Understanding the Role of CO2 Monitors in COVID-19 Prevention Strategies

Understanding How Virus Transmission such as COVID-19 is Increased in Indoor Environments

Viruses, such as COVID-19 can be transmitted through airborne contaminants – otherwise known as aerosols.  Released into the air through acts such as breathing, talking, or coughing, virus particles generally attach to larger particles such as dust or saliva and can typically travel one to two metres, however this is not always the case with smaller droplets travelling much further. Due to this potential, social distancing can be effective for viruses such as COVID-19, but further measures are required to mitigate the risks of virus transmission. 

Outdoors, the risk of transmission is minimised due to natural air flows refreshing the air but in enclosed spaces, these aerosols - containing virus particles, can remain suspended in the air long after the infected person has left the space. This tendency to linger in the air is one of the factors in why improving ventilation can help minimise the transmission risk - in conjunction with traditional measures such as face masks and social distancing. This article will discuss the importance of ventilation and how you can identify indoor spaces with insufficient air circulation using devices such as Carbon Dioxide Monitors.

How Ventilation Plays a Vital Role in Reducing Virus Transmission

Ventilation can play a large part in mitigating the risk of airborne transmission indoors, with aerosols and virus particles accumulating within enclosed spaces. Options such as natural or mechanical ventilation systems can provide a solution by cycling fresh air through the space and diluting the airborne contaminants.

Whilst it can be hard to visualise how increased airflow can work to reduce the risk, Professor Geoff Hanmer, member of OzSAGE and from the University of Technology, Sydney, links the accumulation of COVID indoors to cigarette smoke saying “it builds up and is removed in the same way, but you can’t see it. Just as workplaces must be free of smoke, we must provide fresh air and sometimes filters and masks to protect workers and visitors. By ensuring we breathe fresh air, we can avoid most covid transmission.”

This inability to see the build-up of gasses and aerosols implies that in order to understand the quality of the air in the room, quantitative data is required, usually by means of monitoring CO2 concentration levels.

The Role of CO2 Monitors in COVID-19 Prevention Strategies

In every breath humans exhale, approximately 4-5% of the expelled gasses is carbon dioxide. Therefore, when people are present in an indoor space, the measuring of carbon dioxide (CO₂) concentration levels can indicate how much fresh air is circulating and whether adequate dilution is occurring. This has led many states across Australia to identify that a combination of ventilation assessments, carbon dioxide monitors, particle filters in conjunction with other strategies such as social distancing and mask-wearing as mitigation strategies for managing virus transmission as Australia begins to reopen to a post-covid economy.

Director of the Environmental Science Hub at the University of Melbourne, Robyn Schofield believes that carbon dioxide sensors are extremely useful to identify issues with poor indoor ventilation and the associated increase in the risk of transmission, saying that there is an indication that CO₂ levels above 850 parts per million are “unacceptable” for the COVID-19 delta strain. For context, outside concentration levels of CO2 is approximately 400ppm while a typical office environment will be between 600-800ppm. Ideally, CO2 concentration levels should be kept below 1000ppm.

As noted by Certified Occupational Hygienist (COH) Brian Murphy from EHS Assess during our webinar on Indoor Air Quality in schools; whilst CO₂ sensors can indicate when there is an increased risk of transmission due to insufficient airflow or stale air- allowing for preventative measures to be taken - CO2 monitors cannot directly prevent virus transmission. They can only indicate how effective air circulation is. They also cannot identify the SARS virus nor COVID directly.

How to Use Data from CO2 Monitors to Provide Healthy and Safe Indoor Environments

With an increased risk of virus transmission in poorly ventilated spaces, it is highly important to actively monitor and understand how well air is circulating within an area at different times of the day. Access to this information can assist users in making informative data-driven decisions into the correct ventilation solution required for the space. 

CO₂ monitoring devices such as the Elsys ERS CO₂ Carbon Dioxide Sensor are designed to monitor a range of indoor air quality parameters such as CO2 levels, temperature, humidity and more. The information collected provides a comprehensive view of the volume of fresh air entering a space and can give users information on how each individual space is influenced by evolving factors such as occupancy, activities, and external forces like weather conditions. The data is provided in real-time allowing for users to increase air circulation as the requirements of the space change by simple actions such as opening windows or increasing operations of mechanical ventilation systems. The ERS CO2 Carbon Dioxide sensors can help inform you on your building’s indoor air quality.