Air has a very low density compared to many other substances. At room temperature (25 °C) and atmospheric pressure (1 atm), the density of air is approximately 0.001275 g/cm³ or 1.275 kg/m³. This means that one liter of air at sea level weighs approximately 1.275 grams. The density of air increases as the temperature decreases and decreases as the temperature increases. It also increases as the pressure increases and decreases as the pressure decreases.