Collaboration: Gas Sensing Solutions and CO2Meter.com
How does CO2 Influence Air Quality (IAQ)
The established benchmark test for indoor air quality is to assess CO2 levels. Ignoring particulate matter, VOCs, and other contaminants, it is generally understood that indoor CO2 levels are a good proxy for the amount of pollutant dilution in densely occupied spaces and can therefore be used as a good indicator for fresh air.
The amount of carbon dioxide (CO2) in a building is usually related to how much fresh air is being brought into the building.
In general, the higher the concentration of carbon dioxide in the building in comparison to outdoors, the lower the amount of fresh air exchange. The background level of CO2 outdoors is generally considered in the range of 350-450 parts per million (ppm). CO2 is a by-product of normal human activity and is removed from the body via the lungs in the exhaled air. Unless an indoor space is adequately ventilated, CO2 will naturally build up over time. CO2 levels in a well-managed indoor space are generally 450 - 1,000ppm. Above 1,000ppm generally states that most people will begin to complain about the stuffy atmosphere or poor air quality. High levels of CO2 indoors are also associated with headaches, sleepiness, poor concentration, and loss of attention; and in extremely high concentrations CO2 is harmful to life due to oxygen deprivation.
Carbon Dioxide monitoring therefore serves as a vital tool for monitoring indoor air quality (IAQ) and preventing air-borne illnesses such as COVID-19 from traveling throughout indoor environments. For those individuals across homes, offices, classrooms, gymnasiums, and even commercial buildings; specific elevated concentrations of CO2 levels have led to severe negative health effects if not properly monitored. For example, everyone knows the all too familiar scenario where team members pile into a meeting room for an annual or quarterly discussion, only to find many of their peer's performance seeming to drop sharply as the last few minutes are remaining.
This drop in performance or "lack of focus" is most likely due to the poor indoor air quality and high concentrations of CO2 in the space.
Additionally, with the most recent COVID-19 pandemic, individuals are now more than ever aware of the importance of improving indoor air quality - as the average human spends 90% of their time indoors. With the EPA reporting that indoor air can be anywhere from 2 - 5x more polluted than outdoor air, the need to mitigate air borne illnesses and improve cognitive abilities could not be of more importance.
Hence, CO2 sensors. With CO2 sensors and technologies, individuals can gain clear indication of just how much "filtered" air they are breathing based off the CO2 concentrations, as well as recognize when a room requires more ventilation. To prevent or reduce high concentrations of CO2 in a building or room, fresh air should be supplied to the area. Furthermore, once a CO2 sensor notifies an individual that the CO2 levels are too high, individuals find that once opening a window or entry way they gain back the productivity, focus, and energy they were lacking- three main areas where poor IAQ often influences.
A common trend that is also prevalent in IAQ application, is energy audits. These audits focus solely on monitoring energy efficiency in buildings and mitigating serous health and comfort concerns or standards. By monitoring CO2 levels in smart homes and commercial buildings, individuals can also often decrease gas and electric bills while further improving upon their own health and well-being.
To provide a quick helpful resource, we have linked the CO2 Classification Guide here, which showcases the proper CO2 levels between what signifies "normal outdoor levels" vs. "poor indoor air quality" and the OSHA/ASHRAE recommended comfort standards.
By analyzing the chart above you will gain the necessary knowledge on what levels require more ventilation and in turn can create healthier environments.
How to Measure CO2 in Indoor Air Environments
CO2 monitoring systems often need to be installed and located where access to main power is limited, or its provision is costly. CO2 sensor location is often a compromise between the best place for gas mixing and access to the necessary power and communications infrastructures. Historically, CO2 monitors have typically been designed as a small white box on the wall by the door. However, increasingly, IAQ monitors are being installed in ducting and immediately are adjacent to the room.
The ability to be able to power the CO2 sensor for longer periods of time from a battery or from energy generated using harvesting techniques is therefore highly desirable. To reduce maintenance costs, users want the ability for the CO2 sensor to operate autonomously for many years without user intervention.
NDIR Carbon Dioxide (CO2) Sensor Technologies
When we discuss CO2 sensors in indoor air quality, Non-Dispersive Infrared of NDIR technology is typically the most common type of method in measurement. This is because the NDIR technology is based on a high-quality spectroscopy of an IR lamp that emits a beam of light. Additionally, there is an inverse relationship between the amount of CO2 in the gas sample and the amount of IR light detected at the target energy level. When there is no CO2 in the chamber, all the IR light will reach the detector. The greater the concentration of CO2 in the gas sample, the greater the IR light absorbed at the energy and the less IR light that is detected by the IR detector.
Using this precise measurement principle, enables CO2 sensors to be able to calculate the approximate concentration of CO2 in the gas sample in parts per million or "ppm".
