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In this blog, we take a look at the risks associated with high exposure to CO2 and why monitoring levels of carbon dioxide inside buildings is an important consideration for everyone in order to create a healthy and safer indoor environment.


Although air pollution is typically associated with outdoor environments, it also affects the air we breathe even in enclosed spaces. This issue is especially prevalent nowadays, as people spend the majority of their time in buildings such as schools, work and homes, where both short and long-term exposure to indoor air pollution can cause a range of health issues.


A common air pollutant is carbon dioxide (CO2), a naturally occurring gas which is mainly caused by breathing. Other sources of CO2 include combustion appliances such as gas stoves and fireplaces, building materials, as well as polluted outdoor air that enters the building.


CO2 is measured in ‘parts per million’ or ‘ppm’, and the normal outdoor concentration of CO2 is around 400 ppm while indoor levels can vary depending on factors like ventilation, occupancy and sources of CO2. Although it is generally harmless at low levels, high levels can indicate poor indoor air quality and a build-up of other harmful pollutants, such as volatile organic compounds (VOCs), particulate matter, and biological contaminants. Therefore, monitoring indoor CO2 levels is an important part of maintaining good indoor air quality.


Health risks

Poor air quality can cause Sick Building Syndrome (SBS) which describes the negative health effects experienced when building occupants spend significant amounts of time in an enclosed space. Although it can be challenging to pinpoint the precise causes of sick building syndrome due to the numerous pollutants found in buildings, elevated levels of carbon dioxide are known to contribute to the condition.


The Health & Safety Executive (HSE) identifies issues such as dry or itchy skin, eyes, nose or throat, headaches, lethargy, irritability, poor concentration and a stuffy or runny nose as common complaints that can all be attributed to poor indoor air quality, with CO2 associated symptoms including headaches, dizziness, fatigue, and respiratory problems. SBS can impact the well-being and productivity of almost all occupants in an affected building, so it is important to take precautions in order to ensure the air quality meets the standards and does not cause any short- or long-term health problems.


In extreme cases, high levels of carbon dioxide can be fatal. The Chartered Institution of Building Services Engineers (CIBSE) has published guidance on indoor air quality which recommends that CO2 concentrations in most indoor spaces should be maintained below 1,500 parts per million (ppm), with a maximum acceptable level of 2,000 ppm in areas with high occupant density or pollution sources. The guidance also recommends that CO2 concentrations be measured regularly to ensure that ventilation systems are functioning correctly, and indoor air quality is maintained.


Reducing risk with ventilation

CO2 can quickly increase in poorly ventilated rooms. To maintain good indoor air quality and reduce the risk of health problems associated with high CO2 levels, it is important to ensure that indoor spaces are well-ventilated. This can be achieved through natural ventilation by opening windows and doors, or through quality air purifiers.



However, ventilation alone does not offer complete control over indoor pollution and it is not always easy to implement – for example, when the weather is cold, building occupants will be less likely to open windows, or in an office space, people may want to use a meeting room for private discussion. As such, it is important to use a carbon dioxide monitor that can provide occupants with the CO2 levels and therefore allow action to be taken to ventilate the room if necessary. A monitor that alerts occupants to rising levels in real time is recommended so that occupants have greater chance to take preventative action before the air becomes unhealthy.


In addition to maintaining good indoor air quality for health reasons, CO2 monitors are also useful in energy-efficient buildings where ventilation is reduced to save energy. A CO2 monitor can be used to ensure that the ventilation system is providing adequate fresh air to maintain healthy CO2 levels while still minimising energy usage.


A safe solution

Our CO2 monitor benefits from a 10-year lifespan and provides the current CO2 levels from 400 to 5000 ppm, as well as a seven-day history of CO2 readings. It also shows the current temperature and humidity on the large, easy to read LCD display which comes with automatic brightness adjustment to minimise night-time disturbance.


Notably the monitor uses a ‘traffic light’ visual aid to ensure users can quickly identify and understand the readings, even from a distance. Green represents 400 to 999 ppm, orange denotes readings of 1000 to 1499 ppm, which indicated deteriorating indoor air conditions associated with poor air quality complaints and where preventative action should take place by ventilating indoor space. Red displays for any readings above 1500 ppm – the level associated with headaches, drowsiness and loss of concentration and where it is important to ventilate indoor space as a result. At this level, the monitor’s easily audible built-in alarm clearly alerts occupants to high CO2 levels.


The monitor is suitable for use in a variety of indoor environments, such schools, homes and workplaces and other living spaces and is mains powered with a 12-hour rechargeable battery back-up.


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Helping you to protect your home

It is clear that monitoring plays an important role in managing the impact of CO2. For this reason, our technical teams can help advise to make sure you have the right equipment in all areas of your home. Get in touch today and we will help you choose the right product to suit your needs.