Are air quality monitors accurate? How accurate is accurate enough?

If your role involves measuring air quality, you know how crucial it is to capture accurate data and you might be wondering, “are these air quality monitors accurate enough for my project?”. However, determining the accuracy of modern-day air quality monitors is more complex than just knowing their range. To make informed decisions about air quality and protect people, you need a reliable air quality monitor suitable for your specific application. Different types of monitors are out there to choose from:

– Commercial monitors: similar to personal monitors by measuring many parameters, but have been designed to work within the environment with enhanced connectivity and automation capabilities so that you can leave them alone for continuous monitoring
– Reference-grade monitors: often called lab-grade monitors, these are highly accurate but are not practical for most applications as they are very large in size, less user-friendly and significantly more expensive, and are therefore generally reserved for use by governments and scientific research in baseline monitoring
– Consumer-grade monitors: these monitors are the cheapest on the market, but provide less accuracy and features than commercial and lab-grade air quality monitors, making them only suitable for home and personal use

Air quality monitors can come with different sensor types to measure different air quality parameters such as particulate matter, CO2, VOCs, and Ozone. Once you have chosen an air quality monitor that measures the parameters relevant to your application, variables such as installation location and placement can affect the accuracy of your data.

So, how accurate do air quality monitors need to be?

It’s worth noting that for air quality monitors used on building sites, commercial or residential settings, having the most precise and accurate reference-grade monitors will not always be essential.

Commercial-grade combines the relative affordability of consumer-grade monitors with the powerful features for the built environment of lab-grade air quality monitors.

When choosing an air quality monitor, your main focus should be on selecting a monitor based on the parameters that you wish to measure, whether you prefer a cloud-based or offline data collection method, which type of software you require to interpret the data, and what your maintenance plan will be to keep your sensors accurate if you plan on long-term monitoring.

That way, with optimal installation location and placement (more on that below), you are in a strong position to gauge the overall quality of the air to make informed decisions and meet health & safety standards, rather than achieving pinpoint precision in measuring a specific pollutant as you would with pricey reference-grade monitors.

Commercial monitors on the market have come a long way, and many use highly accurate sensors such as non-dispersive infrared (NDIR) CO2 sensors (see the TSI BlueSky), which are most suitable for office and commercial settings. For measuring other common outdoor pollutants such as Ozone, many commercial air quality monitors use electrochemical sensors which are less susceptible to cross-contamination with nitrogen dioxide than MOS sensors and provide more consistent readings.

To make the most out of your air quality monitor, ensure that you: 

• Place monitors in the most frequently occupied spaces, even if that means one in each room for IAQ
• Install monitors in the zone where people breathe (3-6 meters up from the floor)
• Place monitors at least 5 meters away from windows, air filters, and diffusers as these can skew results
• Place at least one monitor on all floors for areas with multiple floors
• Place enough monitors to cover the entire space for open large spaces

For further information, request a price list here, email london@ashtead-technology.com or call 01462 679 020.