CDC cleaner air

CDC Guidelines: The Importance of Air Exchange for Health Safety

Understanding the CDC’s Role

As America’s frontline defense in public health protection, the Center for Disease Control and Prevention (CDC) is the nations’s leading public health institution. T he CDC’s mission encompasses everything from disease prevention to public health guidance. Their expertise spans multiple areas, including:

  • Monitoring and responding to disease outbreaks both domestically and globally
  • Conducting cutting-edge scientific research on health hazards and diseases
  • Providing evidence-based recommendations to healthcare providers and the public
  • Developing programs to promote healthy behaviors and prevent illness
  • Collecting and analyzing crucial health data to inform policy decisions

The CDC’s Stance on Air Quality

Among their many public health recommendations, the CDC places significant emphasis on air quality management, particularly in preventing respiratory illness transmission. Their guidance centers on one crucial metric: air exchanges per hour (ACH).

The 5 ACH Minimum Standard

The CDC recommends maintaining a minimum of five air exchanges per hour (5 ACH) in occupied spaces. But what does this mean for you?

If you’re a homeowner, the CDC suggests a simple yet effective strategy: switch your thermostat fan setting from “auto” to “on.” This small change ensures continuous air circulation, even when your heating or cooling system isn’t actively running. Additionally:

  • Regular filter replacement is essential for maintaining optimal air quality
  • Proper maintenance of your HVAC system helps ensure efficient air exchange
  • Consider upgrading to high-efficiency filters when possible

The Role of Outside Air

Both residential and commercial spaces benefit from proper ventilation with outside air. This serves two critical functions:

  1. Providing necessary oxygen for occupants
  2. Diluting indoor air contaminants

Advanced Air Treatment Options

While proper ventilation is fundamental, the CDC acknowledges that additional air treatment technologies can enhance indoor air quality:

  • Ultraviolet Technology: The CDC specifically mentions UV treatment as a passive air quality improvement method
  • Advanced Active Technologies: Beyond UV, newer technologies can actively target airborne pathogens and surface contaminants
  • Filtration Systems: High-efficiency filtration can significantly reduce airborne particles

Conclusion

Following the CDC’s recommendations for air exchange rates and ventilation will  significantly impact indoor air quality and help reduce disease transmission. Whether in homes or commercial buildings, maintaining proper air circulation through both mechanical systems and natural ventilation plays a crucial role in creating healthier indoor environments.

By implementing these guidelines and considering advanced air treatment options, building owners and managers can create safer, healthier spaces for occupants while aligning with CDC recommendations for disease prevention.

To learn more, visit the CDC website articles here:

https://www.cdc.gov/respiratory-viruses/prevention/air-quality.html#:~:text=Aim%20for%205%20or%20more,ACH%20to%20your%20existing%20ventilation

https://www.cdc.gov/niosh/ventilation/about/index.html?CDC_AA_refVal=https%3A%2F%2Fwww.cdc.gov%2Fcoronavirus%2F2019-ncov%2Fprevent-getting-sick%2Fimproving-ventilation-in-buildings.html

 

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ASHRAE Standard 241P, Control of Infectious Aerosols

ASHRAE 241: Understanding the Standardized Testing Protocol

The introduction of ASHRAE 241 marks a significant advancement in how we evaluate indoor air cleaning technologies. While our previous post provided a comprehensive overview of the standard, we’ll dive deep into its groundbreaking testing protocol and why it matters for facility managers, building owners, and indoor air quality professionals.

The Problem with Traditional Testing Methods

Historically, manufacturers have tested air cleaning devices in surprisingly small chambers—often no larger than one cubic meter, essentially the size of a shoebox. This approach has led to a critical disconnect between laboratory results and real-world performance. Consider this: you could theoretically show significant pathogen reduction in such a tiny chamber using something as simple as a cigarette lighter—clearly, not a practical or valid solution for indoor air quality management!

ASHRAE 241’s Revolutionary Approach

The new standard addresses these limitations by mandating a testing chamber of 800 ft³ (22.7 m³), approximately the size of a typical office space. This dramatic increase in testing volume creates conditions that much more closely mirror real-world applications, providing more reliable and practical performance data.

Why MS2 Matters

A key component of the protocol is the use of MS2 bacteriophage as the test pathogen. This choice is significant for several reasons:

  1. Superior Challenge: MS2 is a non-enveloped virus, making it more difficult to eliminate than many common pathogens, including:

   – Enveloped viruses (like SARS-CoV-2 and H1N1)

   – Bacteria

   – Fungi

  1. Safety and Practicality: While MS2 is harder to kill, it’s less contagious than viruses like SARS-CoV-2 or H1N1, making it safer for laboratory testing while still providing a rigorous effectiveness benchmark.
  2. Hierarchical Validation: Success in eliminating MS2 effectively demonstrates the capability against easier-to-kill pathogens, providing a comprehensive validation of air cleaning effectiveness.

Impact on the Industry

This standardized testing protocol represents a significant step forward for the indoor air quality industry. For the first time, buyers can make purchasing decisions based on comparable, real-world-relevant performance data. This transparency and standardization help ensure that investments in air cleaning technology deliver the expected results in actual building environments.

The ASHRAE 241 protocol isn’t just about testing—it’s about trust. By establishing these rigorous, standardized testing conditions, the industry now has a clear benchmark for evaluating air cleaning technologies, ultimately benefiting everyone who breathes indoor air.

This blog is a part of a series highlighting the details of 241, so make sure to check out the rest of the series. You can also visit – https://www.ashrae.org/technical-resources/bookstore/ashrae-standard-241-control-of-infectious-aerosols – to learn more and purchase the full standard.

 

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