The Study of Co₂ Concentration in A Classroom During The Covid-19 Safety Measures

Abstract

The COVID-19 crisis has affected the process of how the study procedures are organized at schools in Latvia. Three different options were available for the school to choose from. However, most schools have opted for option A which states that the classes are organized face-to-face but various safety measures must be ensured. Each class or group is equated to a closed set where there are no distance requirements. In turn, the distance between the classes must be observed. This means that students stay in the same class all day and are accompanied by teachers of the respective classes. This can lead to improper ventilation as for most of the schools in Latvia it is organized through the opening of windows. To test this, measurements of CO2 concentration were done in a classroom Secondary School in Daugavpils. The results showed that the CO2 concentration was very high and often reached and exceeded the maximum measuring capacity of the device - 4000 ppm. It indicates that following the special safety procedures cause a negative effect on IAQ as the classrooms are not properly ventilated. This can lead to a drop in the performance of pupils as well as stimulate the transmission of other infectious diseases. Further measurements are necessary to gather data from different schools and best practices must be found.

Ventilation conditions and their influence on thermal comfort in examination classrooms in times of COVID-19. A case study in a Spanish area with Mediterranean climate

“…This showed that the effect of this stop was not significant on the IAQ during the test. The same effect was also found in the work of Zemitis et al (2021) . In relation to air renewals, these were 9.01 with a clean air supply per occupant of 42.39 l/s per person (values well above the minimum recommendations to guarantee adequate air quality and minimise COVID-19 infections) ( Allen et al, 2020 ; Minguillón et al, 2020 ).…”

“…These values were very similar to those obtained in this work ( Villanueva et al, 2021 ). However, in the case of the research carried out in schools in Switzerland and Latvia, CO 2 concentration was much higher, with average values of around 2000 ppm, and consequently air renewal in both cases was insufficient ( Vassella et al, 2021 ; Zemitis et al, 2021 ). Comparing CO 2 concentrations, it can be verified that ventilation conditions in the present study are significantly better than those reported in most of the existing literature.…”

“…In this study, CO 2 concentration levels significantly exceeding 1000 ppm were obtained in all the classrooms studied. The average concentration was approximately 2380 ppm and even reached absolute maximum levels of 4424 ppm ( Zemitis et al, 2021 ). Vassella et al developed an intervention study to verify whether the recommended indoor air quality objectives can be achieved by following reasonable ventilation regimes that are also suitable for countries with cold winters.…”

The Required Amount of Ventilation Air for the Classroom and the Possibility of Air Infiltration through the Windows

“…As determined by the European branch of the World Health Organization [35] and the American Society of Heating, Refrigeration and Air-conditioning Engineers [47], the permissible concentration of carbon dioxide in closed spaces is 1000 ppm (0.1%), which is a requirement of the so-called hygienic minimum. This acceptable limit is often exceeded, reaching (in the classrooms) such values as high as 4000 ppm [28,36,[48][49][50][51]. The presented phenomena are very common in education buildings with natural (gravity) ventilation systems dominant in Poland, as well as in the countries with similar climate.…”

The Control of Metabolic CO2 in Public Transport as a Strategy to Reduce the Transmission of Respiratory Infectious Diseases

“…In the pre-pandemic period, CO 2 measurement helped improve academic performance in schools and colleges [ 24 ] and, sporadically, control infectious diseases [ 25 ]. Due to the COVID-19 pandemic, CO 2 measurement has become one of the preferred preventive strategies to reduce the risk of contagion by aerosols [ 22 , 26 , 27 ]. The direct measurement of aerosols to determine the risk of contagion by SARS-CoV-2 is highly complex and expensive since it requires highly specialized equipment.…”