An assessment of indoor environmental quality in schools and its association with health and performance

• T, RH, CO2, and settled dust were measured in 70 schools in Southwestern US.
• Surface cleanliness was evaluated using ATP systems and contact agar plates.
• Students' performance, attendance, and health data were obtained from the district.
• Performance was associated with both indoor T and ventilation rate.
• Health outcomes were associated with both ventilation rate and culturable bacteria.

In order to examine the associations between different indoor environmental quality (IEQ) indicators and students' performance, absenteeism and health data were collected, and sampling and monitoring were conducted in a 70 school district in the Southwestern United States during two academic years. These included measurements of temperature (T), relative humidity (RH), carbon dioxide (CO2), and settled dust. A standardized cleaning protocol was employed for surface sampling and cleaning effectiveness evaluation utilizing adenosine triphosphate (ATP) monitoring systems to detect biological contamination, and contact agar (RODAC) plates to detect culturable bacteria. In addition, student data related to socioeconomic background, absenteeism, performance, and number of visits to school nurse was retrieved anonymously from the school district. Significant associations were observed between percentages of students scoring satisfactory in mathematics and reading tests and both indoor T (r = −.353 and r = −.311 respectively) and ventilation rate (r = .417 and r = .479 respectively), which was estimated based on CO2 levels. In addition, ventilation rate was associated with mean number of visits to school nurse due to respiratory symptoms, and culturable bacteria with mean number of visits due to gastrointestinal symptoms; but there were no significant correlations between absenteeism and IEQ parameters in these school-level analyses. In conclusion, classroom ventilation rate, temperature, and hygiene of high contact surfaces appear to be important IEQ parameters, potentially related to student health and/or performance.