Numerous studies confirm what owners and operators of hospitals, schools, office buildings, airports and other kinds of commercial buildings have known for many years: People are healthier, more comfortable and more productive in structures with good indoor air quality.

The American Society of Heating, Refrigerating and Air Conditioning Engineers defines acceptable IAQ 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.”

Most people know that air pollution can impact their health. A recent report by the World Health Organization linked exposure to polluted air to a wide range of health problems including respiratory and cardiovascular diseases and cancer. The WHO report attributed 7 million premature deaths worldwide to air pollution exposure in 2012.

According to the U.S. Environmental Protection Agency, indoor levels of pollutants can be two to five times higher than outdoor levels. With Americans generally spending about 90 percent of their time indoors, as reported by the Centers for Disease Control and Prevention, the importance of managing IAQ is paramount. People work, eat, drink, study, recover and sleep in enclosed environments within commercial buildings where the air could be compromised.


A top problem

It is perhaps no wonder that the EPA consistently ranks indoor air pollution as one of the country’s top five environmental health risks. As a result, experts from the U.S. Occupational Safety and Health Administration said they believe that more people may ultimately be affected by indoor air pollution than outdoor air pollution.

Building designers, owners and operators are teaming up to focus on improving indoor air quality. They are collaborating with their building-industry partners, including manufacturers of heating, ventilation and air-conditioning systems, who are experts in creating solutions that simultaneously address IAQ, occupant comfort and energy efficiency.

The benefits of improving IAQ are well established:

• In schools, the EPA analyzed multiple studies and concluded that increasing the outdoor ventilation rate can improve teacher and student performance, increase test scores by as much as 15 percent and reduce the transmission of airborne infections. 

• In hospitals, the U.S. Department of Health and Human Services discovered a strong link between inside air quality and hospital-acquired infections — one of the top causes of patient deaths.

• And in office buildings, a study by Michigan State University’s School of Planning, Design and Construction found that moving from a conventional office building to one that is certified for green HVAC under the Leadership in Energy and Environmental Design program from the U.S. Green Building Council caused absenteeism from allergies and asthma to drop as much as 50 percent.


Keys to success

An effective IAQ program starts with a thorough facility audit. Audit data helps building owners and operators assess current conditions, evaluate risk, identify existing and potential problems, and develop and implement an improvement plan.

Many organizations engage an environmental engineer or IAQ consultant to help them with this process. A well-qualified, third-party expert can analyze results from IAQ tests and building assessments, and help the organization develop a plan to implement measures to improve indoor air quality. 

Some improvement measures are as simple as choosing less toxic cleaning supplies, sealing cracks in walls and openings around doors and windows, or changing traffic patterns in the parking lot so vehicles do not idle near the building’s air intakes.

However, many problems require a more thorough intervention such as advanced HVAC technologies that can enable significant IAQ improvements. For example, building automation systems can help a building operator maintain the optimum temperature, relative humidity, room air pressure, air exchanges and outdoor air ventilation for each zone in a given building.

Effectively controlling indoor conditions can restrict the growth and spread of bacteria, mold and other pathogens that can cause infections, respiratory illnesses and other health problems for building occupants.



There is no single technology solution for buildings with IAQ issues. Each building is unique and air quality may be affected by the building site, design, renovations, maintenance of the building and its mechanical systems, occupant density, activities conducted within the building, quality of air outside the building and a variety of other factors.

Maintaining indoor air quality involves one or more of these four primary methods:

Source control:Managing the sources of pollutants. This can be accomplished by identifying and removing sources of contaminants from the building and its surroundings, changing the timing of their use or isolating them from people using physical barriers or air-pressure relationships.

Local hooding/exhaust:Using local hooding and exhaust systems to remove contaminants from the air at their source. An example would be installing a canopy hood and exhaust fan over a grill in a commercial kitchen to remove smoke and cooking odors before they can be dispersed into the building’s indoor air.

Dilution:Diluting the concentration of indoor pollutants by using the ventilation system to introduce and distribute adequate amounts of fresh outdoor air to the building. An HVAC system that is well-designed, well-maintained and well-operated will dilute and remove many odors and contaminants.

Air cleaning:Using air cleaning and filtration technologies. Air cleaning removes a wide variety of contaminants of concern from both indoor and outdoor sources including particles, fumes, gases, vapors, odors, volatile organic compounds, bio-effluents, bacteria, viruses and fungi from indoor air.


Manufacturer response

Historically, it was difficult to find a single air-cleaning technology that could solve multiple indoor-air problems. Each technology tended to focus on a specific air-quality issue — particulates, for example. However, building owners and operators have demonstrated a growing need for a one-system product that helps them deal with IAQ issues without creating other risks or concerns. HVAC market manufacturers have introduced advanced systems to deal with multiple IAQ problems. These catalytic air-cleaning systems address the full range of IAQ problems that building owners and operators are likely to encounter. In addition, they are easy to install and simple to operate.

Advanced multifunction air-cleaning systems can be installed in the HVAC system air handler in both new and existing buildings of all types. Some of the more common applications of the system are in health care facilities, schools, airports and other buildings where the comfort, health and productivity of building occupants is a priority.

Regardless of the building type, understanding and addressing the needs of stakeholders and decision makers is critical for a successful IAQ technology application. Applying the correct air-cleaning product can help maintain the building design integrity and provide healthy indoor environments for building occupants and visitors throughout the structure’s life.


Brian Hafendorfer, a licensed professional engineer, is a principal applications engineer for Trane, a leading global provider of indoor comfort products and services and an Ingersoll Rand brand. In his current role, he is responsible for developing integrated HVAC products for Trane customers and providing a link between the marketing, design and manufacturing organizations. He has been with the company more than 14 years and is a member of ASHRAE.