SPONSORS

On a daily basis, the average human breathes in about 16,000 quarts of air, each containing about 70,000 visible and invisible particles that are a fraction of the size of a grain of sand. Indoors – where air can be two to five times more polluted than outdoors – people can breathe in bacteria and other microorganisms, smoke, dust, fumes and other irritants.

Poor indoor air quality (IAQ) can cause a whole host of ills – both literally and figuratively. It significantly influences the occurrence of communicable respiratory illnesses, allergy and asthma symptoms, and sick building symptoms. It also can lead to absenteeism and reduced productivity in schools and hospitals. In fact, the total costs to the U.S. economy from poor IAQ range as high as $168 billion per year.

One study of 813 “sick buildings” found that more than 75 percent of IAQ problems were related to the buildings’ heating, ventilation and air conditioning (HVAC) system. Fortunately, IAQ problems can be significantly reduced with an effective HVAC air filtration system. Air filters provide the primary defense for building occupants and HVAC equipment against pollutants generated within a building as well as pollutants from air drawn into a building from the HVAC system. And in addition to improving IAQ, effective air filtration can offer a number of other advantages to facilities pursuing “green building” status.

Sobering Statistics
Indoor air pollutants are unwelcome visitors in virtually any setting. However, they pose an even bigger problem in healthcare and educational facilities where there are large numbers of at-risk people including patients, seniors and children. Consider the effects of poor IAQ:
• 50 percent of all illnesses are either caused or aggravated by poor IAQ. (American College of Allergy, Asthma & Immunology)
• Up to 64 million U.S. office workers and teachers may be at risk of suffering from Sick Building Syndrome. (World Health Organization)
• Airborne nosocomial diseases account for four to five percent of all hospital-acquired infections. (Industry estimates)
• About 20 percent of the nation’s schools have problems linked to IAQ. (U.S. Department of Education, U.S. General Accounting Office)
• U.S. children miss more than 10 million school days each year because of asthma due to poor IAQ. (American Lung Association)
• Half of parents polled in a national survey were concerned about the quality of the air children breathe while at school, and eight out of ten said they believe a school’s poor IAQ can have a direct negative effect on a student’s academic performance and health. (Opinion Research Corporation)
• For every ten workers, poor IAQ caused an additional six sick days per year. (Environmental Protection Agency)
• Average productivity loss due to poor IAQ is between three and seven percent. (Occupational Safety and Health Administration)

Air Filters: The First Line of IAQ Defense
Good IAQ in schools, hospitals and other facilities depends on a number of factors. One of these factors is effective air filtration, which is why selecting the right HVAC filter and filter media is so critical.

The first step in determining the best type of HVAC filter needed is to identify the types and sizes of particulate pollutants in the building. Removal of all airborne contaminants is simply not practical in most facilities, so once problematic pollutants are identified, it is time to look at filter efficiency.

Filtration efficiency defines how well the filter cleans indoor air by removing airborne particles. Low-efficiency filters (in the range of 25 percent efficiency on 3-10 micron particles) are typically used to keep lint and dust from clogging the heating and cooling coils of an HVAC system. Medium- and high-efficiency filters (up to 95 percent efficiency on 3-10 micron particles) are typically used to remove mold, pollen, soot and other small particles. HEPA (High Efficiency Particulate Air) filters are used when 99.97% efficiency and above (for 0.3 micron particles) is desired.

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) has an important HVAC industry standard that addresses filter efficiency: ASHRAE 52.2-1999. The ASHRAE 52.2 Standard measures the fractional particle size efficiency (PSE) of an HVAC filter. This indicates the filter’s abil-ity to remove particles of differing sizes between 0.3 and 10 micrometers in diameter. A MERV, or Minimum Efficiency Reporting Value, is assigned to a filter based on a minimum PSE. A MERV 1 is least efficient, while a MERV 16 is most efficient. HEPA and ULPA filters have filtration efficiency that is higher than MERV 16 and are not measured by the ASHRAE 52.2-1999 test standard.

Achieving Green Building Milestones
Good IAQ is one of the main tenets of many Green Building programs, including the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) program. In fact, facilities can work towards points/credits under the LEED-EB (Existing Building) program by adopting the proper air filtration strategy.

While an effective HVAC air filtration strategy has a direct effect on IAQ, it also has an effect on another Green Building concern: energy efficiency. HVAC filters play a significant role in the energy used to operate an HVAC system: the lower the filter’s resistance to air passing through it (also known as the pressure drop of the filter), the lower the energy consumption will be. Switching to a lower pressure drop filter is one of the easiest changes for institutional facilities to make in an effort to reduce energy costs. That is because, with a lower pressure drop filter, the HVAC system motor needs to overcome less resistance to deliver the required air flow, thus reducing the motor’s energy consumption. For example, a 0.05” WG reduction in a filter’s initial pressure drop reduces energy costs by 3.5% or approximately $7 per filter, while a 0.20” WG reduction in a filter’s initial pressure drop can reduce energy costs by 10% or approximately $28 per filter. Keep in mind that a switch to a lower pressure drop filter can often be made without any sacrifice in filtration efficiency.

Here are a few additional examples of how the proper air filtration strategy has a direct effect on other green building issues:
• Greenhouse gas emissions – A 0.05” WG reduction in a filter’s initial pressure drop reduces CO2 emissions 4% or 120 lbs. per filter. A 0.20” WG reduction in a filter’s initial pressure drop can reduce CO2 emissions by 9% or 480 lbs. per filter.
• Raw material use – Some filters provide superior performance while using less media than other filters. In addition, filter media can be made with recycled polymer from manufacturing waste streams.
• Waste output – Choosing high-capacity pleated filters can extend filter life and reduce changeouts. An extended filter life can reduce waste streams while minimizing resistance to air flow.

Improved Health & Productivity
The right air filtration strategy can promote healthier indoor air while also meeting other green building needs and saving money on energy costs – answering critics’ charges that green buildings cost more.

Studies have shown that improving the indoor environment can lead to as much as a 20 percent improvement in worker productivity, for gains of $40-$250 billion per year. Superior IAQ also contributes to a favorable learning environment for students and an overall sense of comfort, health and well-being. Since, according to the Environmental Protection Agency, most Americans spend 90 percent of their time indoors, institutions would be well-served to look at the advantages of upgrading their air filtration system.

Dave Matela, CAFS, Kimberly-Clark Filtration Products. For more information on IAQ and air filtration issues visit the Resource Center at www.kcfiltration.com.