Ammonia, chemical symbol NH3, can take the form of a strong smelling liquid or gas. Most popularly, consumer and commercial products use the alkaline substance to clean grime or fertilize crops. Even in low concentrations, inhaling ammonia or getting the solution on your skin can cause burning, fainting, or death, so always use caution when handling this chemical.

Ammonia has one nitrogen atom and three hydrogen atoms tightly bonded. A tiny amount of ammonia forms when organic matter decomposes, so the gas can be found naturally in our atmosphere. However, we get most of our ammonia through artificial means by bonding the four atoms together by sheer force. Then the gas can be pressurized to form a liquid for easy distribution to manufacturing plants.

As a gas, ammonia is lighter than air, so it won't pool indoors like other dangerous gases, such as propane. While it has a very pungent, distinctive odor, it's clear and difficult to combust unless highly concentrated. This makes ammonia safer than other chemicals for household use, as most people will recognize the smell and leave a toxic area to prevent fainting.

Since ammonia gets easily incorporated into water as a solution, it's used in many cleaners. You probably have window sprays, oven foam, toilet bowl cleansers, wax removers, or countertop sprays among your household cleaners that contain around 5-10% ammonia. Never mix different cleaners in the same application. For example, ammonia and bleach form a very dangerous gas, called chloramine, that shouldn't be inhaled.

Commercial cleansers, with 25-30% ammonia, are extremely dangerous due to their corrosivity. Under careful oversight, liquid ammonia is also used to etch metal like aluminum and copper, refrigerate rooms or trucks, and dissolve other elements in chemistry labs. Most of the ammonia we produce goes to fertilizing crops by providing absorbable nitrogen to plants. Manufacturers of plastics, pesticides, and dyes use the liquid at some point in their synthesizing process.

In its earliest application, cotton balls were soaked in ammonia and sealed inside tiny bottles. People who fainted were revived with a whiff of the strong smell. This was generally safe, as long as it wasn't too frequent. Today we aren't likely to find smelling salts inside a medicine cupboard unless they are antiques.