Flu Season Meets School Season: How Smarter Air Quality Keeps Classrooms Healthy

Every fall, classrooms fill with students—and viruses. Discover how smarter air quality strategies like low-resistance filtration, ventilation, and HEPA keep schools healthier, reduce absences, and support better learning outcomes.

Ava Montini

Aug 19, 2025

Written by

Published on

The scene every September

Every September, the school bell rings and hallways come alive again. But as backpacks and lunch boxes make their way back into classrooms, another unwelcome guest tends to sneak in too: flu season.

Teachers know it all too well. The cough that spreads from desk to desk, the hand sanitizer bottles running low by mid-morning, the spike in absenteeism that leaves lesson plans hanging. Parents know it when the inevitable call from the school office comes: “Your child has a fever, please come pick them up.”

It’s a cycle we’ve come to accept as part of the school year. But what if healthier air could help change that story?

Why flu season and school season collide

Respiratory viruses (including influenza) spread more readily indoors, where exhaled particles accumulate. That’s not speculative; CDC/NIOSH is unambiguous that better indoor ventilation reduces occupants’ overall exposure to airborne viruses. CDC

We also know influenza isn’t only about big droplets from a sneeze. People exhale infectious virus in fine aerosols during normal breathing and speaking, which can linger and travel within a room. That was demonstrated in a landmark study that detected infectious influenza virus in exhaled breath from symptomatic adults, no cough required. PNAS Nature

The drier, colder air from the fall and winter cause low humidity, helping influenza survive and transmit more efficiently. Put simply: when we bring students back into dry, tightly sealed buildings, small airborne particles build up and stay infectious longer. That’s the fixable part.

Think of clean classroom air as a budget with three line items:

Dilute what’s in the room (ventilation/outdoor air)
Remove what’s in the room (filtration/air cleaning)
Disable what’s in the room (UVGI where appropriate)

The key is using them together, sized to the space, and tuned to the school day.

What the standards now say and why it matters

Before the pandemic, most schools designed ventilation systems mainly for comfort—things like controlling odours or keeping CO₂ levels down—not for stopping the spread of illness.

That changed with ASHRAE’s new Standard 241, which focuses specifically on infection control. ASHRAE’s Standard 241: Control of Infectious Aerosols changes the target by introducing Equivalent Clean Airflow (ECA)—a flexible, additive way to hit a per-person clean air goal using any combination of ventilation, filtration, and proven air cleaning. That means a classroom can meet its target by mixing outdoor air with high-efficiency filters, HEPA units, and/or UVGI, rather than relying on outdoor air alone. ASHRAE+1

In parallel, CDC/NIOSH and EPA emphasize practical steps for schools: keep systems maintained, upgrade to MERV-13 or better where equipment allows, and supplement with portable HEPA when central systems can’t carry the whole load. CDC+1 Environmental Protection Agency

The evidence that this keeps kids in class

In a study of 162 California elementary school classrooms, illness-related absences dropped by 1.6% for every extra 1 l/s‑person of ventilation. Increasing ventilation to meet the state standard (7.1 l/s‑person) from the average (4 l/s‑person) could reduce absences by 3.4%, gain $33 million annually in attendance-based funding, while costing just $4 million more in energy.
A study across Washington and Idaho found that a 1,000 ppm increase in indoor CO₂ correlated with a 0.5–0.9% drop in average daily attendance, translating into a 10–20% rise in student absences.
In controlled environments, each 500 ppm rise in CO₂ resulted in 1.4–1.8% slower response times, along with a 2.1–2.4% lower throughput on cognitive tasks.
Harvard’s COGfx study revealed that building occupants in green-certified, well-ventilated environments scored, on average, 101% higher in cognitive tests than those in conventional buildings.

“Will MERV-13 break my units?” (The energy/airflow reality)

The honest answer: it depends on the filter you pick and your fan capacity. Research on rooftop units shows that moving from MERV-8 to MERV-13/14 can raise cooling-mode energy use by a few percent if the filter adds a lot of resistance, or it can reduce airflow if the fan can’t keep up. That’s why filter selection matters as much as efficiency.

Not all MERV-13 filters are created equal. Traditional pleated designs often create a higher pressure drop, forcing HVAC systems to work harder and sometimes leading to performance issues. But newer filtration technologies (explicitly engineered for low resistance at high efficiency, like Blade Air's Pro Filter,) are changing that equation. By combining advanced media with optimized form factors, these filters deliver MERV-13 (and higher) performance without the heavy airflow penalty.

California’s Title 24 research reinforces this point: Many modern low-pressure MERV-13 options can maintain pressure drops under 0.20 in. w.c., keeping systems within safe operating ranges. That means schools can improve air quality, meet public health guidance, and stay compliant without sacrificing system efficiency or longevity.

When you factor in the bigger picture—fewer student absences, better cognitive performance, and improved overall school operations—the ROI clearly tilts toward upgrading. Healthier air doesn’t just protect occupants; it protects the bottom line.

How this translates into a classroom target (the ECA idea)

ASHRAE 241’s Equivalent Clean Airflow lets you add up all the ways you’re cleaning air—outdoor air, central filtration, HEPA, UVGI—until you reach the per-occupant target for your space type. It’s flexible, measurable, and avoids unrealistic demands for 100% outdoor air in cold snaps. ASHRAE

A practical approach:

Estimate your current outdoor air (from design or testing).
Add the “clean air” from MERV-13 upgrades (using published efficiencies) and from each HEPA unit’s clean air delivery rate.
If the sum doesn’t meet the ECA target, add another portable unit or rethink your filtration strategy. ASHRAE

What about measurement and transparency?

