Nowadays, it is a privilege to have access to a real indoor environment where you can measure and quantify indoor environmental quality (IEQ). It is not an easy task because most companies keep AQ data private, and we totally respect that. However, sometimes tapping into the real world data is fundamental in order to understand the conditions white color employees and employers work in an effort to improve work conditions and productivity.
The owner of the building and the office granted me access to installing the Atmocube IAQ monitor for two months, in order to figure out what improvements shall apply in their effort to mitigate covid19, improve working conditions and boost productivity. The office is located in Almeria, Spain which is a coastal city.
They don’t have any mechanical ventilation systems, so the indoor conditions were subject to their human actions and whether they opened the windows/doors or not.
So many different types of sensors have become available in the market. For years we have seen and used Single (mainly) and Dual-Beam NDIR sensors for CO2 detection, but now another technology has surfaced, the Photoacoustic.
I decided to do a quick comparison of the different technologies in order to determine which one is the best and what are the differences if there is one. Price always affects the Bill of Material BOM, so we need to make a wise choice depending on the application of the sensor (commercial, real estate, industrial, scientific, etc).
Single and Dual Beam NDIR
CO2 is a gas with an asymmetric molecular structure that has strong absorption of infrared. This is the reason we use a Non-Dispersive Infrared NDIR sensor which is based on tunable diode laser spectroscopy.
More and more people choose to ride a bike for their daily commutes and although SODAQ AIR is not the first air quality monitor for a bike, it is the first to have collected over 20M data points. This is particularly import for the development of an IoT air quality monitor as the developers have enough information to debug and develop a super stable product that needs very little troubleshooting from its users.
SODAQ is not a new company as it was founded back in 2013, and they have been working on this particular project (SODAQ AIR) alone since 2015. It seems that consumer satisfaction is always their priority, which is very important nowadays as we need sustainable products that will last for a long time.
In the space of ambient air quality monitoring, there are two basic and distinctive categories of professional air quality monitors; the High-End Professional and Low-Cost Professional monitors. I have been asked multiple times to recommend monitors for scientific studies and the deployment of them in cities.
It is very important to understand the strengths and weaknesses of both categories. It is also mandatory to recognize the fact that we will never get the exact same measurement from either category of sensors.
High-End Professional AQA
High-End Professional ambient air quality analyzers are used mostly by governments inside the air quality stations we have in most cities. Their strength is that they meet international standards for accuracy and they are certified by the EU (and similar bodies) to meet minimum performance requirements, in order to ensure that the measurement methods comply with the Data Quality Objectives set down in the Ambient Air Quality Directive (2008/50/EC) and in the amending Directive (EU) 2015/1480. Their weakness is that they require lots of energy to operate. In most cases, they are inside a fixed container with a refrigeration system to keep conditions stable. They are big and boxy in size and very expensive to purchase and operate. Additionally, they need constant maintenance by a technician. Another weakness is that in most cases these analyzers are not smart enough to broadcast measurement in real-time to the Cloud and they require other pieces of equipment to do that job, as a result, the cost of operation increases.