It can be dangerous since its concentrated form can be hazardous and caustic.
And not only do they smell, but they can irritate the skin. Ammonia is very caustic!
Hi, Have you ever colored your hair? No but home coloring had almost reached 2 billion in the US in 2011 and was expected to hit 2.2 billion in 2016. Wow that's a lot of money for hair coloring. Can you guess why I did my hair? The main cosmetic reasons for it would be covering gray or white hair, to get a more fashionable color or restoring one's original hair, so would it be one of those? Yes, the last one, I had some issues with my hair coloring and had to get it done to look like my old self again. Do you know who I went to for it? So it can be done at home or done professionally by someone like a hairdresser. Would it be by a hairdresser? Yeah, there was a nasty ammonia smell though, I don't know if it is dangerous or not though.
Although common in nature and in wide use, ammonia is both caustic and hazardous in its concentrated form.