In the modern classroom, the focus is often on technology, curriculum, and engagement. However, a critical element that directly impacts student health and learning often goes overlooked: the air they breathe. In many schools, especially older buildings, ventilation systems are inadequate or non-existent. This can lead to a buildup of pollutants and, most critically, an increased risk of airborne infections.

The importance of good air quality cannot be overstated. A well-ventilated space keeps the concentration of airborne particles at bay, including viruses and bacteria. When traditional ventilation falls short, supplementary solutions become essential. This is where air purifiers, both commercial and do-it-yourself (DIY), offer a viable and often more affordable solution.

Airflow Simulations and Infectious Particles

To effectively combat the spread of infectious particles in a classroom, we simulated various scenarios to determine the optimal placement and effectiveness of air purification systems. Our findings indicate that a room with no ventilation or filtration systems is a catastrophic scenario, leading to a significant buildup of harmful airborne particles. Note: Warm, human-emitted aerosol rises toward the ceiling.

Introducing four portable filtration solutions, one in each corner of the classroom, yielded promising results, as it effectively lowered the concentration of infectious particles. However, the classroom equipped with only a ventilation system fared worse, showing a 1.5 times higher concentration of infectious particles compared to the room with the four portable units. Interestingly, in this ventilation-only scenario, a decrease in humidity from 50% to 40% had a negligible impact on particle concentration, suggesting that humidity control alone is not a sufficient mitigation strategy.

The most effective solution we modeled was the combination of the existing ventilation system with a single, strategically placed portable filtration unit. This setup not only kept infectious particle concentrations low but also maintained low levels of CO2, indicating good overall air quality. A final simulation explored the effectiveness of just one portable filtration unit without the aid of a ventilation system. While this proved to be a viable solution for reducing particle concentration, its effectiveness was heavily dependent on its placement within the room. The placement of a single unit presents a challenge, as it is often unknown who might be an infectious source in the classroom. Therefore, placing the purifier next to an infected individual, while seemingly logical, is not always the most effective strategy for broader particle capture and overall air purification.

Understanding Airflow: More Than Just a Breeze

Airflow within a room is a complex dance of pressure, temperature, and particle movement. It’s not as simple as opening a window and hoping for the best.

As seen in previous simulations, airflow can be unpredictable, creating pockets of stagnant air and unexpected currents. This complexity is why simply relying on natural ventilation is often insufficient. Air purifiers work by actively drawing in air, filtering it, and releasing clean air back into the room, creating a controlled, clean-air environment that disrupts the spread of contaminants.

The Economic Solution

One of the biggest hurdles to improving school infrastructure is often cost. Upgrading a building’s HVAC system to meet optimal air quality standards can be an enormous and often prohibitive expense. This is where air purifiers shine as a cost-effective alternative.

DIY solutions, like the one proposed by Safe Air Schools and the Corsi-Rosenthal box, can be constructed for a fraction of the cost of a commercial unit. These simple but effective devices use common materials to create a powerful air filtration system. For those with a larger budget, commercial units offer advanced features and certified performance. The key is that these portable solutions can be deployed where they are needed most, providing a targeted approach to improving air quality without the massive capital investment of a full system overhaul.

Ultimately, investing in cleaner classroom air isn’t just a matter of health; it’s an investment in a more productive and resilient learning environment. By embracing both DIY and commercial air purifiers, schools can overcome economic barriers and provide students and teachers with the quality air they deserve.

Further research is needed, incorporating parameters like temperature and relative humidity levels, to accurately simulate conditions throughout the entire year.