A. Oxygen (O2)
B. Nitrogen (N2)
C. Carbon dioxide (CO2)
D. Ozone (O3)
E. Chlorofluorocarbons (CFCs)
The atmosphere contains many gases, most in small amounts, including some pollutants and greenhouse gases. The most abundant gas in the atmosphere is nitrogen, with oxygen second. Argon, an inert gas, is the third most abundant gas in the atmosphere.
