Injected into the exhaust stream, the solution's ammonia reacts in the de-NOx catalyzer to form nitrogen and water vapor.

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The hazardous compounds are: two forms of hydrazine, nitrogen tetroxide and a pure form of ammonia.

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Nitrogen oxides contribute to haze and form small particles that make people sick and even kill them.

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This will eventually wash through to the river, as will nitrogen applied to those fields in the form of fertilisers.

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He's known for performing "cryosurgery"--a form of surgery that uses liquid nitrogen or nitrous oxide to freeze off cancerous tumors rather than cutting them out or amputating the host limb.

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They hired a scientist to come up with a formulation of chemicals that delivered nitrogen, potassium and phosphorus in highly water-soluble form, so that an impatient gardener could give plants an instant shot to the leaves, so to speak.

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