Indoor air quality, particularly CO2 levels, significantly impacts sleep quality and overall health. Human respiration and tightly sealed, energy-efficient buildings can lead to CO2 buildup in bedrooms, reducing oxygen availability and causing sleep disturbances. Studies show elevated CO2 levels lead to poorer sleep and reduced cognitive performance. Managing indoor CO2 through improved ventilation, monitoring, and HVAC maintenance is essential for restful sleep and well-being. Additionally, nighttime outdoor CO2 levels, especially in urban areas, can further affect indoor air quality.