Have you ever been in a room with lots of people and not great ventilation. Or even a room with normal ventilation. You may be cognitively impaired due to elevated levels of CO2 once considered safe now thought enough to make you a little dumb. 600ppm is now thought too much, but “there are plenty of buildings where you could easily see 2,500 ppm of CO2 — or close to it — even with ventilation designs that are fully compliant with current standards.. classrooms frequently exceed 1,000ppm." [more inside]
Why do we yawn? There are many theories. New research suggests it cools the brain.. a cooler brain is more alert.