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.