What effect does burning leaves have to do with the air we breathe?

I hear a lot of people argue back and forth if burning leaves is bad for you. I think it is since it gives off that odor that makes it hard to breath and with the heat from the flames just makes a uncomfortable situation to be in. While looking for some answers that I had about burning leaves I found this website that says it all. In the website it tells you that when burning leaves it gives off carbon monoxide, and other chemicals that can result in affecting people with allergies. Instead of burning leaves you can get rid of them in different ways. You can mulch leaves which will give the soil excellent nutrients, or you can even bag your leaves for collection. If you burn your leaves it is fine just look at that website and look what your polluting the air with, since those harmful chemicals in the smoke are not good for anyone.