The first half of 2000 has been a public relations nightmare for the air duct cleaning industry. Negative stories have appeared in the press nationwide. While the direct impact on the duct cleaning industry is hard to assess, articles warning consumers against cleaning ducts can't be good for business.

In March, in conjunction with the American Academy of Allergy, Asthma and Immunology (AAAAI) Annual Meeting, the association put out a press release reporting on a study by Amy Tsay of Indoor Biotechnologies. "Cleaning ducts has no significant improvement on allergic symptoms," concludes the Charlottesville, Va., researcher. The AAAAI press release was picked up by Reuters and hit the mainstream press on March 6. The story made its way into national and local newspapers, as well as the internet on sites like www.HealthCentral.com.

Two months later another damaging article appeared in U.S. News and World Report. The May 8, 2000 issue's cover story was titled "The Allergy Explosion and What You Can Do About It." Within the feature article, a two-page sidebar gave advice on steps to eliminate potential allergy and asthma triggers in the home. "Don't bother cleaning your air ducts," advised the magazine. It cited a University of Cincinnati researcher who warned, "People see what's in the ducts and say, 'Oh, that's what I've been breathing in.' The answer is no. That's what's been sitting in your air ducts."

Researchers, government officials and those in the IAQ field have been asking whether air duct cleaning provides a health benefit for years. While studies have been performed to demonstrate the effectiveness of cleaning procedures for removing contaminants from within systems, no scientific evidence exists to support the claims by some cleaners that cleaning ducts improves health. In fact, a recent ASHRAE study points out the potential dangers to the indoor environment that duct cleaning may pose to occupants.

Duct Cleaning: A Review of Associated Health Effects and Results of Company and Expert Surveys appeared earlier this year in ASHRAE Transactions 2000. University of Minnesota researcher Lisa M. Brosseau and her colleagues assessed the hazards faced by cleaning personnel and occupants in cases of non-routine duct cleaning. Their findings are based on a thorough literature review, and surveys of duct cleaning firms and others in the IAQ field.

The ASHRAE study points out several areas where occupant exposure to contaminants could arise during and after duct cleaning. Both manual and mechanical cleaning procedures offer the possibility of introducing aerosolized dust and fungal spores into the indoor breathing zone. The use of anti-microbial agents and dust sealants is cited as a possible source of chemical exposure. The study points out that while these hazards are readily identified by industry and engineering controls may exist to negate them, "there is much less agreement about how to clean the systems." The implication is that some cleaners may not take sufficient safeguards to prevent occupants, or workers, from contamination by allergens and materials found in HVAC systems.

Industry Response

IE Connections interviewed three influential business owners in the HVAC system cleaning field to get their reactions to the recent onslaught of negative press about their industry. Their responses shed important insights into the subject and point out some facts that the researchers haven't addressed.

"We have helped thousands of allergy and asthma sufferers," says Tom Yacobellis, President of DUCTBUSTERS, an HVAC system cleaning franchise organization with more than 20 locations world-wide. "These people have personally filled out testimonial forms and sent them to our company locations throughout the country. The messages are so positive that they keep us motivated despite the tremendous amount of negativity directed toward our industry from outside. Not every client claims to feel better, but the result of our work on behalf of allergy and asthma sufferers often ranges from mild to massive relief.

Yacobellis stresses that while his company's customers with allergies usually note improvements to their conditions after cleaning, the type of cleaning performed by his franchisees is superior to that performed by many independent operators. "DUCTBUSTERS only provides a total system cleaning, and that's after a full system inspection and assessment. We don't just clean ducts. Air handlers, coils and every other part of the system is addressed, and we also repair damaged internal insulation, Yacobellis told IE Connections.

Many others in the HVAC system field tell anecdotes of clients who experience dramatic reductions in allergy or asthma symptoms after duct cleaning. Huey Miller Jr. owns ServiceMaster IAQ and also serves as president of the Mechanical Systems Hygiene Institute (MSHI), a division of the non-profit Association of Specialists in Cleaning and Restoration (ASCR International). He told IE Connections about an influential public servant in his community whose allergy symptoms virtually disappeared after ServiceMaster IAQ cleaned, sanitized and coated her HVAC system, repaired air leaks, and installed pleated media filters in place of cheap disposables. "She has become our best salesperson, always telling how much she appreciated what we did and how much better she feels," said Miller.

The fact that emerging scientific evidence appears to conflict with anecdotal evidence is not lost to Bob Baker, CEO of BBJ Environmental Solutions, a manufacturer of antimicrobials, disinfectants and odor removal products.

"We should practice restraint and carefully explain that much of our information comes through long and repeated personal experiences and not scientific research," cautions Baker. He says that much of the criticism of the duct cleaning industry is a result of confusing observations and experiences - what he calls "stories" - with objective data. At the same time, he does not discount the importance of anecdotal evidence. "Stories have their place. Many of the advances of modern medicine started as observations and stories that led to solid research and new proofs," says Baker.

The indoor environment is a difficult setting to study because so many factors contribute to air quality. In that context, it is important for researchers to qualify the information they put forward. In the AAAI study, the researcher measured dust mite allergens and cat allergens. The study did not address fungi at all. Nonetheless, after the Reuters press release the story drew headlines like Air duct cleaning unnecessary for preventing allergies. But what about allergies to mold?

"Moisture and mold are the most common problems associated with HVAC systems, yet the AAAI study did not address them at all, said Yacobellis. He worries that studying a small segment of contaminants can lead to incomplete conclusions. That sentiment was echoed by the National Air Duct Cleaners Association (NADCA) in response to the AAAI report.

In a position statement released at the Healthy Indoor Environments conference in May, NADCA argues that, "the conditions observed by those [AAAAI] researchers were limited to a small sample of homes in a single geographic region," and that, "researchers may have been guided by a limited definition of 'air duct cleaning,'" that did not include cleaning of fans, coils and other HVAC mechanical components.

Like its members, NADCA falls back on the perceptions of duct cleaning customers in defense of its position that HVAC system cleaning may rid the indoor environment of one potential allergy and asthma trigger source. In response to the question of whether air duct cleaning can alleviate allergy symptoms, NADCA says for its members the answer "can be found in the comments of thousands of satisfied customers."