Do classroom ventilation rates in California elementary schools influence standardized test scores? Results from a prospective study

Abstract

Limited evidence has associated lower ventilation rates (VRs) in schools with reduced student learning or achievement. We analyzed longitudinal data collected over two school years from 150 classrooms in 28 schools within three California school districts. We estimated daily classroom VRs from real-time indoor carbon dioxide measured by web-connected sensors. School districts provided individual-level scores on standard tests in Math and English, and classroom-level demographic data. Analyses assessing learning effects used two VR metrics: average VRs for 30 days prior to tests, and proportion of prior daily VRs above specified thresholds during the year. We estimated relationships between scores and VR metrics in multivariate models with generalized estimating equations. All school districts had median school-year VRs below the California VR standard. Most models showed some positive associations of VRs with test scores; however, estimates varied in magnitude and few 95% confidence intervals excluded the null. Combined-district models estimated statistically significant increases of 0.6 points (P = 0.01) on English tests for each 10% increase in prior 30-day VRs. Estimated increases in Math were of similar magnitude but not statistically significant. Findings suggest potential small positive associations between classroom VRs and learning.

The ventilation problem in schools: literature review

“…Table 2 includes 11 studies of the associations of student performance with ventilation rates or CO 2 concentrations. In five of these studies, reported in six papers, 13,16,17,27,41,44 students' scores on standard academic achievement tests used by school districts were employed to assess student performance. In the remaining six studies, 32,38,39,42,45,46 special tests were added by the researchers to measure student performance.…”

“…A tenth study found general improvements in performance with increased ventilation rates that were not statistically significant. 44 Performance generally improved a few percent, to as much as 15%, with increased ventilation rate or with lower CO 2 concentration. Five of eleven studies were intervention studies 32,38,39,45,46 in which ventilation rates were increased and changes in performance within students were measured.…”

“…Test scores generally improved with increased ventilation rate, but the improvements were not statistically significant. 20,44 This cross-sectional study in China studied 1414 students, age 13-14, in 30 classrooms within 10 naturally ventilated schools.…”

Significance of the School Physical Environment – A Commentary

“…Their prior study found that pass rates in math and reading tests increased 2.9% and 2.7%, respectively, per each 1 L/s per student increase in VR within the 87 of 100 classrooms that had VRs less than specified in the applicable standard. A third study from California found small increases in test scores with increased VRs that were mostly not statistically significant. Other research, including blinded controlled intervention studies, found that higher VRs are associated with improved student performance on special tests inserted into the curricula, for example tests of reading comprehension or addition.…”

Ability to Determine the Quality of Indoor Air in Classrooms without Sensors

“…In all of the works, authors claims that one of the problems is inefficient natural ventilation, which consists buoyancy-driven ventilation and ability of opening windows. Insufficient rates of fresh air supply to the classrooms are connected with inappropriate indoor air quality, occurrence of SBS symptoms among pupils [3] and weaker results in the exam pass rates [5]. Natural ventilation types are common among schools.…”