School District-Wide Renovations, Indoor Environmental Quality, and Illness Absence

This peer-reviewed research article presents a longitudinal study evaluating the impact of district-wide school renovations on illness-related student absenteeism. Conducted in a Mountain West school district that undertook a $600 million bond program to renovate 45 schools between 2016 and 2021, the study analyzed pre- and post-renovation data covering 1,217 school days and 45,428 students across seven school years.

The renovations focused primarily on upgrading heating, ventilation, and air conditioning (HVAC) systems, along with improvements to surface cleaning protocols. The study measured indoor environmental quality (IEQ) parameters including ventilation rate, temperature, relative humidity, absolute humidity, and surface biocontamination (via ATP measurements). Illness-specific absence data—categorized by respiratory illness (RI) and gastrointestinal illness (GI)—were drawn from district records.

Key findings include:

• post-renovation absences due to respiratory illness were significantly lower;
• more than one-third of RI and GI absences could be reduced by upgrading school facilities and adhering to recommended ventilation standards;
• increased cleaning frequency reduced GI-related absences; and
• maintaining higher absolute humidity and cooler indoor temperatures was associated with fewer illness absences.

Higher ventilation rates and lower surface biocontamination were independently associated with fewer illness-specific absences. The study draws on a natural experiment design, with continuous IEQ monitoring before and after renovations providing superior statistical power compared to prior cross-sectional studies.

Findings are useful for school facility managers, policymakers, and public health practitioners seeking evidence-based guidance on school renovation priorities and indoor environmental quality standards.