ESS101C
Prof.
Jin-Yi Yu
The Odd Nitrogen Cycle
qN2O: from Earth’s surface, where it is produced by microbial activity in soil and in the
ocean.
è In the stratosphere, some of N2O reacts to form NO, the rest is photolyzed back to N2 and
O2.
èThe NO so produced participates in the ozone-destroying nitrogen
catalytic
cycle.
èOnce for a while, the resulting NO2 molecule interacts with a hydroxyl radical (OH), producing
nitric
acid (HNO3).
èNitric Acid (HNO3) then diffuses
down into the troposphere and dissolves into rain.
(from The Earth System)
from UV photolysis of ozone