Why doesn't the Nitrous Oxide in the air make us funny?

The chemical formula for nitrous oxide is N2O. Actually, the elements that make up N2O, nitrogen and oxygen, are the two most abundant elements in the earth's atmosphere. Nearly 99 percent of the earth's atmosphere is nitrogen and oxygen. In the atmosphere, both oxygen and nitrogen exist in their natural ans most stable elemental states; in other words, atmospheric oxygen exists as a molecule of two oxygen atoms bonded together, O2, and atmospheric nitrogen exists as a molecule of two nitrogen atoms bonded together, N2. O2 and N2 are very stable molecules and don't usually break up to form a compound like N2O. In fact, the N2O that dentist use as laughing gas is made by a completely differnt chemical reaction. So, naturally, there is very little N2O in the atmosphere (about 0.000003 percent), but due mostly to human activity, it is actually increasing by about 0.3 percent every year. Even so, there is not enough N2O in the atmosphere to make us giggly. (Laughing gas is actually 50 percent O2 and 50 percent N2O; a very concentrated mixture compared to the air we breathe everyday.)

So, if there isn't enough N2O in the atmosphere to make us funny, why is it considered a problem? N2O is extremely efficient at warming up the atmosphere. In fact, one molecule of N2O has 200 to 300 times the greenhouse warming effect of CO2, the primary greenhouse gas. So, it only takes a little N2O to cause greenhouse warming, but it takes a whole lot to make us funny.

For more information about nitrous oxide and other greenhouse gases, you might try some of these web sites:

Greenhouse Gas Mixing Ratios
The increase in greenhouse gases over time and projected through the year 2000.

Ledley, T.S., E.T. Sundquist, S.E. Schwartz, D.K. Hall, J.D. Fellows, and T.L. Killeen, Climate change and greenhouse gases, Eos, 80 (39), 453-474, 1999.

Still have questions about nitrous oxide in the atmosphere? Ask the GCMD science staff at GCMD User Support.

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