If one had to slap a label on the 1990s, one could argue for titling it, “The Decade of Refrigerant Chaos — and Change.” Another option: “The Decade of Indoor Air Quality.”

An overstatement? Not at all.

While air conditioning has now been around for decades, the concerns over deteriorating indoor air and overall indoor environmental quality hit the mainstream head-on in the 90s.

One could argue that the Arab oil embargo of the 1970s changed building construction forever in America. Homes and commercial buildings were better insulated as a result, with tighter construction, closer-fitting windows, and less outside air infiltration — all designed to save energy. At the time, it did not appear to be a bad idea.

However, with this type of tight construction, buildings became prone to increased problems due to inadequate ventilation, growth of mold, an increase in particulates, etc.

It took a few years for the problems to accumulate and present themselves to the point where they were given the catchall term: indoor air quality (or, IAQ). With it came Sick Building Syndrome.


In 1980, requests to evaluate indoor office environments made up only 8% of investigations made by the National Institute for Occupational Safety and Health (NIOSH). By 1992, that figure had grown to 75%.

In a 1992 conference paper, attorney Lawrence S. Kirsch described the IAQ state-of-affairs this way to members of the International Facility Manage-ment Association (IFMA): “After years of relative obscurity, the subject of indoor air pollution has now gripped the attention of the media and the public. The press and television often report on alleged ‘sick building’ episodes in which various individuals in a single building experience symptoms, such as coughing, head-aches, respiratory irritation, dizziness, or nausea that appear on entering the building and disappear on leaving.”

Lawsuits regarding Sick Building Syndrome were few and far between prior to 1990. However, that began to change after 1993 when a federal judge awarded five employees of the U.S. Environmental Protection Agency (EPA) compensation for health-related problems encountered from working in a federal facility in Washington, DC. That decision prompted the Building Owners and Managers Assoc-iation (BOMA) vice president of government and industry affairs to proclaim: “The floodgates have opened.”

In truth, the “poster child” for sick buildings was found in Polk County, FL, where a new courthouse building opened to almost immediate complaints from workers. They experienced headaches, nausea, and fatigue. Many of the workers had to be relocated and, eventually, the courthouse was practically reconstructed at a cost of $35 million — greater than its original construction cost.

While research is inconclusive, according to the EPA, “In the last several years, a growing body of scientific evidence has indicated that the air within homes and other buildings can be more seriously polluted than the outdoor air in even the largest and most industrialized cities.”


But not all was gloom and doom in the 90s. The rise of problems brought with it a number of solutions in the last decade. Many new products surfaced, some designed to “clear the air” — electrostatic air cleaners, media air cleaners, ultraviolet lamps for in-duct use, antimicrobial coatings, coil cleaners, etc.

Throughout the issues of The News in the 1990s, it was often pointed out that regular air filter changeout and use of a good-quality air filter are two essentials to improving IAQ — along with a new diligence for building maintenance, including the care and operation of existing hvac equipment.

An entire industry based on cleaning air ducts also hit stride in the 90s. The National Air Duct Cleaners Association (NADCA) held its first convention in 1989 and a certification program for air duct cleaners was launched soon thereafter in the early 90s. (For more on the development of NADCA, see page 105.)

The EPA eventually issued a report on duct cleaning because it received so many questions from consumers. EPA’s conclusion? Not all black and white. A good duct cleaning may freshen the air in your home, but don’t expect miracles.

It also warned of contractors who used this service as a ploy to point out “dangerous flaws” involving existing equipment, trying to convince the homeowner to buy something they didn’t really need.

According to the report, “EPA does not recommend that air ducts be cleaned except on an as-needed basis because of the continuing uncertainty about the benefits of duct cleaning under most circumstances.”


In the final analysis, air filtration came into its own in the 90s and surfaced as a key component of IAQ. Filters today range in efficiencies from economy-priced, low-end filters, designed mainly to protect the hvac equipment, to high-efficiency particulate arrest-ance (HEPA) filters, designed to remove submicron particulates. Because IAQ was stressed in the 90s and today, more and more installers and end-users are upgrading from low-cost, low-efficiency filters to higher-end, more-efficient filters, sometimes using pre-filters as well.

ASHRAE Standard 52.2 evolved in the last decade. This standard put a more meaningful performance rating on filters through the use of a minimum effectiveness reporting value (MERV). This was a more accurate system to rate filters that were often advertised as “high efficiency” with little to substantiate that claim.

According to Robert Courture, president of the National Air Filtration Association (NAFA), “For years, filtration experts have called for a standard that, like those used for HEPA filters, measured the least-effective performance of a filter on a certain size particle. Much of this was predicated on the fact that mechanical or ‘media style’ filters are, ironically, at their least efficient when clean or just installed. As the dirt pack builds up through various filtration processes, the filter actually increases in efficiency.”

Electrostatic charges for filters also emerged, along with electronic air cleaners, to better clean the indoor air. The charged media attract airborne dust particles for better capture ability than untreated filters. Antimicrobial coatings and sprays also emerged as byproducts of enhanced filtration, designed to kill bacteria and fungi that are captured by the filter. (ASHRAE, in turn, has funded Research Project 909-RP to determine the efficacy of antimicrobial treatments of fibrous air filters.)

As always, contractors play a crucial role in how air filtration impacts IAQ. Improper installation, with gaps in the filter holder, or inattention to changeout schedules, can negate the best filtration strategies.

Bas is the author of two books, Indoor Air Quality: A Guide for Facility Managers and Indoor Air Quality in the Building Environment. As a staff writer for The News in the 90s, Bas authored numerous articles on IAQ. He is currently editor and publisher of Snips magazine. He can be reached at 248-244-6476.

Sidebar: Guides Available

In the late 90s, the National Air Filtration Association (NAFA) published two guides designed to help contractors understand air filtration: “The NAFQA Guide to Air Filtration” and “The Installation and Maintenance of Air Filtration Systems.”

To order copies, call 202-628-5328.

Publication date: 04/30/2001