Have you noticed that certain classrooms at UC Berkeley make you more tired? Have you ever sat in a classroom for hours and found it difficult to pay attention or even stay awake? This could be due to the air you are breathing. The lack of proper ventilation seen in many classrooms across the country can hinder student performance and increase the spread of disease.

On my first day of class in August, environmental health sciences associate adjunct professor Asa Bradman measured the carbon dioxide levels in Evans 10 and found that it was much higher than average. Many people breathing in a small space leads to a buildup of heat and carbon dioxide, especially in larger class sizes due to low rates of ventilation. Why is this concerning? Poor indoor air quality impairs cognitive abilities through the dilation of blood vessels in the brain, thus lowering neuronal activity.

You may have heard that carbon dioxide can negatively impact the environment and contribute to global warming. It also affects people indoors because as there is more carbon dioxide in the air, there is less room for oxygen to go into human brains. The average outdoor atmospheric concentration is about 400 parts per million, or ppm; however, indoor concentrations can go up to several thousand ppm. Adverse effects such as drowsiness can be seen once it reaches about 1,000 ppm, and other physical effects can begin at 2,000 ppm. In office buildings, carbon dioxide levels generally do not go over this threshold. In classrooms, however, concentrations frequently exceed 1,000 ppm.

According to the Lawrence Berkeley National Laboratory, 85% of California classrooms are underventilated. The lab also studied the association between productivity and carbon dioxide levels. Researchers exposed participants to concentrations ranging up to 2,500 ppm, an amount that is common in crowded spaces such as classrooms. The participants took a problem-solving test that measured productivity, and the results showed that the higher the carbon dioxide levels they were exposed to, the worse the test-takers did.

UC Berkeley is known for its historic architecture. In fact, most buildings were built in the late 1800s and the 1900s. You might have had a class in Evans Hall, which was built in 1971 or Dwinelle Hall, built in 1952. According to the National Center for Education Statistics, many school buildings were built in the 1960s to accommodate the surplus of baby boomers entering schools and were constructed with “energy-saving features like windows that could not be opened.” These features decreased costs to heat the buildings, but came with unintended repercussions such as classrooms with low air quality and above average carbon dioxide concentrations.

This is a widespread issue that impacts many public schools and universities in the United States. The National Center for Education Statistics reports that 30% of public K-12 schools in the United States have “reported heating systems, air conditioning systems, and ventilation systems to be in fair to poor condition.” A literature review by Berkeley Lab scientist William Fisk shows that the annual net costs to meet current carbon dioxide regulations would only range from a few dollars to an estimated $10 per person. To put these costs into perspective, “the energy and capital costs of increasing ventilation rates would be less than 0.1% of education spending.”

This demonstrates the need for increased ventilation, especially in classrooms that do not have windows or doors for fresh air. There is evidence indicating that not only can high ventilation rates raise students’ test scores and increase focus, but they can also lower the supply of contaminants, which in turn reduces respiratory disease rates. When possible, it would be helpful for professors to open a door or window to let fresh air in. Studies show that increasing outdoor air supply can inhibit the airborne transmission of common respiratory diseases such as influenza. More research needs to be done to analyze the impacts of ventilation on other highly contagious diseases such as COVID-19. Furthermore, we need increased real-time monitoring of carbon dioxide levels in our classrooms to better detect and correct ventilation problems. For instance, carbon dioxide sensors provide a visual warning signal when concentrations are elevated, which may help prompt window use to increase air flow.

By implementing carbon dioxide control, we can measure the amount of fresh air that is in a room based on its occupancy. Not only do sensors automatically regulate air delivery and monitor air quality through ventilation, but they have also been proven to cut energy costs and reduce greenhouse gas emissions. This can lower energy costs by about 60% as well as reduce wasted energy, which is a win-win situation. Carbon dioxide sensors have many advantages, especially air quality monitoring, which would have lasting positive effects on both students’ and professors’ health, focus and quality of life.