How is Ozone Formed?

Ozone does not come from a single source, but is formed in the air through a complex series of reactions involving light and chemical precursors. Although we cannot simply shut down a single emission source and stop ozone, we can limit the amount of precursor chemicals that produce ozone in the atmosphere.

These chemicals are Nitrous Oxides (NOx) and Volatile Organic Compounds (VOCs), which come together in the presence of sunlight to form ozone. Both NOx and VOCs are produced from a variety of sources.

NOx may be produced by both natural and man-made sources, including agricultural activity, animal manure, sewage treatment, and burning fossil fuels. NOx is also produced naturally from a wide variety of biological sources in soil and water, particularly microbial action in wet tropical forests.

VOCs are also produced by a variety of sources including fossil fuel refining and combustion and thousands of industrial chemical products; however, they are also produced in large quantities by natural sources such as vegetation.