What are Acceptable CO2 Levels in Commercial Buildings?
Thursday, 21st April 2022
While sustained exposure to carbon dioxide at high levels (above 2000 ppm) can cause symptoms such as headaches, sweating, and shortness of breath, the research on the direct health impact of lower levels of CO2 remains mixed.
But aside from the gas’s direct effects, what we do know is that CO2 can be used as an indirect measure of ventilation, viral risk, and indoor air quality (IAQ).
So, what is an acceptable level of CO2 in commercial buildings? We explore what you need to know.
Why is monitoring indoor CO2 levels important?
Monitoring indoor CO2 matters primarily for what it tells you about other air pollutants. CO2 as an effective indirect measure of indoor air quality (IAQ) in general. But further, it is a crucial indicator of the risk of viral transmission too.
Let’s explore these two factors in detail:
1. CO2 is an indicator of indoor air quality
Indoor carbon dioxide levels can vary widely, ranging from a few hundred ppm to 1000 ppm and above. They are influenced by:
The number of people using a room
Occupancy time
The size of an indoor space
The quantity of outdoor air being ventilated and the quality of that outdoor air
Pollutants from nearby combustion, e.g. from vehicle exhausts near air vents.
Since CO2 is a product of combustion, its levels can be raised by things such as vehicle exhausts and furnaces. Combustion from these sources can also generate other products, such as carbon monoxide (CO) and particulate matter (PM), which both have serious health effects.
Other indoor air pollutants, such as Volatile Organic Compounds (VOCs), emitted by some furnishings and building materials, can build up in poorly ventilated buildings without adequate fresh air. So although relatively high levels of CO2 may not cause health problems directly, they can be viewed as one indicator of poor ventilation, and, as consequence, lowered indoor air quality.
The average American spends 90% of their time indoors and research has found that stuffy, poorly ventilated buildings negatively affect employee productivity. This has a material impact on businesses. For example, the Centers for Disease Control’s National Institute for Occupational Safety and Health (CDC) quote the cost of poor indoor environmental quality to US businesses as in the range of $20 to $70 billion per year.
2. CO2 is a measure of indoor ventilation and viral risk
Since carbon dioxide is a natural product of human respiration, indoor occupants are its main contributors. As a result, as we’ve just alluded, high concentrations of indoor CO2 can be used as measures of occupancy and ventilation rate.
But good ventilation is crucial in mitigating the spread of viral infection by aerogenic transmission (infection by small particles that hang in the air), so much so that changes are being made at the national level. In the UK for example, a campaign is underway to monitor CO2 levels in classrooms across the UK to help lower viral transmission risk.
And, from June 2022, it will be mandatory for all office buildings to have CO2 monitors.
What are acceptable CO2 levels in buildings?
What are seen as acceptable CO2 levels typically vary from country to country.
For example, in the UK, the government has agreed to a set of standards for acceptable CO2 levels in indoor spaces:
800 ppm or below indicates that an indoor space is likely to be well ventilated and has acceptable indoor air quality.
Consistent levels of 1500 ppm and above indicate that the room is badly ventilated. In these cases, measures should be taken to improve ventilation.
Guidelines can differ according to nation. The United States Department of Labor’s Occupational Safety and Health Administration (OSHA), for example, has set a permissible exposure limit of 5000 ppm of CO2 as a time-weighted average over 8 hours. And, according to ASHRAE, the American Society of Heating, Refrigerating and Air Conditioning Engineers, levels of indoor carbon dioxide should be below 700 ppm.
Many nations, including Japan, Korea, Portugal, France and Norway, have set 1000 ppm of CO2 as the standard for specific indoor environments, including school and office buildings.
Indoor pollution directives tend to be set out as guidelines, rather than enforceable laws. However, employers in the UK are still responsible for keeping their employees safe at work.
What are the current challenges in maintaining CO2 levels in buildings?
In the UK, from June 2022, CO2 monitors will be mandatory in all office buildings and new standards for recirculating ventilation will be introduced. This is part of new revisions to Building Regulations which are intended to improve ventilation and IAQ in commercial and residential buildings.
This move underlines the importance of having robust measures in place to monitor, report and take action on levels of CO2. But doing so isn’t always so easy, especially in a commercial setting.
Here are some of the challenges of maintaining good indoor air quality:
Monitoring. Traditionally, air quality monitoring is performed with sporadic, one-off air quality checks. But these legacy technologies cannot provide your business with the wealth of data needed to properly manage air quality in your buildings. These older technologies tend to need manual, on-site management and are time-consuming and costly to install.
Reporting. Research carried out for our Healthy Buildings report found that 61% of employees said improved air quality would make them feel safer after the pandemic. We know that demonstrating optimum air quality is paramount for employee health and confidence in returning to the workplace. But doing so isn’t always easy.
Taking action. It’s important that the source, not just the symptoms, of poor IAQ is tackled. Businesses need site-wide and historical data to tackle poor IAQ in conjunction with other healthy building indicators, such as occupancy levels.
An effective strategy to optimise IAQ
At Infogrid, we’ve designed an integrated, smart, and scalable system so that you can ensure the IAQ in your building is at the optimal level, 24/7. Effective and automated CO2 monitoring is part and parcel of this.
Here’s what makes the difference:
A smart system of sensors. Our best-in-class IoT air quality sensors are part of our Healthy Building system, a network of automated sensors that are quick to install and can scale to fit any workplace. Once installed, our sensors are fully automated and zero-maintenance.
Access IAQ data in real-time and share effortlessly. Unlike sporadic checks, the Infogrid IAQ system monitors 24/7 and feeds automatically to our dashboard. With our advanced AI, whole-site data—including detailed real-time information on HVAC and ventilation systems—is visualised and interpreted intuitively, allowing you to report on air quality efficiently and effectively.
Be proactive about IAQ. Good IAQ is achieved by controlling a range of factors. Our sensors monitor key pollutants including radon gas, VOCs, and PM as well as other indicators of indoor air quality: CO2, ventilation rates, relative humidity, air pressure, temperature and light levels. With our IAQ system, you can analyse site-wide and historical data so you can make smart, evidenced-based decisions for your business.
Experience real benefits of improved IAQ with Infogrid
Taking a smart, wide-ranging and proactive approach to IAQ yields serious benefits. Here are just some of the benefits you can expect from using our integrated system of automated IAQ sensors:
A significant reduction in viral risk. Reduce employee absences by 30% and reduce viral transmission risk by 80%.
Optimise office space in real-time. Use CO2 monitoring in conjunction with occupancy data to optimise indoor IAQ for all occupants, at all times.
Increase employee happiness and productivity. 70% of employees want better air quality. Optimise your IAQ and see a 50% increase in productivity.
Reduce the need for building maintenance. Ensure humidity levels are correct to reduce levels of mould and mildew and decrease the frequency of equipment breakdowns.
Don’t just settle for acceptable levels of CO2, use our smart, integrated and automated system to optimise IAQ for your whole workforce, and reap the benefits.
Try out our demo, here.
