Emission
noun, verbal noun, の adjective
Things that are emitted and then exit are, well, emissions.
はいしゅつ
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
植物は二酸化炭素を吸収し、酸素を排出します。
Plants absorb carbon dioxide and give off oxygen.