Indoor Air Resources

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Spring Into Allergy Season

April 3 full blog page image

By: Rob Martin, Associate Category Manager, Kimberly-Clark Partnership Products  |   04.03.14

Allergies affect 20 percent of the U.S. population and are the sixth leading cause of chronic disease. With the right air filtration strategy, your building’s HVAC system can capture airborne allergen particles to help keep occupants breathing easier.

Part of the job of a building’s HVAC system should be to eliminate or significantly reduce respiratory illness triggers that occur within the building, such as microorganisms, dust and allergens. The key is effective air filtration.


When indoor air is not filtered effectively, poor indoor air quality (IAQ) can result. Poor IAQ has been linked not only to seasonal allergies, but also to an increased risk for other respiratory problems, headaches, dizziness, and nausea.


The Air We Breathe

What is in this indoor air? Bits of particulate matter, some of which is 100 times smaller than the diameter of a human hair. These tiny particles are breathed into the respiratory system, where they can either stick to the sides of the airway or travel deeper into the lungs. The very smallest and most toxic particles – those under 2.5 microns – are most likely to travel to the deepest part of the lungs, where they can cause a variety of respiratory health problems. 

Get Rid of Allergens

Not all air filters are capable of capturing the smallest particles than can cause allergy symptoms and other illnesses. Here are some tips to help you get the most from your HVAC air filters. 

  • Look beyond a filter’s MERV. Don’t just base your selection on the filter’s Minimum Efficiency Reporting Value. The ASHRAE 52.2 Test Standard provides the efficiency of the filter over three particle size ranges: E1 (very fine particles in the 0.3 to 1.0 micron range), E2 (fine particles in the 1.0 to 3.0 micron range), and E3 (coarse particles in the 3.0 to 10.0 micron range). High E1 and E2 efficiencies are critical for good IAQ.
  • Consider electret-treated filters. Filters with filtration media that provides a good balance of mechanical and electret efficiency will almost always outperform filters the rely solely on mechanical efficiency. The electrostatic effects created in a mechano-electret media filter are particularly useful in increasing the capture efficiency for submicron particles.
  • Pay special attention to filter installation in the HVAC unit. The goal is to avoid any gaps between the filter frame and the unit, which can lead to air bypass. Bypass is significantly detrimental to IAQ. Even high efficiency filters designed to prevent health problems associated with fine airborne particles may fail to perform as intended due to bypass.


Keep in mind that many filters on the market today have low E1 and E2 efficiencies. In fact, under ASHRAE 52.2, filters in the MERV 1-12 range aren’t even measured for E1 efficiencies, and filters in the MERV 1-8 range aren’t measured for E2 efficiencies. It is therefore possible to have a MERV 8 mechano-electret media filter with better E1 particle capture than a MERV 11 mechanical-only filter.


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