Research Articles

Rethinking Heat in Thousands of School Classrooms Through Continuous Monitoring and Novel Exposure Metrics

This paper characterized heat exposure in over 3,500 classrooms through novel heat metrics, and showed how temperature can vary within school buildings, with and without air conditioning. Led by Pilar Botana Martinez at Boston University School of Public Health,  with Boston Public Schools and Boston University collaborators. 

M. Pilar Botana Martinez, Priam Vyas, Katherine H. Walsh, Lauren Main, Lauren Bolton, Yirong Yuan, Masanao Yajima, M. Patricia Fabian. Indoor Environments Journal. September 2025. https://doi.org/10.1016/j.indenv.2025.100105

Decision Tools for Schools Using Continuous Indoor Air Quality Monitors: A Case Study of CO2 in Boston Public Schools

In collaboration with Boston Public Schools staff, our team analyzed 245 million minute-level CO2 measurements recorded during the 2022-2023 school year from 3,659 classrooms in 125 school buildings. We found that CO2 levels varied 10x within and between schools, reflecting high variability in classroom characteristics like ventilation and occupancy. Schools with central mechanical ventilation generally had lower and more stable CO2 concentrations compared to schools with natural ventilation, but elevated levels were still recorded in all schools. We developed data quality control protocols and demonstrated the utility of academic-school partnerships for supporting interventions and investments.

Beverly Ge, Koen Tieskens, Priam Vyas, M. Pilar Botana Martinez, Yirong Yuan, Katherine H. Walsh, Lauren Main, Lauren Bolton, Masanao Yajima, M. Patricia Fabian. The Lancet Regional Health - Americas. August 2025. https://doi.org/10.1016/j.lana.2025.101148

Estimating Air Exchange Rates in Thousands of Elementary School Classrooms Using Commercial CO2 Sensors and Machine Learning 

This paper analyzed data from 3206 sensors across 125 schools in a large urban school district in the Northeastern United States using a cost-effective and scalable air exchange rate (AER) model. The method assumes well-mixed conditions and replicates the tracer gas technique, leveraging statistical machine learning and knowledge of classroom operations to automate AER calculations at the end of occupied periods and identified 648,956 CO2 decay curves over one school year.

Yirong Yuan, Masanao Yajima, Jihno Lee, Katherine H. Walsh, Brenden Tong, Lauren Main, Lauren Bolton, M. Patricia Fabian. Indoor Environments Journal. June 2025. https://doi.org/10.1016/j.indenv.2025.100083 

Research Brief

Toward Healthier Air in Schools: The State of Indoor Air Quality Programs in K-12 Schools in the U.S. & Findings to Guide Action

This report characterized the indoor air quality (IAQ) monitoring and related policies across K-12 schools across the United States. A total of 23 K-12 schools were analyzed to inform key themes and to highlight existing and needed resources to tackle IAQ in K-12 schools. 

Kyleigh Gunn, M. Pilar Botana Martinez, M.Patricia Fabian, Muskaan J. Khemani, Rebecca Pearl Martinez, Joseph Pendleton, CHESS team. 

Research Brief