Indoor Air Resources

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A Healthy School Year Starts with Good IAQ

September 2015 IAR

By: Robert Martin, CAFS, Associate Category Manager  |   09.21.15

School kids will need more than a balanced lunch, plenty of exercise, and hand sanitizer to stay healthy this school year. They also need a healthy school building in which to learn, create and grow. A school’s indoor air quality (IAQ) directly impacts student academic performance and health, making IAQ improvements an important consideration for facility management and maintenance personnel. A simple air filter upgrade may be all it takes. 

Effective air filtration provides a prime defense for building occupants against pollutants generated within a building as well as pollutants from air drawn into a building from the HVAC system. Upgrading a school’s air filtration system with filters that utilize mechano-electret media may prove to be a simple and low-cost step toward improving the health of the school environment. 

How Big is the IAQ Problem in Schools?

According to the U.S. Department of Education, more than 20 percent of public schools in the U.S. report having unsatisfactory IAQ. 

Managing IAQ in schools presents unique challenges, at the center of which are issues relating to child safety and responsibility for public (taxpayer) funds. In schools, occupants are in close proximity to one another, with four times as many occupants as an office building with the same amount of floor space. As schools add space – including portable classrooms — the operation and maintenance of each new space is often different, placing added strain on HVAC systems and maintenance staff. 

Older school buildings may be at greater risk for IAQ problems. The average public school in the U.S. is more than 40 years old, and as of 2012, more than 14 million children attended class in deteriorating facilities, including those with poor air quality. 

One of the greatest IAQ health risks in children is asthma, a disease that strikes about one out of ten school-aged children. Asthma is a leading cause of school absenteeism due to a chronic condition, accounting for nearly 13 million missed school days each year. 

Poor IAQ may also put students, teachers and staff at risk for headaches, dizziness, nausea, allergy attacks, respiratory problems and sometimes life-threatening conditions such as Legionnaire’s disease and carbon monoxide poisoning. 

Not All Air Filters are Created Equal

There is an art and a science to selecting the right air filter, and facility managers would be wise to look beyond the filter’s purchase price, and even beyond its MERV (Minimum Efficiency Reporting Value) when evaluating various air filtration options to be sure they choose a filter with high-efficiency removal of respirable particles associated with poor IAQ. 

While MERV does provide a simple basis for choosing a filter, in order to better understand the filter’s in-use performance in providing for good IAQ, it’s important to evaluate the filter’s efficiency in capturing the submicron particles that can cause health and productivity problems in building occupants. 

This information is available in the filter’s full ASHRAE 52.2 test report (specifically the Fractional Particle Size vs. Particle Diameter Curve), which provides the efficiency of the filter over three particle size ranges: E1 (very fine particles in the 0.3 to1.0 micron range), E2 (fine particles in the 1.0 to3.0 micron range), and E3 (coarse particles in the 3.0 to 10.0 micron range). The E1, E2, and E3 ASHRAE 52.2 test values for a given filter provide a more complete picture of a filter’s filtration performance over the three particle size ranges. 

High E1 and E2 efficiencies are critical for providing for good IAQ and helping building occupants avoid illness due to poor IAQ. However, many pleated air filters today (especially at commonly used MERV 8) have very low E1 and E2 efficiencies. In fact, until recently under the ASHRAE 52.2 Standard, there was no minimum requirement threshold for E1 particulate capture below a MERV 14 rating and no minimum requirement threshold for E2 particulate capture below a MERV 9 rating. 

Air filters with filtration media that combines a robust mechanical structure with the added benefit of an electret charge are able to be more efficient at particle capture. The media’s mechanical efficiency provides for sustained filtration efficiency, and its electret charge increases initial efficiency and is particularly useful in increasing capture efficiency for submicron particles. 

Because a filter’s MERV rating does not necessarily indicate its ability to remove submicron E1 and E2 particles, it is possible for two similar filters of the same MERV rating (one using mechanical only media and the other using electret-treated media) to have different filtration efficiencies. For example, a MERV 8 electret-treated media filter could have better E1 particle capture than a MERV 11 mechanical-only filter. Indeed, recent testing shows that filters using electret-treated media perform on average 20 percentage points higher in E1 efficiency and 20 percentage points higher in E2 efficiency than mechanical filters on the market today. 

Better IAQ = Better Health + Better Learning

According to an EPA survey, schools with IAQ management programs have led to improved workplace satisfaction, fewer asthma attacks, fewer visits to the school nurse and lower absenteeism. Studies by researchers at Carnegie Mellon University have shown an average overall health improvement rate of 41 percent due to improved IAQ. 

With the right air filtration strategy and effective implementation, educational institutions may be able to positively impact the wellbeing and attendance record of its students and faculty without incurring additional overall expense. In situations where schools are compensated based on student attendance this could be a huge win for all. 

For more guidance about improving IAQ in your school, visit the EPA’s Tools for Schools Program.


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