Nitrogen oxides and NO2 primary composition in earth’s atmosphere

Kole Lutz — 2025-12-31

Humans believed Earth was 78% nitrogen (N₂) and 21% oxygen (O₂) until the 2020s. Based on data collected by balloons and satellites since the 1980s, evidence suggests that Earth's atmosphere is composed of complex molecules such as nitrogen dioxide (NO₂) with polar bent molecular structures, similar to water (H₂O). Although nitrogen-oxygen mixing ratios have been recorded for over 50 years, they have often been overlooked in studies of redox reactions, biological systems, and nitrogen-fixing bacteria. Microorganisms, including bacteria in oceans and soils, release nitrous oxides, NO₂, NO, and N₂O, which are abundant in these environments. Nitric oxide (NO) is also among the most prevalent molecules in biological systems; experiments indicate that NO₂ and NO diffuse rapidly across cell membranes. Measurements at altitudes of 10-12 km show a ratio of 1 NO to 2-6 times NO₂, with air density estimates indicating 300-400% more NO₂ compared to NO at the surface. Near the surface, the ratio is approximately ₂:1 NO, similar to the historically accepted 78% nitrogen measurements. This data suggests that the air density of NO₂ is less than 2.05257 g/L or kg/m³, which is about 68% heavier than the standard air density of 1.19 g/L. Ongoing research enhances data models related to atmospheric composition, aerodynamics, climate change, biological processes, materials science, surface redox reactions, and planetary studies.

Journal of Atmosphere

Nitrogen oxides and NO2 primary composition in earth’s atmosphere