Figure 4
The graph is titled “PPM Level-School 1 over B”. The horizontal axis shows dates ranging from 08.02.2022 to 15.03.2022. The vertical axis is labeled “P P M (parts per million)” and ranges from 0 to 3,000 in increments of 1,000 units. A single continuous line represents the P P M levels over the given period. The line shows a repeated pattern of sharp spikes followed by rapid declines and longer flat segments. Most baseline values remain between approximately 400 and 600 parts per million. At multiple points across the timeline, the line rises steeply to peaks between approximately 1,800 and 2,800 parts per million, then drops quickly back to near baseline levels. These spikes occur frequently throughout the entire period, with clusters of peaks visible in early February, mid-February, late February, and early March. The highest visible peak occurs near the end of the time range, reaching close to 2,900 parts per million. Between spikes, the values stabilize around the lower range, forming extended low-level plateaus before the next sharp increase. Note: All numerical values are approximated.Measured CO2 levels (ppm) from Datalogger in School 1, zone B