Key ideas from James Nestor

• Indoor CO2 levels at 1,500 parts per million can reduce cognitive test scores by 50% compared to outdoor levels of 425 ppm
• Commercial airplane cabins consistently measure above 2,500 parts per million CO2, causing drowsiness and post-flight fatigue
• LEED-certified and green-certified hotels often have the worst air quality due to recirculating air to save on heating and cooling costs
• Aranet 4 is the most accurate consumer CO2 monitor after testing 10 different devices against professional equipment
• Modern hotels have sealed windows to reduce maintenance costs, with heating and cooling accounting for 50% of operational expenses
• 30 to 40 years of government studies document cognitive impairment starting at 1,500 ppm and severe disabilities at 5,000 ppm