Classroom Air Quality - Engineering & Natural Sciences

Study shows classroom air quality affects student performance

A study conducted by researchers from TU’s Indoor Air Program shows maintaining adequate ventilation and thermal comfort in classrooms could have direct impacts on student learning and performance.

Appearing Aug. 28, 2015, in the scientific journal PLOS ONE, the groundbreaking research with international implications is unlike any other published to date, examining the combined effect of classroom ventilation and temperature on academic performance. Findings at a large school district in the southwestern United States reveal proper classroom ventilation and temperature could raise students’ average test scores above state standards.

classroomThe study found fifth-grade students’ math scores (average 2,286 points) increased along with increasing ventilation. The estimated score increase was 74 points from the lowest observed ventilation value (0.9 liters per second/person) to the recommended minimum ventilation rate (7.1 l/s per second/person). An additional 64-point increase was reported along with decreasing temperature, ranging from the highest observed temperature of 78oF (25oC) to the lowest observed 67oF (20oC). Effects of similar magnitude were observed for reading and science scores.

The test score data were based on an annual statewide assessment of learning designed to relate levels of test performance to the expectations defined in state-mandated curriculum standards. For all subject areas, the state used a scale score of 2100 points for met standard and 2400 for commended performance (above state passing standards). Data on classroom conditions were based on measurements conducted in 140 fifth-grade classrooms of 70 schools by TU’s Indoor Air Program during the winter and spring months preceding the learning assessment.

“Adequate ventilation involves a prescribed amount of outdoor air being introduced into the classroom, with the intent to dilute and replenish stale air in the room with incoming fresh (outdoor) air,” said Richard Shaughnessy, director of TU’s Indoor Air Program. “The right amount of air exchange for a classroom depends on the number of students as well as building characteristics. In addition, in highly polluted urban areas, supply air should be filtered to prevent exposure to outdoor air pollution.”

Ventilation rates fail to meet the recommended levels in majority of schools
The American Society of Heating, Refrigerating and Air-Conditioning recommends a minimum ventilation rate of 7.1 l/s per person in classrooms. TU’s study found ventilation rates below the recommended level in 96 percent of the classrooms measured. Similar findings have been reported elsewhere in the United States as well as in many other countries.

“Studies from different countries worldwide indicate that ventilation and thermal comfort are compromised in a large proportion of schools,” said co-author Ulla Haverinen-Shaughnessy, who also has conducted similar research in Europe. “Previous studies have suggested that inadequate ventilation and thermal comfort could cause decreased decision-making performance or symptoms such as headache, difficulty concentrating or fatigue, which could explain the lower test scores.”

Beginning of school year is a good time to check HVAC operation and make necessary adjustments
The study’s authors note whereas heating, ventilation and air conditioning (HVAC) are responsible for a large part of school buildings’ operational costs as well as their carbon footprint, schools should strive for optimal HVAC operation without compromising the demand for adequate provision of supply air. The effects on students’ health and academic achievement must be taken into consideration in this process.

To view the study “Effects of classroom ventilation rate and temperature on students’ test scores” in PLOS ONEclick here.

For more information, please contact:
Richard Shaughnessy
Director, TU Indoor Air Program