CO₂ for ventilation

Track a few representative rooms across grade levels and building wings. Persistently high readings during class point to areas needing a fix (dampers, schedules, or supplemental air cleaning). Health Canada’s 1000 ppm residential benchmark is a useful anchor for conversations with families and staff. Canada.ca

PM₂.₅ for smoke days

A couple of low-drift sensors at kid-height in hallways or problem rooms can confirm your filtration strategy keeps indoor levels below outdoors during wildfire events. Health Canada and EPA both recommend this principle. Canada.ca

Bottom line

Flu season doesn’t have to mean higher absence rates and strained HVAC systems. The most effective path is a consistent program: keep ventilation tuned, use filters that balance efficiency with low resistance, and supplement with portable HEPA or UVGI where it makes sense.

The Future of Senior Living: Trends in Air Quality and Resident Care

Jennifer Crowley
Jul 2, 2024
3 min read

Updated: Jul 8, 2024

Senior patient waving at the incoming nurse bringing him lunch in his room — Research has shown that poor indoor air quality can lead to a range of health issues, particularly for seniors who are more vulnerable to respiratory conditions.

The landscape of senior living is continuously evolving, with new trends and innovations shaping the future of resident care. One critical area of focus is indoor air quality (IAQ), which plays a significant role in maintaining resident health and well-being. In this blog, we’ll explore emerging trends in air quality management and how they are transforming senior living facilities.

The Growing Importance of IAQ

Research has shown that poor indoor air quality can lead to a range of health issues, particularly for seniors who are more vulnerable to respiratory conditions. According to the World Health Organization (WHO), indoor air pollution is responsible for about 4.3 million deaths annually. As a result, senior living facilities are increasingly prioritizing IAQ to enhance resident health, safety, and comfort.

Emerging Trends in Air Quality Management

1. Smart Air Quality Monitoring Systems

Man's hand holding an air quality monitor in his hand as a maintenance worker puts his tools away in his toolbox in the background — Facilities using smart monitoring systems report a 30% reduction in IAQ-related complaints.

These systems use advanced sensors to continuously monitor IAQ and provide real-time data and alerts. According to Harvard T.H. Chan School of Public Health, facilities using smart monitoring systems report a 30% reduction in IAQ-related complaints.

By offering real-time insights, these systems enable proactive management of air quality, ensuring that immediate action can be taken to address any issues that arise. This proactive approach helps maintain a healthier indoor environment, reduces the risk of health problems associated with poor air quality, and enhances the overall comfort and satisfaction of building occupants.

2. UV-C Light Technology

UV-C technology can reduce airborne bacteria and viruses by up to 99%, as highlighted by the Centers for Disease Control and Prevention (CDC). This technology utilizes UV-C light to sanitize the air by effectively killing airborne pathogens, including viruses and bacteria. By doing so, it significantly reduces the risk of infections, thereby improving overall indoor air quality (IAQ).

The use of UV-C light is particularly beneficial in common areas and healthcare settings where the concentration of people and the potential for pathogen spread are higher. This advanced method of air purification is essential for maintaining a healthy environment, preventing the spread of infectious diseases, and ensuring the well-being of occupants, making it particularly useful in common areas and healthcare settings.

3. Integrated HVAC Systems with Advanced Filtration

Modern HVAC systems that are equipped with high-efficiency particulate air (HEPA) filters and air exchange capabilities ensure a constant supply of clean air, which enhances resident comfort and health. According to the Environmental Protection Agency (EPA), integrated HVAC systems can improve Indoor Air Quality (IAQ) by 80% compared to standard systems.

These advanced systems are designed to effectively filter out airborne particles, including dust, pollen, and other pollutants, while also ensuring proper ventilation and air circulation. This not only reduces the presence of contaminants but also creates a more comfortable and healthier environment for residents, making them particularly beneficial in settings where air quality is paramount.

4. Green Building Materials

Physical renovation inspiration mood board containing eco-friedly building materials like stone, bamboo, hemp wood and stone — Low-emission material use reduces pollutant introduction and creates a healthier environment.

Facilities using green building materials report a 50% reduction in indoor pollutants, according to the California Air Resources Board. Green building materials are eco-friendly and sustainable construction materials designed to minimize the environmental impact of buildings.

These materials are selected based on attributes such as renewability, recyclability, low emissions, energy efficiency, durability, and resource efficiency. They are made from rapidly renewable resources like bamboo or cork, can be recycled at the end of their lifecycle, and produce minimal volatile organic compounds (VOCs) and other pollutants, improving indoor air quality.

Additionally, green building materials contribute to energy savings through their production process or use in construction and have a long lifespan, reducing the need for frequent replacements and repairs. Examples include reclaimed wood, recycled metal, low-VOC paints, and energy-efficient insulation, all of which help create more sustainable, energy-efficient, and healthier buildings for occupants.

Using low-emission materials for construction and renovation reduces the introduction of pollutants and creates a healthier indoor environment from the ground up, promoting long-term resident health.

Best Practices for Implementing IAQ Innovations

Young male maintenance employee making his rounds inspecting building ventilation — Regular maintenance of HVAC systems and air purifiers is essential for optimal performance.

Regular Training: Ensure staff are trained on the latest IAQ technologies and best practices.
Continuous Monitoring: Use smart monitoring systems to keep track of IAQ and identify potential issues early.
Maintenance: Regular maintenance of HVAC systems and air purifiers is essential for optimal performance.
Feedback Loop: Engage residents and staff in providing feedback on IAQ improvements and make adjustments as needed.

The future of senior living is being shaped by innovative trends in air quality management. By staying ahead of these trends and adopting cutting-edge technologies, senior living facilities can create healthier, safer, and more comfortable environments for their residents.

Investing in IAQ is not only a regulatory necessity but also a commitment to enhancing the quality of life for seniors. Visit us at bladeair.com for more insights and/or to investigate our innovative IAQ solutions.

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