Indoor Air Quality in Schools Is Necessary
A healthy school environment contributes to a better learning environment.
It is a well-known fact that the environment affects
human performance, both physically and mentally. This is
especially true for our children, who are impacted by the
quality of air in their learning environment. School officials
are encouraged to invest a portion of their ESSER funds in
improving classroom indoor air quality (IAQ).
The School IAQ Problem
In the 1970s, the increasing cost of energy required to operate
buildings—including schools—became a concern. One solution
was to make buildings “tighter” and reduce ventilation, lowering
the energy usage needed to heat and cool the building.
However, more tightly constructed buildings and reduced ventilation
led to mold, increased VOCs (Volatile Organic Compounds)
and CO2 (carbon dioxide) levels, as well as building
occupant health issues. The term Sick Building Syndrome originated,
leading to indoor air quality concerns.
In addition, HVAC systems in schools vary greatly by
equipment type as well as age. Over the past 30 years, the
focus has been on improving IAQ as well as conserving energy.
However, at times, these focus items have conflicted with each
other, resulting in poor IAQ at the expense of reducing energy.
The School IAQ Solution
Improving air filtration is one way to improve indoor air in
schools. Replacing lower efficiency filters with higher efficiency
filters in existing HVAC systems to capture very small respiratory
droplets and virus particles may help. However, an
obstacle to increasing filter efficiency is that many commercial
HVAC systems cannot deliver the increased airflow needed to
compensate for the higher resistance (pressure drop) that higher
efficiency filters cause. Another filtration solution is to install
additional recirculation HEPA (High Efficiency Particulate Air)
filter units in classroom spaces.
Either or both filter solutions are good, but they still solve
only one part of improving IAQ. The second and more important
part of improving IAQ is the removal of airborne particulates,
such as VOC gaseous pollutants and CO2. Without the
proper amount of oxygen-rich air in schools, students become
tired and lethargic.
The solution to this second (and more important) issue of
improving IAQ in schools is adequate ventilation of the space by introducing a sufficient amount of oxygen-rich, conditioned,
outdoor air into the classrooms and exhausting the stale, spent,
oxygen-depleted air. This also reduces harmful levels of VOCs.
It is the oxygen-rich and conditioned (that is, heated, cooled,
humidified, dehumidified and filtered) outdoor air that will
assist in improving student learning ability.
The amount of outdoor airflow brought into a building,
room or indoor space is the ventilation rate per unit time,
typically expressed in cubic feet of air per minute (cfm). For
K-12 schools, the ASHRAE 62.1 regulation code stipulates
the minimum outdoor ventilation rate is 10-20 cfm of fresh
outdoor air per student.
The fact that increased ventilation rates improve both students’
ability to learn and teachers’ ability to teach was confirmed
in a 2016 Harvard study entitled “Associations of Cognitive
Function Scores with Carbon Dioxide, Ventilation, and Volatile
Organic Compound Exposures.” This research study revealed that
lower indoor CO2 levels resulting from greater amounts of outdoor
(ventilation) air raised cognitive scores between 61% and 101%.
The increase in cognitive scores was achieved by increasing the
ventilation rate of outdoor air from 20 cfm to 40 cfm per person.
Another 2021 investigation by Ty Newell, Ph.D., PE,
Emeritus Professor of Mechanical Engineering at the University
of Illinois entitled “Indoor SARS-CoVid-2 Herd Immunity and
Infection Probability Estimates Based on Ventilation, Vaccinations,
Infections and Face Masks” echoes the findings of the
2016 Harvard study and makes the following recommendations:
- Control fresh air ventilation (to maintain 800 ppm of CO2),
equivalent to doubling current building ventilation standards
from 20 cfm per person to 40 cfm per person.
- Recirculate indoor air through high efficiency filters (MERV-13 or better) with a combination of whole building air
recirculation and room space filtration systems. Recirculation
airflow levels should be similar to fresh air ventilation levels.
Finally, in June 2020, the U.S. Government Accountability
Office published a report (GAO-20-494) entitled “K-12 Education:
School Districts Frequently Identified Multiple Building
Systems Needing Updates or Replacements.” Of the school
districts surveyed, the findings of this report stated:
- About half of districts needed to update or replace multiple
systems like HVAC or plumbing.
- An estimated one-third of schools needed HVAC system
updates.
- An estimated 41% of districts need to update or replace
heating, ventilation, and air conditioning (HVAC) systems
in at least half of their schools, representing about 36,000
schools nationwide needing HVAC updates.
Reputable HVAC manufacturers and their representatives
can assist and offer recommendations to improve school indoor
air quality.
This article originally appeared in the Fall 2021 issue of Spaces4Learning.
About the Author
Anthony Rossi is a retired Greenheck technical sales and marketing executive with over 40 years of experience in the HVAC industry. Greenheck is a manufacturer of air movement, control and conditioning equipment to improve indoor air.