Posts Tagged ‘airborne0mg’
William F. Wells – Wikipedia
March 7, 2025Airborne | Carl Zimmer
March 2, 2025The Word “Quarantine” Comes from the Italian Word “Forty Days” | Office for Science and Society – McGill University
March 2, 2025Darwin’s Dust | The Dispersal of Darwin
March 2, 2025https://thedispersalofdarwin.wordpress.com/2009/01/19/darwins-dust/ Darwin’s sighting of red dust, which he gave to Ehrenberg
Ventilation causing an average CO2 concentration of 1,000 ppm negatively affects sleep: A field-lab study on healthy young people – ScienceDirect
March 2, 2025QT:{{”
Some current standards for ventilation set the maximum recommended limits for indoor CO2 concentration [14]; traditionally the
concentration of 1,000 ppm CO2 has been used since Pettenkofer [15] proposed that it is a marker of unacceptable indoor air quality, CO2 being considered as benign. Studies have shown that ventilation rates in bedrooms often result in higher levels of CO2 that suggest poor air quality and insufficient ventilation rates [[16], [17], [18], [19], [20], [21]].
While Pettenkofer proposed 1,000 ppm, he additionally recommended that the maximum CO2 concentration in bedrooms for achieving good air quality should be around 700 ppm; in his estimates he assumed an outdoor CO2 level of 500 ppm [15]. A recent summary of papers published in peer-reviewed journals linked bedroom ventilation with its effects on sleep quality [14]. The conclusion was that sleep quality was not affected when the average CO2 level resulted by ventilation in bedrooms had been below 750 ppm (e.g., Refs. [10,22]), while average levels above 1,150 ppm were consistently found to cause disruption to sleep (e.g., Refs. [11,13,23]). Average levels above 2,600 ppm were observed to reduce next-day performance [23]. No conclusive results were obtained regarding the effects on sleep quality when average CO2 levels were between 750 ppm and 1,150 ppm. In a recent field study reported by Fan et al. [12], it was not possible to determine the minimum ventilation rate for sleep quality even though three ventilation rates were examined because insufficient data reduced the sensitivity of the experiment. Building standards in many countries (e.g., Canada [24] and China [25]) stipulate minimum ventilation rates that result in a CO2 concentration of 1,000 ppm. The main reason is to achieve good perceived air quality. Few standards stipulate minimum bedroom ventilation separately and there are no studies to confirm whether 1,000 ppm is an adequate recommendation for sleeping environments, as discussed above.
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An absolute CO2 concentration of 0.1 % or 1000 ppm is since then used around the world as “Pettenkofer-zahl” (Pettenkofer number).
The father of hygiene – LMU Munich
March 2, 2025https://www.lmu.de/en/newsroom/news-overview/news/the-father-of-hygiene.html
To prove his hypothesis, Max von Pettenkofer drank a suspension of cholera bacteria. He survived the cholera cocktail, and his research on the impact of hygiene on health would revolutionize medicine and public health.
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