Table 2.

Primary diagnoses, histology scores (mean ± 1 SD), and ammonia exposure (ppm; mean ± 1 SD)

Primary diagnosis	n	Histology score	Total ammonia exposure	Daily ammonia exposure	No. of days on which ammonia levels were ≥ 25 ppm
Rhinitis	19	12.0 ± 2.79a	3288 ± 1409b	181 ± 67b	18 ± 2.79
Necrosis of olfactory epithelium	9	6.0 ± 1.58a	1436 ± 768b	93 ± 66b	16 ± 3.46
Degeneration of respiratory or transitional epithelium (or both)	11	3.0 ± 1.0a	730 ± 510	52 ± 28b	13 ± 4.1
Ammonia exposure and no lesions	9	0.22 ± 0.44	182 ± 57	32 ± 18	6 ± 3.26
Exposure to 0 to 10 ppm ammonia and no lesions	17	0.88 ± 1.05	0 ± 0	0 ± 0	0 ± 0

^aScore significantly (P ≤ 0.05) increased compared with those for ammonia exposure and no lesions and exposure to 1 to 10 ppm ammonia and no lesions.

^bExposure level significantly (P ≤ 0.05) increased compared with those for ammonia exposure and no lesions and exposure to 1 to 10 ppm ammonia and no lesions.