It comes from the decay of matter without the presence of oxygen. Primary sources include wetlands, rice paddies, animal digestive processes, fossil fuel extraction, and decaying garbage. It is destroyed primarily through chemical reactions with other gases in the atmosphere. Nitrous oxides . Soils and oceans are the primary natural sources, while humans contribute to nitrous oxide emissions through soil cultivation and use of nitrogen fertilizers, nylon production, and the burning of organic material and fossil fuels.
Ozone exists naturally in the lower atmosphere in minute quantities.
It is also produced in the lower atmosphere from a reaction involving several human-produced pollutants and sunlight. They are some of the most potent greenhouse gases of all. Over the past 200 years methane concentrations have more than doubled. And some greenhouse gases, such as halo-carbons, have come into existence only in the last 100 years. Scientific theory predicts that they will.