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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

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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. PNASNature


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:

  1. Dilute what’s in the room (ventilation/outdoor air)

  2. Remove what’s in the room (filtration/air cleaning)

  3. 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+1Environmental 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.

Revolutionizing Buildings in 2024: Trends Transforming Indoor Spaces

  • Writer: Ava Montini
    Ava Montini
  • Dec 5, 2024
  • 5 min read

Buildings today are where we live, work, and connect—and they need to do more than just function. In 2024, the focus was on making them efficient, adaptable, and aligned with modern demands like sustainability and occupant health.


For facility managers and building professionals, the challenge is clear: how to improve energy use, meet regulations, and enhance tenant satisfaction—all while staying within budget. Here’s a look at the trends shaping the future of buildings and the technologies driving smarter, healthier, and more resilient spaces.



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Sustainability as the Cornerstone of Modern Buildings

Buildings account for approximately 37% of global energy and process-related CO₂ emissions and 34% of global energy demand, underscoring the critical need for sustainable solutions in the built environment. This demand has driven the development and adoption of technologies that address both environmental impact and operational efficiency.


One such area of innovation is low-pressure air filtration systems. These systems are designed to enhance indoor air quality—a critical factor for occupant health—while also minimizing the energy demands of HVAC systems. By reducing the resistance to airflow (known as pressure drop), these advanced filtration technologies can lower energy consumption and contribute to sustainability certifications such as LEED and WELL, which emphasize energy efficiency and healthier indoor spaces.


Traditional HVAC systems, while effective at meeting basic performance needs, often require significant energy input to maintain baseline standards. In comparison, modern sustainable technologies provide a more efficient, cost-effective approach without sacrificing performance. For facility managers, this means an opportunity to align building operations with environmental goals, improve the well-being of occupants, and meet evolving regulatory requirements—all while managing long-term operational costs more effectively.




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Smarter Spaces Through Technology

The smart building market is projected to grow from USD 72.6 billion in 2021 to USD 121.6 billion by 2026, driven by the adoption of IoT, AI, and predictive analytics. These technologies are transforming buildings from static structures into responsive ecosystems. For instance, IoT-enabled sensors can monitor air quality in real time, triggering ventilation adjustments to maintain optimal conditions. Predictive analytics allows facility managers to identify and address inefficiencies before they become costly problems, saving both time and resources.


Unlike older systems that rely on periodic manual checks, smart buildings integrate real-time monitoring with adaptive systems, enabling a more proactive approach. Facilities that implement IoT-based predictive maintenance can achieve significant cost savings and operational improvements. According to McKinsey & Company, such approaches can reduce maintenance costs by up to 25%, decrease unplanned outages by up to 50%, and extend the operational life of machinery.


These benefits stem from the ability to monitor equipment health in real time, predict failures before they occur, and schedule maintenance activities more effectively. By leveraging IoT and analytics, organizations not only enhance operational efficiency but also improve tenant satisfaction through increased reliability and reduced downtime.



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Wellness-Driven Design

As research continues to reveal the profound impact of indoor air quality (IAQ) on health, wellness-focused design has become a priority. Studies from Harvard T.H. Chan School of Public Health have demonstrated that indoor air quality (IAQ) significantly affects cognitive function. The Global CogFx study, involving 302 office workers across six countries, found that improved IAQ led to better cognitive performance. Additionally, Americans spend approximately 90% of their time indoors, where pollutant levels can be 2 to 5 times higher than outdoor levels. In response, facility managers are investing in biophilic design, thermal comfort enhancements, and advanced filtration systems to create healthier indoor environments.


A shining example of wellness-focused design can be seen in modern office buildings that integrate natural elements and prioritize occupant well-being. Biophilic design—incorporating features like green walls, indoor gardens, and natural lighting—has been shown to reduce stress and boost productivity among employees. Coupled with improved ventilation and thermal comfort systems, these spaces create an environment where occupants feel more energized and connected. One case study found that wellness-certified buildings saw higher employee retention rates and a measurable increase in work satisfaction, emphasizing the value of designing with health and well-being at the forefront. These principles don’t just benefit the occupants—they also enhance the long-term value of the building, making it more attractive to tenants and investors alike.


Preparing for Uncertainty

The past decade has underscored the need for resilience in building systems, particularly in the face of challenges like wildfires, extreme weather events, and fluctuating energy demands. For example, during heatwaves or cold snaps, energy grids are often strained, and buildings with adaptive energy systems—such as smart energy storage or dynamic load management—can maintain functionality while reducing their reliance on peak energy. These systems help ensure consistent performance even when external conditions push infrastructure to its limits.


Proactive strategies like integrating renewable energy sources or implementing predictive energy management also allow buildings to anticipate and mitigate potential disruptions. These approaches not only reduce energy costs but also contribute to a more stable and sustainable grid. As energy resilience becomes increasingly critical, buildings capable of adapting to these demands play a key role in ensuring reliability and sustainability for the broader community.


Data-Driven Operations

Real-time data is transforming building management, offering facility managers tools to optimize energy usage, extend the lifespan of equipment, and enhance overall tenant satisfaction. By integrating predictive maintenance programs, facilities can leverage embedded sensors to monitor equipment performance, identify inefficiencies, and trigger alerts before failures occur. This proactive approach significantly reduces costly repairs and unplanned downtime. Implementing predictive maintenance can reduce maintenance costs by 18% to 25% while increasing asset availability by 5% to 15%, underscoring its role in improving both operational reliability and cost efficiency.


Unlike traditional methods that rely on reactive repairs after a problem arises, data-driven operations provide actionable insights that enable facility managers to anticipate issues before they escalate. This not only improves system performance but also enhances tenant comfort by ensuring seamless building functionality. As more facilities adopt analytics-driven strategies, they unlock measurable benefits, including reduced operational costs, improved system reliability, and higher tenant satisfaction—all essential for maintaining competitive, high-performing spaces in an increasingly dynamic market.



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Tenant and Occupant Expectations Evolving

Post-pandemic, expectations for indoor spaces have shifted dramatically. Occupants now demand more than basic functionality—they seek healthier environments, visible sustainability initiatives, and seamless integration of technology that enhances their experience. Facility managers are rising to the challenge by implementing systems that prioritize transparency and well-being. Features like real-time building data and energy-saving dashboards optimize building operations while providing occupants with accessible, actionable insights that build trust and foster loyalty.


This emphasis on occupant-centric upgrades marks a significant departure from traditional facility management, which often prioritized operational efficiency over user experience. By addressing these evolving demands, modern buildings are not only improving tenant satisfaction but also driving higher retention rates and stronger relationships. Tangible improvements—like cleaner air, energy-efficient systems, and clear communication of these efforts—are becoming the new standard for successful facilities, setting them apart in a competitive market.



As 2024 concludes, the built environment is undergoing a profound transformation. Facility managers are no longer just maintaining buildings—they’re shaping them into spaces that align with the needs of people, businesses, and the planet. The trends driving these changes—from sustainable technologies to smart systems and wellness-focused designs—offer immense opportunities for those ready to adapt.

Explore expert insights, stay up to date with industry events, and gain a deeper understanding of the cutting-edge developments that are revolutionizing the indoor air quality landscape within Blade Air's comprehensive Insights Hub.

You can also subscribe to our monthly newsletter below for exclusive early access to Blade's Insights content, uncovering tomorrow's air quality advancements before they hit our Hub.

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