the most abundant element in the air
we breathe, is essential to plant and
Historically, this airborne compound has persisted in a state of equilibrium
as part of a
embracing air, water, plants, animals, and soils.
human inputs from electric power generation, industrial activity, transportation, and agriculture
have disrupted this balance.
These sources have released unprecedented quantities of nitrogen
and related compounds to the environment in the past 50 years.
Other than nitrogen gas (N
two primary categories into which most nitrogen compounds fall are reduced nitrogen, typically
dominated by ammonia species (e.g., NH
), and oxidized nitrogen, composed primarily
nitrogen oxides (NO
Of these two categories of nitrogen compounds, oxidized nitrogen sources
are subject to a variety of regulations that limit emissions.
On the other hand, sources of reduced
nitrogen remain largely unregulated.
While this document discusses certain sources and issues with
regard to reduced nitrogen, it focuses primarily on atmospheric emissions, deposition, and impacts
of oxidized nitrogen (NO
Nitrogen emissions can affect human health in various ways.
Nitrogen dioxide (NO
) is irritating
to human lungs, and aids in the formation of
These airborne byproducts
of nitrogen emissions can cause premature mortality and chronic respiratory illness such as bron-
chitis or asthma, as well as aggravate existing respiratory illness.
While less directly linked to atmo-
contamination of drinking water supplies, largely from agricultural sources,
can result in
or Blue Baby Syndrome.