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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.

Understanding Canada’s Carbon Reporting Requirements

  • Writer: Ava Montini
    Ava Montini
  • Jan 7
  • 5 min read

Updated: Jan 28

Canadian companies required to report their carbon emissions face an increasing need to balance compliance with sustainability leadership. For larger businesses and public companies, carbon reporting is no longer about following regulations. It’s about meeting stakeholder expectations, addressing environmental challenges, and securing a competitive advantage in a rapidly evolving market.

Navigating Canada’s carbon reporting requirements might seem overwhelming, especially with the layers of federal, provincial, and international frameworks. But these challenges also bring opportunities—to improve operational efficiency, identify cost-saving measures, and build trust with investors and customers.


This guide aims to break down the complexities and provide actionable insights to help businesses comply while aligning with broader sustainability goals.


Why Carbon Reporting Matters

Carbon reporting has become a cornerstone of corporate accountability and a critical tool for mitigating climate change. In today’s market, stakeholders demand transparency regarding environmental impacts, which directly influences investor confidence, customer loyalty, and employee engagement. Public companies in Canada often find their carbon disclosure tied to financial performance metrics, and failure to comply can impact access to capital or even lead to penalties.


Beyond immediate compliance, carbon reporting reflects a company’s commitment to sustainability. By aligning business practices with Canada’s net-zero ambitions for 2050, companies can reduce their environmental footprint while positioning themselves as industry leaders.


The risk of inaction can be significant: businesses that fail to prioritize emissions reporting and reduction may face regulatory fines, reputational harm, and missed opportunities for innovation.


Overview of Canada’s Carbon Reporting Framework


Federal Regulations

Canada’s federal government has implemented comprehensive reporting programs to standardize emissions tracking and accountability. One of the cornerstone programs is the Greenhouse Gas Reporting Program (GHGRP). Managed by Environment and Climate Change Canada (ECCC), this program mandates facilities emitting 10,000 tonnes or more of greenhouse gases (GHGs) annually to submit detailed emissions data. For those emitting over 50,000 tonnes, third-party verification becomes a mandatory requirement, adding another layer of rigour to the reporting process.


The Canadian Net-Zero Emissions Accountability Act sets the national stage by establishing legally binding targets to achieve net-zero emissions by 2050. While primarily focused on government accountability, the Act’s associated policies filter down to businesses through funding programs, technology incentives, and strategic initiatives that encourage industries to adopt cleaner practices.

Another critical component is carbon pricing and offsets. The federal Output-Based Pricing System (OBPS) applies to large industrial emitters, requiring them to track emissions and offset excesses through credits or direct reductions. Companies need to report accurately and integrate these calculations into their financial strategies, as carbon pricing directly impacts operational costs.


Provincial and Territorial Regulations

Provincial and territorial governments add another layer of complexity. Regulations vary by region, reflecting local priorities and emissions profiles:


  • Ontario has introduced the Emissions Performance Standards (EPS), which require facilities emitting 10,000 tonnes or more of GHGs annually to report and adhere to sector-specific benchmarks. This system provides flexibility but also demands meticulous emissions tracking.

  • British Columbia focuses on public accountability through its Climate Change Accountability Act. While primarily targeting public-sector organizations, it offers guidelines for businesses interested in voluntary reporting, creating an environment of proactive sustainability.

  • Quebec operates a cap-and-trade system, one of North America’s most robust. Businesses emitting over 25,000 tonnes of GHGs annually are required to participate, submitting emissions data to ensure compliance with allocated caps and trading allowances as needed.


For businesses operating across provinces, this mosaic of regulations underscores the importance of tailored, region-specific reporting strategies.


International Reporting Standards

Canadian companies with global operations or international investors may also need to align with widely recognized frameworks like the Task Force on Climate-related Financial Disclosures (TCFD) and the Global Reporting Initiative (GRI). These frameworks emphasize the integration of climate-related risks into financial disclosures, offering guidance on best practices for reporting Scope 1, Scope 2, and Scope 3 emissions. Adhering to these standards can enhance credibility with international stakeholders and ensure readiness for emerging global regulations.


Key Steps for Compliance


1. Understand Your Obligations

Compliance begins with a thorough assessment of applicable reporting requirements. Start by identifying which federal, provincial, and international frameworks apply to your operations. This will depend on factors such as your industry, geographic footprint, and annual emissions levels. Companies operating in multiple provinces must account for variations in regional regulations and ensure that their reporting systems can handle these complexities.


2. Implement Robust Data Collection Systems

Accurate data collection is the foundation of effective carbon reporting. Businesses should invest in systems capable of tracking emissions across all scopes:


  • Scope 1 emissions cover direct emissions from owned or controlled sources, such as fuel combustion in company vehicles or manufacturing processes.

  • Scope 2 emissions refer to indirect emissions from purchased electricity, steam, heating, or cooling.

  • Scope 3 emissions include all other indirect emissions across the value chain, such as supplier activities, employee commuting, and waste disposal.


Learn more about Scope 1, 2, 3 Emissions here


Advanced software solutions can automate data collection, reducing human error and improving reporting accuracy. For larger organizations, integrating emissions tracking into existing enterprise resource planning (ERP) systems can streamline operations and ensure consistency across departments.


3. Seek Third-Party Verification

Third-party verification is not just a regulatory requirement for some businesses; it’s also a critical trust-building tool. Independent audits lend credibility to your emissions data, reassuring investors and regulators that your disclosures are accurate and reliable. Verification partners, such as Bureau Veritas, SGS, and DNV, specialize in conducting thorough audits and providing certification for environmental compliance. These organizations often go beyond basic verification, offering insights into data gaps and areas for improvement, helping companies refine their reporting processes and maintain long-term accuracy.


4. Develop an Emissions Reduction Strategy

Carbon reporting is most impactful when paired with an actionable emissions reduction strategy. Use your emissions data to identify key areas for improvement, such as energy efficiency upgrades, renewable energy adoption, or supply chain optimization. For companies subject to carbon pricing, reductions can also translate into direct cost savings by lowering compliance obligations.


5. Stay Informed on Policy Changes

Canada’s regulatory landscape is constantly evolving to meet climate goals. Regularly review updates from Environment and Climate Change Canada, as well as provincial and territorial authorities. Engaging with industry associations can also provide early insights into upcoming policy shifts, ensuring that your organization remains ahead of the curve.


Benefits Beyond Compliance

Committing to robust carbon reporting and reduction offers far-reaching benefits. Transparent emissions disclosures can attract sustainability-focused investors who are increasingly scrutinizing ESG (Environmental, Social, Governance) metrics. Operationally, emissions tracking often highlights inefficiencies, leading to cost savings and streamlined processes. Furthermore, by taking a proactive stance on sustainability, companies enhance their brand reputation, fostering loyalty among environmentally conscious consumers and employees alike.


Resources for Canadian Businesses

Navigating carbon reporting can be challenging, but there are numerous resources available to support businesses:


  • Environment and Climate Change Canada’s GHGRP Portal: A comprehensive guide to federal reporting requirements. Visit Here

  • Canada’s Climate Action Incentive Fund: Financial support for businesses investing in emissions reductions. Visit Here

  • Task Force on Climate-related Financial Disclosures (TCFD): A globally recognized framework for climate-related disclosures. Visit Here



Canada’s carbon reporting requirements represent a vital step toward addressing climate change and fostering a more sustainable future. For businesses, compliance is an opportunity to demonstrate leadership, drive operational improvements, and build stakeholder trust. By adopting detailed and transparent carbon reporting practices, companies can position themselves as change-makers in the transition to a net-zero economy.

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.

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