I have had to use the nebulizer for two weeks following having this congested cough twice since October. Quoting: Anonymous Coward 14091728
The WEIRD thing is this; Had a metallic smell when breathing......odd.
The way smell works is that tiny molecules in your nose impact on the olfactory nerve. Your mucus is the medium (the sea if you will) that allows those molecules to travel in. The sea is constantly (every ten minutes) replaced. Surprised? It's a mundane but vital aspect of sensation.
When the respiratory tract is clogged or cracked or both, then it impacts smell. The molecules can't travel and materials within the "sea" may be deposited which interfere with the sensation of smell.
When you use a vaporizer or nebulizer (better kind of vaporizer with medicine in it), then moisture and or moisture and medicine allows clearing of the sea. This allows a relaxation of the opening so more air is passed through, it is wetter, the mucus clears, and your sense of smell improves.
Iron is a component of blood. Most likely since the sea(mucus) in which molecules travel to the olfacory nerve cells also has cracked irritated areas and dried blood in it, you're smelling that.
By the way, those olfactory nerves are a part of the Limbic system of your brain which invokes memory. Because of that, a smell can trigger a memory like smelling a perfume, an orange, warm cookies, etc.
One actually can use that to help prepare for exams. Another use might be to help Alzheimer or dementia patients. Demenitia might come from 11 different kinds of illnesses.