exists and is an alternate of . Carbon dioxide is denser than air. The density of carbon dioxide is 1,977 g/L at 0 0C and standard pressure. The density of air (the so called International Standard Atmosphere) is 1,225 g/L. Carbon dioxide is denser than air. <br /> The density of carbon dioxide is 1,977 g/L at 0 0C and standard pressure. <br /> The density of air (the so called International Standard Atmosphere) is 1,225 g/L.