When the U.S. Environmental Protection Agency (EPA) published its seminal report to Congress on Indoor Air Quality (IAQ) in 1989, the HVAC industry raced to provide products and services that would help improve the quality of the air in homes and businesses alike. Almost overnight, the public became concerned with ventilation, filtration, and humidity control issues, and contractors and manufacturers scrambled to find solutions to the sometimes complex problems associated with IAQ.
Since then, associations, such as ASHRAE, and individual states, including California and New Jersey, have put forward standards and regulations that address IAQ issues, but the definition of IAQ still remains somewhat nebulous. Perhaps that is because so many factors affect IAQ — everything from poor ventilation and high (or low) humidity to pesticides, mold, and radon. In addition, it can be a challenge to quantify proper IAQ, particularly when occupants in a space have varying tolerances to different contaminants and irritants.
The EPA defines IAQ rather vaguely, calling it “a term referring to the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants.”
ASHRAE, on the other hand, gets more specific, defining it as “air in which there are no known contaminants at harmful concentrations as determined by cognizant authorities and with which a substantial majority [80 percent or more] of the people exposed do not express dissatisfaction.” These definitions are seemingly poles apart, but, in the end, does it really matter? Absolutely. As long as there is not a standard definition, business owners will not be able to compare apples to apples. At the very least, they should be able to make an informed decision about their options and have a basis for making that decision. If HVAC contractors only provide filtration, then how can they address concentrations of airborne germs and volatile organic compounds [VOCs]? If contractors only offer a source of fresh air, how can they keep the coil clean and avoid ‘dirty sock syndrome?’ It won’t make a difference how much you ventilate — you will never achieve true, pure IAQ.
The best way to achieve IAQ, defined as air that is fresh, clean, and pure, he notes, is through fresh air ventilation (dilution), filtration of particulates, UVC germicidal purification, and VOC reduction with photocatalytic oxidation (PCO) or comparable technology. Consistent, year-round air quality requires a control to cycle the air on a schedule and ensure the air in the facility is fresh, clean, and pure — even during shoulder months when not heating or cooling.
IAQ consists of the conditions that make up the indoor environment of a building, including temperature, humidity, purity, and freshness. However, even within a facility, those conditions may be perceived differently by occupants.
While some IAQ issues impact health, others only impact comfort or only harm some individuals. A facility may be filled with pollen and dander, but if no one in the building is allergic to those things, they likely wouldn’t consider it to have an IAQ problem. But, if the building is occupied by someone with allergies or asthma, those same conditions could negatively impact health as well as comfort, thus leading the residents to rate their IAQ as very low.
IAQ should also not be confused with Indoor Environmental Quality (IEQ), which includes any building condition that negatively impacts human health and well–being. This could include everything from discomfort caused by inadequate lighting to lack of protection from sustained noises to poor ergonomic conditions that lead to individual stress or injury.
IEQ is usually addressed by Leadership in Energy and Environmental Design [LEED] and green-building qualifications. While IAQ is a major component of IEQ, it takes specialized contractors to holistically address IEQ concerns.
Jeffrey May, principal scientist, May Indoor Air Investigations LLC, Tyngsborough, Massachusetts, and author of the book, “My House Is Killing Me!,” believes the definition of IAQ comes down to fresh air and good filtration, but only if the HVAC systems have been properly maintained in the first place.
“I believe the HVAC industry is responsible for the health of the country, because all the air that anyone breathes in a building goes through a mechanical system,” he said. “If that system isn’t maintained properly, then there are going to be issues. The biggest source of IAQ problems, in my experience, is contaminated heating and cooling equipment.”
Air conditioning systems are often the bigger problem, noted May, as the combination of condensate and dust results in microbial growth on the coil and in the drain pan. “The only way to prevent dust in the mechanical system is with good filtration. Most people sell filters by saying they will reduce the number of particles in the air, and that’s important, but that’s not really the purpose of the filter, at least not in terms of air quality. You have to protect the air conditioning coil, the pan, and all that fibrous lining from accumulating any kind of dust, otherwise the system becomes contaminated, and the resulting mold and bacteria will be blown all over the building.”