Are you trying to decide whether to get rid of your cat, or a spouse who smokes?
Hi, I stand corrected. Was watching one of those sort of horridly-fascinating shows last night on TV that is about hoarders, except this one is about pet hoarders. They visited a couple's house who had 24 cats. The vet who was talking to the couple and she went into the room where the catboxes were, and commented on the smell, and she had handheld meter that she set down on the floor. It measured ammonia in the air. OSHA has limits of something like 25 ppm for people working in industry, apparently over that amount of ammonia in the air is bad for the lungs. As they were talking, the meter went over 25, then over 40, then over 60, then I think it stopped in the 70s or 80s. And the people were all standing and talking in the room, so it is not like they would automatically keel over or anything. But the vet explained that the body is less able to get enough oxygen into the bloodstream when it is breathing this much ammonia. So, although it won't give you cancer like secondhand smoke will, it could be a very serious issue for asthmatics or people with any kind of immune system challenge, and it seems like it could give you anemia if you are unable to get enough oxygen in the blood. The couple was wanting to have a baby, and the vet was concerned the baby would have birth defects if exposed to this kind of ammonia loading. It was pretty serious stuff.
No, but being able to smell it that strongly suggests the possibility that there is too much cat and not enough clean. Possible contact with feces, urine, parasites or dirty litter can give a person one or another physical problems. However, secondhand smoke can kill a person, and even the worst of contact with catboxes does not do that.