Last week we offered some cliff notes on ammonia/what can be expected/what is not normal, etc.. On another forum I expanded our explanation we offer to our customers, so I am going to do the same his week
Ammonia burn/chafing is never acceptable, it is something we work with many customers to fix, usually by 1)fixing the wash routine or 2)increasing absorbency/breatheability depending on why the child is sensitive to the urine.
Ammonia isn’t present in urine until it leaves the body and meets air, the Urea that it is converted to internally is sterile until oxygen will start to convert it to ammonia (unless of course you have a bladder infection or UTI which isn’t the norm either). There are lots of factors that can cause that “ammonia” smell, some will never encounter it at all unless these factors are in play. Heavy wetters will be more prone to the odor, if you have had a light wetter versus a heavy wetter, you know the difference between the volumes. When you start adding half an ounce of urine to each diaper change, or more, you are really increasing the urea output. Toddler urine is more complicated as well, more going into it, more coming out-LOL
Additionally, if your baby pees when you put them down and it is a big one, you are getting several hours of a headstart on this whole process, so the odors will be much stronger. Imagine peeing on a tee shirt (fitted/prefolds), wrapping it in a plastic bag (cover) then leaving it for 8 hours, it would stink to high heaven when you opened the bag, on the flip side, if your had your 2 month old pee in a little tee shirt and did the same thing for 3 hours, the stench wouldn’t be nearly as much, hence the volume/concentration/age factors.
For the pail, it can vary based on lots of things, if you keep an open pail in a broom closet and wash toddler diapers every 3-4 days, your odors will be very different from a closed pail in a larger ventilated room washing every 1-2 days. Clean diapers will still do this in pails, it doesn’t matter how clean they are going in, if you have the right combination of volume and age in urine, it can produce the same effect.
Nothing that harms a baby’s skin is ever normal, and needs to be corrected. For some babies increasing absorbency does the trick, breaking down the concentration of urea leaving the body makes it less volatile on the skin. For some, they need more breatheable options, since air still gets into PUL diapers you never have an airtight diapering system, but for some babies the extra air flow to their skin is what it needs to tolerate that old urine breathing back onto their skin.
For some babies, you need to explore eczema and other skin sensitivities, if you have skin that is already compromised to begin with, adding urine breathing onto it for 8+ hours is too much. Middle of the night changes, eczema ointments,other options can help. For “yeasty” babies cornstarch is great as a preventative measure (not during an outbreak, as it will feed the yeast, but on healed skin to prevent it is great), plus lots of air flow/naked time so the fungus has a hard time growing without the moist and dark conditions.
We relay this to our customers who have perfectly fresh diapers out of the dryer (meaning nothing bacterial is left behind from feces), and the diapers do not smell of stale urine when freshly peed in (indicates buildup and need to be stripped), and the only time they smell the ammonia odors, or “strong urine” odors is in the pail when they lift the lid to toss in a newly soiled diaper, or the morning diaper on from 8 hours prior.

Some fun urine links-LOL:

http://www.mayoclinic.com/health/urine-odor/MY00378

http://sxxz.blogspot.com/2006/07/why-is-urine-yellow.html