“… the UK Health and Safety Executive has defined safe CO2 limits for the workplace. The limit for long-term exposure is 0.5% (5,000 ppm) but for shorter encounters it is 2% [20,000 ppm]. Anything over that figure is regarded as a risk to human health.” Skeptical Science, advertised as “getting skeptical about global warming skepticism,” … Continue reading Why CO2 is Not a Pollutant