Innovations in improving indoor air quality

By:

Michael J. BerensThursday, March 13, 2014

Efforts to improve indoor air quality (IAQ) have encountered some limitations as builders and engineers have had to balance them with other demands, such as improving building performance and reducing energy consumption.

A number of industry organizations, research institutions and universities throughout the world are engaged in finding solutions that will satisfy both IAQ and energy requirements. Some recent developments show promise of helping to breaking the gridlock.

Poor indoor air quality now ranks as one of the world’s most critical health issues. Studies have linked poor indoor air to a number of illnesses and diseases, including cancer and asthma, as well as to diminished performance at work and school and loss of productivity. In commercial and institutional buildings, major sources of contaminants include building materials and furnishings, and heating, ventilation and air conditioning (HVAC) components.

Although many factors can contribute to poor IAQ, there are essentially two ways to address the problem. The most effective, according to the U.S. Environmental Protection Agency (EPA), is source control. The strategy is to avoid introducing indoor pollutants by specifying only those products that reduce or eliminate emissions of harmful chemicals. This applies to a broad range of products, including flooring of all types, cleaning chemicals, furniture, printers, ceiling systems, wall coverings, paint, adhesives and sealants.

Many manufacturers have reformulated their products to be less polluting, lowering levels of volatile organic compounds (VOCs) or discontinuing the use of certain substances, like formaldehyde. The Greenguard Environmental Institute operates a certification program that maintains a list of approved products they have tested for more than 10,000 chemicals.

As a next step in source control, what if you could introduce products that helped to remove toxins from the environment? Underwriters Laboratories (UL) recently conducted two demonstration studies of paint in a Georgia middle school.

One study involved testing a prototype of a new paint specifically formulated to remove airborne VOCs from the classroom. When compared to a traditional semigloss paint and a low-VOC, semigloss paint, the VOC-reducing paint showed a meaningful reduction of airborne formaldehyde: a 45 percent reduction over the normal dissipation period of seven days, compared to a 9 percent reduction with low-VOC paint and no reduction using the traditional semigloss paint.

Even with the best source control efforts, pollutants from outdoor air, operating machinery, office or school supplies, mold and airborne viruses will infiltrate a building. These can be addressed through filtration and ventilation systems. However, the current focus on improving building performance has raised concerns about how much energy is being consumed to remove or reduce pollutants.

Two recently published studies, led by researchers at the University of Texas at Austin, provide some insight into IAQ and energy use in retail environments.

One study reviewed the results of 28 papers reporting ventilation rates and/or pollution concentrations in retail stores. It found that “meeting or exceeding the ventilation requirements does not necessarily negate the presence of pollutants above their suggested limits” and recommends “alternative control methods would be more effective, and possibly more economical, than ventilation.”

The other study investigated the impact of high-MERV filters on energy and indoor air quality. The researchers conducted field measurements of system airflow, filter and coil pressure drop, fan pressure rise and power draw on units with and without fan speed control.

They found that high-MERV filters resulted in savings during fan-only mode in constant speed units but increased energy use in other units. They observe, however, that “energy consumption increases were offset by improvement in clean-air-delivery-rate.”

Researchers in Germany and Taiwan are taking a different tack, developing new sensor technologies that control IAQ and consume less energy. The study conducted at Chang Gun University, reported in February’s issue of Medical Engineering & Physics, involved building an indoor air quality monitoring system based on wireless sensor networks (WSNs) technology. Experimental results showed a 30 percent increase in transmission speed with a 30 percent reduction in energy use.

A research consortium being coordinated at Saarland University is developing a gas sensor system for monitoring VOCs that will provide high-quality indoor air without the energy losses typically associated with ventilation. The intelligent ventilation system will automatically supply fresh air to rooms and indoor spaces as and when needed, thus reducing energy consumption levels by as much as one half. The project is being supported with funds from the European Union.

Built environments will never be totally risk-free, but continued research and development can help to minimize risk while meeting performance and sustainability requirements. In addition, as one expert has pointed out, better coordination between energy and IAQ technicians is needed to create better-integrated solutions.

About the Author

Michael J. Berens

Michael J. Berens is a freelance researcher and writer with more than 30 years of experience in association communication and management. He can be reached atmjberens@mjberensresearch.net.

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