Monitoring indoor air quality (IAQ) is an important way of keeping your building ‘healthy’ for your occupants. However, air quality monitoring technology has advanced massively over recent years, offering an increased range of functionality and sensitivity in capturing data.
Here, we’ll explore what to look for in your air quality sensor to deliver good performance.
How to choose the right monitor for your organisation
1. Measurement parameters
Global building standards recommend monitoring pollutants in regularly occupied spaces within the building, at least once an hour: including particle matter in varying sizes (including PM2.5 & 10 µm), carbon dioxide (CO2), and TVOC, which can be reliably measured, at suitable accuracy, cost-effectively.
Additionally, some also recommend measuing specific volatile organic compounds, formaldehyde, nitrogen dioxide/oxides, ozone, radon, and airborne micro-organisms. However, they may require more complex and costly equipment. In the absence of known risks of exposure, it’s usually reasonable to rely on the more easily measurable parameters to monitor the air quality.
Modern indoor air quality sensors can monitor CO2, TVOCs, and PM (as well as humidity and temperature) all in one device, making them more cost-effective to install.
2. Accuracy and longevity
It’s important to choose an air quality monitor that will provide you with a thorough, clear reading.
Sensors in commercial buildings use two key detection methods: MOS-based chemi-resistors and non-dispersive infrared (NDIR).
MOS sensors are low cost and low power, but can be affected by changes in temperature and humidity, and their sensitivity can be limited. Electrochemical and MOS sensors may eventually lose electrons, and the readings will ‘drift’ — meaning the readings from your air quality monitor can be significantly higher or lower than the true value. Low-quality monitors drift faster because of inferior quality, so they usually need to be replaced after 6 to 12 months.
NDIR sensors tend to be more accurate and reliable, offering high stability and a good measurement range over their typical 15-year lifespan. NDIR sensors are the longest-lasting monitor currently on the market, lasting around 10-15 years. While both electrochemical and MOS sensors have made considerable strides, they are still behind the NDIR.
Some sensors can have a cross-sensitivity bias, which occurs when a substance reacts in the sensor, such as water vapour, changing the electrical properties of the sensor and its readings. You can generally avoid this issue by choosing NDIR sensors.
In addition, the level of accuracy is determined by the calibration done at the manufacturing stage. High-quality indoor air quality monitors go through rigorous and careful calibration and testing processes to ensure high-performing sensors that can provide reliable and accurate readings at all times. So check with your manufacturer to determine what quality-control processes they use.
3. Data and integration
Look for sensors that offer easy and secure access to data. Many sensor providers offer software to analyse your data, but that can come with recurring subscription costs and data ownership issues. If you want to integrate with your own data platform or automate HVAC processes, look for sensor providers that give you the ability to take the data and integrate it with your system of choice.
Pressac sensors are system agnostic – you’re in full control of your data – allowing you to integrate the data into any IoT cloud platform or smart system. Pressac smart gateways send your sensor data securely to your chosen IoT server via your network or 4G – there’s no middleware or subscription fees – enabling you to integrate real-time data into any software application or intelligent building control system.
For more information, see Pressac’s indoor air quality sensor which monitors five air quality factors that can impact health, comfort, and productivity – temperature and humidity, carbon dioxide, total volatile organic compounds, and microscopic particulate matter.
