Croatia - Flag Croatia

All prices include duty and customs fees on select shipping methods.

Please confirm your currency selection:

Free shipping on most orders over 50 € (EUR)
All payment options available

US Dollars
Free shipping on most orders over $60 (USD)
All payment options available

Bench Talk for Design Engineers

Bench Talk


Bench Talk for Design Engineers | The Official Blog of Mouser Electronics

Why Monitor CO2 Levels in Classrooms? Jeffrey Tucker

(Source: Amphenol)

What do you look for in a school district? Quality of teachers? Reputation? How do their sports teams and extra-curricular activities stack up? Do you ever think about the indoor air quality in the school buildings? In 2014, the US estimated that the average age of the nation’s main school buildings was 55 years old based on a sample of school districts. Nearly half of these buildings reported problems related to indoor air quality (IAQ).

Environmental Protection Agency (EPA) studies of human exposure to air pollutants indicated that indoor air levels of pollutants could be two to five times—and occasionally more than 100 times—higher than outdoor levels. The concern is most people spend about 90 percent of their time indoors.

Read on to learn why CO2 level is a good indicator of indoor air quality (IAQ) and how good IAQ contributes to school success.

What Is IAQ?

The EPA defines indoor air quality (IAQ) as the air quality within and around buildings related to the building occupants’ health and comfort. Understanding and controlling common pollutants indoors can help reduce your risk of indoor health concerns.

Pollutants are not the only concern. Temperature and humidity must factor into this because thermal comfort conditions are a main contributor to poor air quality. Good IAQ is an important component of a healthy indoor environment and can help schools reach their primary goal of educating children. The health and comfort of students and teachers contribute to learning and productivity in the classroom, which in turn, affect performance and achievement.

Failure to prevent or minimize IAQ problems can increase long- and short-term health effects for students and staff. Some of these health problems can include coughing, eye irritation, headaches, allergic reactions, aggravating asthma, and/or other respiratory illnesses. Any or all of these can affect student attendance, focus, and achievement, as well as reduce teacher and staff performance.

Determining Indoor Air Quality

But how do you know if the air quality is good? The most obvious method is to ensure that a room is properly ventilated, which aids in maintaining a high level of indoor air quality. CO2 contributes to poor air quality. Every time you exhale, you release CO2 into the air. Monitoring the CO2 level helps you determine if the room is properly ventilated with fresh outside air, thereby helping you gauge the indoor air quality within that space.

Effects of High CO2 Levels

Studies found that high levels of CO2 can impair cognitive ability. This can affect the ability to make decisions, maintain a high quality of work, or learn and communicate effectively. As a result, IAQ can significantly influence workplace productivity, educational learning, and patient recovery in hospitals. Table 1 reflects the physiological response by humans to various levels of indoor CO2.

Table 1: Physiological response to CO2 Levels (Source: Wisconsin Department of Health)

Monitoring CO2 Levels

Under normal circumstances, CO2 sensors, when connected to the energy management system (EMS) in a demand-controlled ventilation (DCV) scenario, monitor the CO2 levels within a space. Based on the respective CO2 level, which is also a good proxy of the number of occupants in the room, the EMS will determine the amount of fresh outside air to introduce into the space. This method is used to ensure that the space is properly ventilated while saving energy. In general, under this circumstance, the CO2 levels are maintained ≤1000ppm of CO2. However, during the recent and ongoing COVID-19 pandemic, the CDC made several recommendations to minimize exposure to the SARS-CoV-2 virus particles. One recommendation is to disconnect the DCV system and increase the amount of fresh air necessary to maintain CO2 levels between 600ppm-800ppm, while paying attention to the humidity and comfort levels within the space. Maintaining the lower CO2 level within a space helps minimize the chance of transmitting the virus if an infected person is inside the space.

If too little outside air is introduced into the building, pollutants can accumulate to levels that can pose health and comfort problems. Unless buildings are constructed to include a mechanical means of ventilation, the amount of outdoor air that can leak in and out of the building can be insufficient to provide quality indoor air conditions and result in higher indoor pollutant levels. Improving and maintaining proper indoor air quality can reduce the number of student visits to the nurse’s office, reduce absenteeism because of illness, and enhance all students and staff’s general health and well-being.

Air quality in schools is of particular concern. Proper maintenance of indoor air is more than a “quality” issue. Quality indoor air encompasses safety and stewardship of the investment in students, staff, and facilities. Because monitoring and improving CO2 levels are critical to a school’s success, school districts need highly accurate sensing technology.

Telaire CO2 Modules

Amphenol Advanced Sensors’ portfolio of industry-leading brands includes Telaire. Telaire has been at the forefront of CO2 sensing technology for over 25 years and is the originator of the maintenance-free CO2 Non Dispersive Infrared (NDIR) sensor. Amphenol Advanced Sensors offers a complete line of Telaire CO2 modules and transmitters for your indoor air quality monitoring needs. You can find this complete line here:


The CO2 level is a good indicator of whether the space is properly ventilated and maintains a high level of air quality. Quality indoor air provides the students and staff the atmosphere needed to perform at their best.

The Why Monitor CO2 Levels in Classrooms? post was first published on the Amphenol Sensors website and reprinted on with Amphenol’s permission.

« Back

Jeffrey Tucker is a Field Application Engineer for the industrial segment of Amphenol Advanced Sensors (AAS). Prior to coming to AAS Jeffrey was a design/build mechanical contractor (HVAC, hydronic systems, process systems, plumbing systems, & temperature controls) and director of retrofit solutions (mechanical) with over 25-years’ experience in the commercial and light industrial market. Jeffrey is a graduate of California Coast University and the US Naval Nuclear Power School. Jeffrey is a Certified Energy Manager (CEM), a Certified Measurement & Verification Professional (CMVP), and a LEED Green Associate. Jeffrey can be reached via email at

All Authors

Show More Show More
View Blogs by Date