06/07/2013 03:13 pm ET Updated Jun 07, 2013

School Ventilation Study Finds Classroom Air Quality May Be Contributing To Student Illness


California classrooms may need a big, healthy breath of fresh air.

According to a recent study conducted by Lawrence Berkeley National Laboratory and published in the journal Indoor Air, the majority of California elementary school classrooms lack proper ventilation, which likely contributes to higher rates of illness among students.

"More kids get sick and stay home from school. Districts get less revenue, and families shoulder more child care expenses," the study's lead author Mark Mendell explained to the Sacramento Bee. "That's the implication of all this...It's a correlation, and it suggests a causation."

The two-year study looked at 162 classrooms in three school districts, each one representing a different climatological portion of the state--from the temperate, foggy San Francisco Bay Area to sunny southern coast to the warm, dry Central Valley. In each of the classrooms studied, researchers installed a carbon dioxide monitor to determine the room's ventilation rate and compared data from those devices to the students' records of illness-related absences.

They found that the median ventilation rate of the classrooms in all three school districts was below the minimum level required by the state of California. In the Central Valley district, where classrooms relied heavily on air conditioning and kept the majority of outside-facing widows closed, the ventilation in 95 percent of all classrooms was below the minimum standard.

There was also, in some cases, a statistically significant correlation between ventilation rates and the number of days students in a given classroom were out sick. The study estimated that, just by bringing ventilation rates up to the state's minimum standard, California schools could cut their rate of illness-related absences by 3.4 percent.

Since a portion of school funding is linked to student attendance, the authors noted that getting better ventilation and thereby decreasing absences could bring in an additional $33 million to schools every year, while only costing about $4 million to make all the necessary improvements.

The specific schools investigated were not identified in the report.

In a separate analysis, the team noted a relationship between classroom ventilation and students' standardized test scores--with higher ventilation during the 30 days prior to the test being associated with higher English scores and poor ventilation over the course of the entire school year often coming with decreased math scores. However, the researchers cautioned against reading too much in their findings regarding test scores. "Overall, these findings are not completely consistent and are difficult to interpret," they wrote.

"Our overall findings suggest that, if you increased ventilation rates of classrooms up to the state standard, or even above it, you would get net benefits to schools, to families, to everybody, at very low cost," Mendell said in a statement. "It's really a win-win situation."



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