Rewind a few years and carbon dioxide monitoring was not something many businesses would have had cause to think about. But, like facemasks, social distancing and hand sanitiser, it’s now something that most have had to familiarise themselves with pretty quickly.
As organisations have grappled with making their workplaces as Covid-secure as possible, the importance of monitoring air quality and the effectiveness of ventilation systems has come to the fore.
Installing CO2 monitors is one of the easiest ways to do this and was referenced in Government guidance last year which stated companies should “consider using a CO2 monitor to identify poor ventilation.”
But how exactly does it work? And what monitors should you be using? This article looks at the key points you need to know when considering introducing CO2 monitoring in your business.
What is carbon dioxide?
We all know what carbon dioxide is. It’s a trace gas in the atmosphere, it’s what we breathe out and plants breathe in, and there’s too much of it around, and that’s bad for the planet, but why does that matter to us individuals, day to day?
As well as being bad for the environment, carbon dioxide is very bad for us. It only makes up a tiny percentage of the air, so you can’t sense when the CO₂ levels increase, but it has significant and measurable effects on the human mind and body. CO2 exists in the atmosphere, and typical outdoor air contains around 500 ppm of CO₂, which is perfectly harmless, but modern buildings have been designed to seal off the outside world to save energy. This reduces natural ventilation and leads to a build-up of CO₂ wherever people congregate.
How do CO2 monitors reduce the risk of viruses spreading?
CO2 monitors work by giving an indication of how well-ventilated an area is, and therefore the potential concentration of a virus in the atmosphere.
People breathe out CO2, and someone who has an airborne virus (like Covid) will also breathe out small particles of the virus. If the concentration of CO2 in a room is high it means the potential for any Covid particles is also high. If a room is well-ventilated the amount of CO2, and therefore the amount of viral particles, is reduced.
CO2 monitors help to identify any areas of poor ventilation, allowing you to make the necessary changes to keep fresh air flowing, whether that be via mechanical ventilation or ensuring doors and windows are open.
They measure the concentrations of CO2 in parts per million (ppm).
Are there any other benefits of CO2 monitoring?
As well as helping to reduce the potential transmission of germs, CO2 monitoring can also ensure a more pleasant environment for employees and aid productivity.
Studies have shown that high levels of CO2 can make occupants of a room feel drowsy, reduce their cognitive performance, cause headaches and affect concentration.
How do CO2 monitors reduce the risk of viruses spreading?
CO2 monitors work by giving an indication of how well-ventilated an area is, and therefore the potential concentration of a virus in the atmosphere.
People breathe out CO2, and someone who has an airborne virus (like Covid) will also breathe out small particles of the virus. If the concentration of CO2 in a room is high it means the potential for any Covid particles is also high. If a room is well-ventilated the amount of CO2, and therefore the amount of viral particles, is reduced.
CO2 monitors help to identify any areas of poor ventilation, allowing you to make the necessary changes to keep fresh air flowing, whether that be via mechanical ventilation or ensuring doors and windows are open.
They measure the concentrations of CO2 in parts per million (ppm).
Are there any other benefits of CO2 monitoring?
As well as helping to reduce the potential transmission of germs, CO2 monitoring can also ensure a more pleasant environment for employees and aid productivity.
Studies have shown that high levels of CO2 can make occupants of a room feel drowsy, reduce their cognitive performance, cause headaches and affect concentration.
For example, this study:
The participants were given a variety of tasks to perform in nine different areas while exposed to different concentrations of CO₂.
You can clearly see the pattern here – higher levels of CO₂ clearly have an affect on our decision-making abilities. Take a look at the “initiative” graph in particular – when exposed to just 2500 ppm of CO₂, our ability to use initiative drops to almost zero! 2500 ppm is high, but not unheard of. A stuffy and poorly ventilated room can easily exceed 3000 ppm, with a massive effect on the performance of people working in that space.
Academic performance is also massively affected. A Harvard study found that increasing CO₂ levels by just 400ppm can impact a student’s cognitive function by 21%.
Not many people think of a CO₂ sensor as an energy saving device – but if you measure what is in the air, not only can you ensure that you get the best possible performance out of anyone working in that space, but you can also ensure that the ventilation is running at the optimal level, without wasting any more energy (click to read our case study).
With Pressac’s CO₂ sensors, you can track your CO₂ levels in real time, and adjust the ventilation accordingly. Keep your air quality high, get the best performance out of your staff, and save energy all at the same time. By analysing the data from air quality sensors, you can make live adjustments in the HVAC systems to ensure the maximum possible comfort levels, and watch your productivity increase.
Place CO₂ sensors around your office space to see where the problem spots are in your ventilation system, and make sure to keep your office air clean and your staff comfortable.
What are the safe levels of CO2?
Ideal measures vary depending on the size of a space and what it’s being used for but, as a general rule, a consistent reading of below 800ppm indicates an area is well-ventilated – although it’s important to remember that this would not mean a room is free of Covid, simply that there is less chance of multiple people being infected with it.
If the level of CO2 is consistently higher than 1500ppm a room is deemed to be poorly ventilated and action would be needed to remedy this.
What type of monitor do I need?
There are a range of CO2 monitors on the market but the UK Government’s scientific advisers recommend NDIR (non-dispersive infra-red) technology.
A report by the Scientific Advisory Group for Emergencies (SAGE) states that other types of monitor “should be avoided” due to their potential inaccuracy [2].
It adds that “sensors using NDIR technology are widely shown to give more reliable readings.”
NDIR sensors work by using specific wavelengths of light to measure the amount of CO2 in the air. The more CO2 present, the more light the sensor will absorb.
NDIR sensors are relatively low cost compared to other monitoring technology and are very long-lasting – some will last for up to 10 years before they need replacing. They also work well at common CO2 ranges (0-2550 parts per million).
What do I need to consider when installing CO2 monitors?
The positioning of CO2 monitors is crucial in ensuring the most accurate readings and it’s important for building managers to work closely with the staff that work within a space to ensure they have a clear picture of how it is used. This enables monitors to be placed in optimum positions for best results.
As a general rule, they should be at head height and kept away from windows, doors or air conditioning units.
They should also be at least 50cm away from any individual.
In larger spaces several monitors will be needed.
CO2 levels can fluctuate throughout the course of a day, and the guidelines on safe levels are based on a consistent reading, therefore multiple readings should be taken throughout the day to gain an accurate picture of overall levels of CO2. Activity levels within the room should also be taken into account as high activity levels can result in four times the amount of CO2 emissions compared to when people are sitting still.
The SAGE report contains a useful table on the suitability of CO2 monitoring in different types of spaces.
How can the data from CO2 monitors be used?
The CO2 data collected by smart sensors can be used for monitoring values or trends over time, to alert facility managers to issues, or to automate building controls.
It can, for example, be fed into a data analytics system for monitoring and identifying peaks, so you can quickly make changes when things appear not to be running as they should be. If, for example, they sense high CO2 in an area where this would not normally be expected, this could indicate a problem with part of the air-conditioning system. This will potentially be picked up at a much earlier stage than it would have been without sensors, meaning repairs can be made before the problem becomes much more difficult and expensive to fix.
It can also be fed into Building Management (BMS) or Building Automation Systems (BAS) for automated, on-demand HVAC delivery based on actual real-time usage of spaces – increasing wellness and productivity, and improving energy efficiency by allowing enabling systems to be turned down of off when not needed.
If you would like advice on installing CO2, and/or other air quality monitors, in your workspace Pressac’s expert team can help you find the best options. Contact them here.
[1] https://www.hse.gov.uk/ventilation/assessing-the-risk-of-poor-ventilation.htm
