<Tr> <Td> Nitrogen </Td> <Td> </Td> <Td> 780,840 </Td> <Td> 78.084 </Td> </Tr> <Tr> <Td> Oxygen </Td> <Td> O </Td> <Td> 209,460 </Td> <Td> 20.946 </Td> </Tr> <Tr> <Td> Argon </Td> <Td> Ar </Td> <Td> 9,340 </Td> <Td> 0.9340 </Td> </Tr> <Tr> <Td> Carbon dioxide </Td> <Td> CO </Td> <Td> 400 </Td> <Td> 0.04 </Td> </Tr>

In which to earth regions is oxygen the second most abundant element by volume