone (O³) is a colorless gas with a pungent odor.  Ozone can be generated from electrical motors, photocopy machines, and electrostatic air cleaners.  The symptoms of ozone exposure may include cough, respiratory irritation, shortness of breath, headache, fatigue, and eye irritation.  These symptoms usually subside within two to four hours of cessation of exposure. 

Keep in mind that ozone's odor can be detected well below the concentration at which symptoms would be encountered.  Indoor concentrations of ozone can be reduced through adequate ventilation and proper maintenance of electrical equipment and photocopy machines.

Radon
Radon is radioactive gas estimated to cause many thousands of cases of lung cancer each year.  Radon comes from the natural (radioactive) breakdown of uranium in soil, rocks, and water and gets into the air we breathe. Radon gas can seep into buildings such as offices, schools, and homes through cracks or other openings in the foundation.  Radon's decay products can cause lung cancer, and radon is second to smoking as a cause of lung cancer in the United States.

Due to the fact that people spend many hours of the day in their homes, the most significant chance for exposure to radon is in the home.  The Environmental Protection Agency (EPA) and the Surgeon General recommend that all homes be tested below the third floor.  The EPA also recommends that all schools be tested regularly.

Volatile Organic Compounds (VOC's)
VOC's are organic compounds that can be the source of IAQ problems when their concentrations exceed normal background levels.  Potential sources include personal care products, cleaning products, paints, lacquers, varnishes, pesticides, pressed wood products, and insulation.  Microorganisms have been shown to release VOC's which results in a moldy, musty odor. 

Indoor levels of VOC's can be kept to a minimum by selecting products that are low emitting when possible.  In addition, VOC concentrations can be diluted through effective ventilation. 

Temperature and Relative Humidity
The ambient indoor temperature and relative humidity of an indoor environment can contribute to the quality and comfort of your indoor environment.  High ambient temperatures and relative humidity can cause occupant discomfort and can provide the appropriate conditions for the growth of molds and mildews.  

The American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc. (ASHRAE) recommends that office indoor temperatures during winter months be between 69 and 76 degrees Fahrenheit (F) with a relative humidity between 30 and 60 percent.  During the summer months they recommend an indoor temperature range of 73 to 79 degrees F and a relative humidity between 40 to 60 percent.

Heating, Ventilation, and Air-Conditioning (HVAC) systems
HVAC systems are designed to provide air at comfortable temperature and humidity levels, free of indoor air contaminants.  HVAC systems that are improperly operated or maintained can contribute to poor indoor air quality.  Operating a ventilation system according to its design specifications and the performance of regular maintenance and inspections helps to reduce the chance for an indoor air quality problem.

In the ASHRAE standard 62-1989,"Ventilation for Acceptable Indoor Air Quality", it is recommended that at least 20 cubic feet per minute (CFM) of outside air be supplied to  each occupant of indoor office spaces.  These recommendations have been chosen to control carbon dioxide and other contaminants with an adequate margin of safety. 

Summary
It is important to remember that the majority of IAQ problems are relatively minor.  This means that occupants may suffer health effects similar to cold or flu-like symptoms.  In the case of the workplace it may result in lost workdays or a decrease in productivity.  Serious or permanent health effects are much rarer, however sometimes they occur. 

IAQ is a relatively new field and much of what is known about it has come about within the last 20 years.  There is a great deal of research being conducted today to find out more about IAQ problems. 

How to Schedule an IAQ Investigation
If you feel that the quality of air in your workspace is poor, you should first notify your supervisor.  If your supervisor cannot resolve the issue through area management, or other means, the EH&S office should be notified by your supervisor at (212)854-8749 (MS) or (212)305-6780 (CUMC), during normal office hours, or by sending an e-mail request to ehrs@columbia.edu (MS) or ehs-safety@columbia.edu (CUMC).

Be sure to take note of important information with regards to any health effects you experience, what time of day you experience the symptoms, odors, visible contamination, water damage, etc. to make the investigation be as thorough as possible.

View the Indoor Air Quality Investigation Policy