How CO2 Gas Sensors Could Help Control COVID-19

By Ben PilkingtonNov 19 2020

Image Credit: Halfpoint/Shutterstock.com

Market analysts have recently predicted the rise of an emerging market for CO₂ gas sensors to help control the spread of COVID-19. This emerging market contributes to a growth in the total market for environmental gas sensors, which is forecast to reach $3.8 billion by 2030.

CO₂ Gas Sensors Recommended by REHVA

This follows recommendations from the Federation of European Heating, Ventilation and Air Conditioning Associations (REHVA) to use CO₂ gas sensors with traffic light indication to help ensure good indoor air quality.

REHVA says that installing a CO₂ monitor with traffic light indication in rooms that depend on opening windows or grids for ventilation can help visualize the need for extra ventilation and help people keep the overall indoor air quality high. It instructs the CO₂ gas sensor should be placed in a visible position and away from fresh air inlets.

REHVA also suggests adjusting settings on traffic light indicators to show amber and red alerts at lower parts per notation (PPN) readings to promote maximum ventilation and fresh air.

Although directed at school buildings in Europe, this advice can apply to any commercial or public facility with manual indoor air quality (IAQ) systems and a concern for its occupants’ health and safety.

The REHVA’s US counterpart, The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHAE), has also issued COVID-19 guidance for building managers, which includes recommendations to check CO₂ gas sensors and ensure good IAQ and fresh air to help control COVID-19’s spread in their buildings.

Market analysts believe that this advice will be followed by building managers, government agencies, and public health advisors globally, driving a new market for CO₂ gas sensors.

The emerging market is also reacting to state intervention in the fight against COVID-19. For example, the German government recently invested €500m ($488m) to improve ventilation systems in public buildings, making funding available specifically for the installation of CO₂ sensors to indicate low IAQ – a factor in the likelihood of COVID-19 infection.

COVID-19’s Triple Infection Threat

After much research and discussion in the past year, it is now generally agreed that COVID-19 spreads through three routes: via larger respiratory droplets (which fall to the ground one or two meters from the person emitting them), via direct contact with infected surfaces, and via smaller respiratory droplets which remain suspended in uncirculated air as aerosols.

While the first two routes have been widely recognized for some time – leading to the implementation of social distancing and hygiene guidelines and procedures worldwide – the aerosol route has only recently been taken seriously by authorities.

Emerging research suggests that most COVID-19 transmissions occur indoors. This is because SARS-CoV-2 can remain active suspended in indoor air for up to three hours. It also remains active on surfaces for up to 2-3 days under common indoor conditions.

The Importance of Building Controls

The advice to building controllers – which analysts predict will drive significant growth in the CO2 gas sensor market – indicates their essential role in disease prevention and control.

The US Centre for Disease Control (CDC) and the broader field of disease control and prevention operate with a traditional infection control hierarchy, emphasizing the importance of building management: the Hierarchy of Controls.

This hierarchy places elimination (physically removing the pathogen) at the top of a priority list, followed by engineering controls (separating people from the pathogen), administrative controls (telling people what to do), and personal protective equipment.

Ventilation controls – such as CO₂ gas sensors – are a type of engineering control. They separate people from the pathogen by ensuring good IAQ and a ready supply of fresh air, increasing the chances that any pathogens will leave the building.

Building engineering controls such as these can be implemented with minimal cost, either in money or effort. Therefore, they are making up a critical factor in advice and guidance seeking to control the spread of COVID-19.

REHVA: Practical Tips for Maintaining Good IAQ to Help Control COVID-19

REHVA has given practical tips for maintaining good IAQ in its advice document for schools that all building managers can apply. These include:

• Check whether ventilation systems are functioning well (check grids and windows can be opened, check air supply is unobstructed, have maintenance provider check mechanical ventilation systems).
• Install CO₂ monitors with traffic light indication in rooms where ventilation depends on manual control (such as opening windows).
• Check when mechanical ventilation systems will operate, ensuring toilet systems are working 24/7 and that all systems are operating for two hours before and after buildings open.
• Systems with indoor air circulation should be switched to 100% outside air.
• Adjust setpoints in automated mechanical systems – such as CO₂-controlled ventilation systems – to ensure constant ventilation despite low occupancy.
• Instruct staff on how to properly use building ventilation systems.

REHVA has also published and updated guidance for all building managers regarding the use of HVAC systems and plumbing during the COVID-19 pandemic. Using CO₂ gas sensors to ensure good overall IAQ is recommended as a relatively cheap and practical measure to help control COVID-19.

References and Further Reading

ASHRAE (2020) “Building Readiness.” ASHRAE. https://www.ashrae.org/

BBC News (2020) “Coronavirus: Germany Improves Ventilation to Chase Away Covid,” October 19, 2020. https://www.bbc.com/news/world-europe-54599593.

CDC (2015) “Hierarchy of Controls.” CDC. https://www.cdc.gov/niosh/topics/hierarchy/default.html.  

Doremalen, Neeltje van, et al. (2020) “Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1.” New England Journal of Medicine. https://doi.org/10.1056/nejmc2004973.

IDTechEx (2020) “An Emerging Market for CO2 Gas Sensors to Assess COVID-19 Transmission Risk, IDTechEx Reports.” PRNewsWire. https://www.prnewswire.com/news-releases/an-emerging-market-for-co2-gas-sensors-to-assess-covid-19-transmission-risk-idtechex-reports-301171110.html.

Morawska, Lidia, and Junji Cao (2020) “Airborne Transmission of SARS-CoV-2: The World Should Face the Reality.” Environment International. https://doi.org/10.1016/j.envint.2020.105730.

Morawska, Lidia, et al. (2020) “How Can Airborne Transmission of COVID-19 Indoors Be Minimised?” Environment International. https://doi.org/10.1016/j.envint.2020.105832.

Nishiura, Hiroshi, et al. (2020) “Closed Environments Facilitate Secondary Transmission of Coronavirus Disease 2019 (COVID-19).” Preprint article. https://doi.org/10.1101/2020.02.28.20029272.

REHVA (2020) “Guidance for School Buildings.” REHVA. https://www.rehva.eu/fileadmin/user_upload/REHVA_COVID-19_Guidance_School_Buildings.pdf.

REHVA (2020) “COVID-19 Guidance Document.” REHVA. https://www.rehva.eu/fileadmin/user_upload/REHVA_COVID-19_guidance_document_V3_03082020.pdf.

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