Indoor air quality (IAQ) in classrooms has a direct impact on the health, attendance, and academic performance of students and school staff. The U.S. Environmental Protection Agency (EPA) has indicated that indoor pollutant levels can be two to five times higher than outdoor levels, and in extreme cases, up to 100 times greater. This issue is particularly concerning in school environments, where children, with developing respiratory systems, are especially vulnerable to air pollution effects.
Main indoor air pollutants in schools
Schools harbor various pollutants that can accumulate indoors:
- Carbon Dioxide (CO₂): Considered a key indicator of ventilation quality. Elevated CO₂ levels can lead to drowsiness, fatigue, and reduced concentration, which impacts students’ academic performance.
- Particulate Matter (PM2.5 and PM10): These particles, generated from external sources like traffic and internal sources, can penetrate the lungs and exacerbate respiratory conditions like asthma, which is a leading cause of school absenteeism.
- Volatile Organic Compounds (VOCs): Chemicals emitted by materials such as cleaning products and furniture. Exposure to VOCs can cause headaches, respiratory irritation, and may negatively impact cognitive development.
- Biological agents: Mold, bacteria, and other microorganisms can proliferate in areas with high humidity or poor ventilation, triggering allergies and respiratory issues.
Impact on academic performance and long-term health
Studies by the Center for Green Schools and Lawrence Berkeley National Laboratory have demonstrated a direct relationship between air quality and academic performance. In well-ventilated classrooms, students achieve higher scores in math and reading, as clean air improves concentration and reduces mental fatigue.
In the long term, exposure to pollutants such as particulate matter and VOCs can predispose students to chronic respiratory diseases like asthma, resulting in higher healthcare costs, school absenteeism, and potentially lower productivity in the future.
Inequalities in school IAQ and infrastructure challenges
One of the greatest challenges in improving IAQ in schools is the disparity in resources and infrastructure among institutions. Many schools, particularly those in low-income areas, lack modern ventilation systems and the necessary funds to implement effective air purification solutions. For instance, in Vermont, the American Rescue Plan (ARP) grant program provided $15 million to improve school ventilation systems, but this amount is insufficient to address the needs of all schools.
The Center for Green Schools found that schools in urban areas often have access to federal funding and guidelines, whereas rural schools rely on state guidelines, creating a significant gap in classroom air quality.

Case studies and examples of improvement
- GBG_A2CC Project in Barcelona: Known as “Climate Refuge,” this project has implemented innovative solutions to improve IAQ in schools by using sensors and purifiers in classrooms. Data collected before and after intervention showed a 25% reduction in PM2.5 concentrations and a decrease in students’ respiratory symptoms.
- Boston Initiatives: Thanks to ESSER program funding, Boston schools installed over 4,400 IAQ sensors in 125 schools. These sensors detected ventilation issues and enabled real-time adjustments to reduce CO₂ and particle levels, thus improving IAQ and student well-being.
IAQ in the context of the COVID-19 pandemic
The COVID-19 pandemic highlighted the importance of IAQ in indoor spaces and accelerated the implementation of ventilation measures in schools. Since 2021, many schools in the U.S. and Europe have followed recommendations from ASHRAE and the WHO, suggesting a minimum of five air changes per hour in occupied spaces. However, ventilation systems in older buildings are not always equipped to meet these standards, leading to increased use of HEPA purifiers and monitoring sensors.
A 2022 report from the Center for Green Schools, backed by ASHRAE, revealed that over 25% of school districts surveyed have no plans to implement additional ventilation or air purification improvements, underscoring an urgent need for greater investment and technical support.
Incorporating advanced solutions like AQSENSOR and Dust Free can be transformative in ensuring optimal IAQ in classrooms. AQSENSOR provides real-time monitoring, allowing school administrators to maintain air quality levels safely and efficiently, while Dust Free offers powerful air purification with HEPA filtration and ionization, effectively eliminating airborne particles and VOCs. Together, these tools create a comprehensive approach that supports a healthier learning environment, reducing respiratory risks and improving concentration, attendance, and overall student well-being. For schools committed to fostering a clean and productive atmosphere, AQSENSOR and Dust Free are invaluable investments in both student health and academic success.
Stay tuned for the second part of this post, where we’ll dive deeper into international IAQ standards, case studies, and innovative projects that are making classrooms healthier places to learn and grow.
References:
- U.S. Environmental Protection Agency (EPA) – “Indoor Air Quality Tools for Schools” program offering non-mandatory but widely implemented guidelines for IAQ improvements in schools.
- ASHRAE Standards – Standards 62.1 and 241 for ventilation and infection control, recommending air changes for optimal indoor environments.
- Center for Green Schools – Studies connecting IAQ with academic performance and identifying resource gaps impacting ventilation quality.
- HealthVent Project (EU) – Guidelines aligning ventilation with WHO standards for safe indoor air quality.
- REHVA (EU) – Technical guidelines on ventilation for educational buildings in Europe, emphasizing CO₂ limits.
- Lawrence Berkeley National Laboratory – Research on the impact of IAQ on student health, focusing on schools across the U.S.