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ANSI COVID-19 News: CDC Updates Building Ventilation Guidelines and Sewer Surveillance Tracks COVID


The ANSI Federation and standardization community are stepping up with guidance, resources, and initiatives to support public health and safety and the nation's recovery. Suggestions for news items may be submitted to [email protected]. All submissions are published at ANSI's discretion.

How Much Ventilation is Enough? CDC Updates Guidelines for Clean Air in Occupied Spaces

The Centers for Disease Control and Prevention (CDC) has updated its guidelines for ventilation in buildings, with a recommendation to provide at least five air changes per hour (ACH) of clean air to rooms in occupied spaces and guidance to upgrade to MERV-13 filters.

The CDC recommends, when possible, to aim for five or more ACH of clean air to help reduce the number of germs in the air. “This can be achieved through any combination of central ventilation system, natural ventilation, or additional devices that provide equivalent ACH (eACH†) to your existing ventilation,” the CDC reported. To that end, the CDC explains that that five ACH will not guarantee totally safe air in any space, but it reduces the risk of exposure to germs and other harmful air contaminants.

The health agency also recommends upgrading the central HVAC filter efficiency to a Minimum Efficiency Reporting Value (MERV)-13 or better. “When compatible with your HVAC system, increased filtration efficiency is especially helpful when enhanced outdoor air delivery options are limited,” according to the CDC.

Access the complete listing of CDC’s guidelines (updated on May 12) on its Ventilation in Buildings webpage.

Wastewater Data Can Support COVID Tracking Efforts

Wastewater surveillance may be an increasingly important strategy to track new variants of COVID-19 and assess the threats they may pose to public health, according to scientists.

People who are infected with the coronavirus shed the pathogen in their stool. The New York Times recently highlighted national efforts to track COVID through sewage in an article featuring scientists including Amy Kirby, CDC microbiologist and program lead of the CDC’s National Wastewater Surveillance System (NWSS), launched in 2020. NWSS works with health departments to track SARS-CoV-2 levels in wastewater so communities can act quickly to prevent the spread of COVID-19.

NWSS now includes data from more than 1,400 sampling sites, distributed across 50 states, three territories, and 12 tribal communities. Overall, the data cover about 138 million people, which accounts for more than 40 percent of the U.S. population, The Times reported.

“Wastewater sampling helped scientists determine when new variants arrived in particular communities and helped clinicians make more informed decisions about when to use certain treatments, which may not work against all versions of the virus,” according to the article.

Other efforts to track biological and chemical contaminants on a community level are underway. As ANSI previously reported, the National Institute of Standards and Technology (NIST) is partnering with the Department of Homeland Security Science and Technology Directorate (DHS/S&T) to develop documentary standards and reference materials to support an enduring capability in wastewater surveillance.

See more ANSI member efforts in the ANSI COVID-19 Resource Webpage Highlighting Standardization Community Response

Related News:

ANSI COVID-News News: How Clinical Research is Helping People with Long COVID, and Wastewater Surveillance Efforts.


Jana Zabinski

Senior Director, Communications & Public Relations


[email protected]

Beth Goodbaum

Journalist/Communications Specialist


[email protected]