Today's newest generation of NDIR CO2 sensors like those from Gas Sensing Solutions (GSS), encompass even more optimization and allow for a longer optical light path, lower power levels, and provide a much longer life span for the end user. Typical applications that require NDIR technology in monitoring CO2 levels include those in indoor air quality, HVAC, smart home technology, architecture, construction, and engineering.
All GSS sensors use an in-house designed ultra-efficient LED light source. LEDs are much more efficient at converting electrical power into light than conventional light sources and they do not need the long warm up times suffered by incandescent light sources. The length of time the light source is active is a major contributor to how much power is consumed by the sensor. In a power sensitive application, a GSS CO2 sensor is typically "pulsed on" to take a measurement and then powered off to minimize overall power consumption.
GSS COZIR® CO2 Sensor Solutions
The latest GSS sensors such as the CozIR®-Blink are designed to operate in battery powered wirelessly connected IAQ units so they can be easily installed and deployed.
They are designed to be power cycled, where the whole device is powered down after a CO2 reading has been made. A typical installation might be pre-programmed to take one reading every few minutes. Depending on the required CO2 measurement accuracy, if the sensor is configured to take a reading every minute, the power consumed by the CozIR®-Blink can be as low as 26uW per reading. While obviously dependent on what other electronics are in the sensor, CO2 monitors using the CozIR®-Blink are often designed to last for two or more years on a single battery charge.
Because Carbon Dioxide (CO2) is a result from human respiration and metabolism, concentrations are often required to be monitored throughout many of our customer use cases. At CO2Meter for example, we work alongside a variety of applications and recommend CO2 sensors such as the GSS CozIR®-A 10,000ppm CO2 Sensor and CozIR®-LP3 1% CO2 Sensor. Both technologies hold incredibly ultra-low power, accuracy, and easily integrated into indoor air quality (IAQ) applications for individuals across the space.
To provide further perspective, one CO2Meter customer located in North Carolina focuses on their mission towards elevating equipment performance and providing data analysis to ensure customers gain the most out of the equipment their businesses rely on. A specific project this company inquired, called upon a need for gaining real-time CO2 measurements to purposely structure a smart technology build.
The company utilized CozIR®-A 10,000ppm CO2 Sensors due to their compact design, low power consumption, and easy integration within their application. The project resulted in tremendous success due to the CO2 sensing data and there are now plans for continued projects.
Outdoor Air Quality Environments
For those that are interested in gaining further analysis and monitoring for Carbon Dioxide (CO2) in outdoor air environments, there are additional solutions available upon request. As air pollution is a continual major environmental topic of concern in reducing air pollution levels, carbon dioxide can be monitored by sensing technologies to control and maintain a specific area. It is possible to measure each polluting substance one by one and dedicated sensors are usually the sought-after solution.
For CO2 outdoor applications, any GSS ambient sensor solution can be utilized if it is protected in a very specific enclosure with temperature constraints. GSS CO2 Sensors are known to be reliable and accurate, maintenance free, and the life expectancy is greater than 15 years. Most customers who are interested in outdoor conditions are concerned with substances not only surrounding Carbon Dioxide (CO2), but Nitrogen Dioxide, Hydrocarbons, Carbon Monoxide, and Particles are also often considered.
The Future for CO2 Sensing in Indoor Air Quality
Emerging trends around CO2 monitoring and sensing solutions will only continue to emerge as air quality serves a significant topic towards improving the health and well-being of individuals across the globe. For years, manufacturers of high-end gas sensing technologies all produced sensors based on different materials such as photoacoustic spectroscopy; whereas today solutions are becoming further and further optimized in terms of compact size, speed, durability, accuracy, power consumption and crafted with special designs around specific OEM integration.
While poor indoor air quality, air pollution, and airborne illnesses all are consistently ranked as risks to public health; these issues will continue to go unnoticed and the need for proper monitoring and technologies to mitigate these issues will be critical.
The EPA concludes that poor indoor air quality affects 33% to 50% of commercial buildings just in the U.S. alone and is responsible for 10 million lost workdays a year.
With the ability to easily measure CO2 concentrations with CO2 sensors throughout a variety of indoor occupant spaces, individuals can start to understand what “good” air quality means and achieve a healthier indoor environment with contaminants controlled, once and for all.
GSS and CO2Meter Sensing Solutions Partners
The partnership between Gas Sensing Solutions and CO2Meter has a unique combination of attributes; a wealth of applicational insight; gas sensing expertise; and expert product knowledge, particularly in the indoor air quality (IAQ) market. We understand the importance of providing advice on not only what product fits the customer’s needs but how to get the best out of the product in a real-world environment.
Headquartered in the UK, Gas Sensing Solutions is a global leader in solid state Non-Dispersive Infra-Red (NDIR) LED based gas sensors. Uniquely, the LEDs and companion photo-detectors are manufactured in-house on molecular beam epitaxy (MBE) machines and used in all its patented NDIR diffusion CO2 sensors.