Ventilation Rates and School Work Performance

Four studies in schools have investigated the linkage of ventilation rates to objectively measured, as opposed to self-reported, school work performance. A Norwegian study [22] performed in 35 classrooms located in eight schools used reaction times in a standard test to measure student concentration and vigilance. Reactions were 5.4% faster with a ventilation rate of 8.1 air changes per hour (ach) corresponding to 26 cfm per person compared to 2.6 ach (8 cfm per person). A U.S. study [23] in 5th grade classrooms from 100 schools used student performance in standard academic tests as the measure of performance. Of the 100 classrooms in the study, 87 had ventilation rates less than the 15 cfm per student minimum requirement in the ventilation standard applicable at the time of the study [24]. In these 87 classrooms, with ventilation rates between 1.9 and 15 cfm per person, the fraction of students passing the standardized math and reading tests increased linearly with ventilation rate. For each 2.1 cfm per person increase in ventilation rate, there was a 2.9% increase in the proportion of students passing the standardized math test and a 2.7 % increase in the proportion of students passing the standardized reading test. For both math and reading, statistical analyses indicated that the increases in student performance with ventilation rate were very unlikely to be the result of chance. The impacts on performance of increasing ventilation rates above 15 cfm per person were uncertain. In a Danish study performed within four classrooms [11, 12, 25], Wargocki and Wyon used performance tasks representing various aspects of schoolwork, from reading to mathematics that were embedded into the normal school work. The speed and accuracy of task performance was assessed. This study reported a statistically significant 8% increase in speed of school work tasks with a doubling of ventilation rate. There was no statistically significant influence of ventilation rate on the number of errors made by students. Figure 4 provides more detailed results from this study.

Figure 4. Student performance versus ventilation rate based on a study in Denmark [12]. Performance was based on the speed (top figure) and accuracy (bottom figure) of completing various school work tasks. The various data points represent results from multiple experiments and multiple types of work tasks. [Figure 4 reproduced with permission.]

In Japan, college student performance in classroom settings and in a laboratory setting on standardized tests was evaluated at different ventilation rates [26, 27]. In three tests implemented in the field study, one on theory and two involving memorization, performance improved 5.4%, 8.7 %, and 5.8%, respectively, with increases in ventilation rate from 0.4 to 3.5 ach (approximately 1.6 to 15 cfm per person). The laboratory study included only tests of memorization performance, and had results similar to those from the field study. However, in these studies, the ventilation rates per person at the lower air exchange rates were very low even for classrooms, e.g., less than 2 cfm per person. In addition, these studies intentionally did not disentangle the effects of ventilation and temperature. Temperatures were higher by approximately 4 °F in the low-ventilation conditions, as they would be in a building cooled by the outdoor air supply. Higher temperatures, in the temperature ranges encountered in this study, averaging 81.5 °F in the low ventilation condition, have been shown to reduce work performance [28]. Thus, these two studies do not provide information about how ventilation rates affect student performance when temperature is maintained constant, but the studies do indicate the combined effect of ventilation and temperature on school work.

Student taking a standardized test.

As discussed in the section of this web site focusing on building ventilation, higher classroom ventilation rates have also been linked to a reduction in student absence, which, in turn, may improve student learning.

In summary, while the relevant research is not extensive, the available scientific literature indicates the potential for 5% to 10% increases in aspects of student performance with increased classroom ventilation rates. Ventilation rates in roughly half of U.S. public elementary school classrooms appear to be less than specified in building codes [29-31]; thus, the opportunities for increasing student performance by increasing ventilation rates may be substantial.