Table 3.

Synopsis of short-term inhalation exposure levels^a

Severity Tier	Short-term inhalation exposure levels			ERPGb
	1	2	3	2	3
Key Study	Katz and Talbert (1930)	Zieve et al. (1974)c	Tansy et al. (1981)
Species	man	rat	rat
Adverse Effect	risk of nausea	coma	survival
POD Type	olfactory	BMCL10	BMCL05
POD Duration	none	15 min	4 h
POD (ppm)	1.9	47,409	25,895
Uncertainty Factor
LOAEL	N/A	N/A	N/A
interspecies	N/A	10	3
intraspecies	3	3	3
Modifying Factor	none	none	none
Total Factor	3	30	10
POD/TF (ppm)	0.6	1580	2590
Time Scaling	none	CPOD × (tPOD / t)1/n
		nS→L=2.89, nL→S=3.64		nS→L=1 nL→S=3
10 min	0.6	1800	4600d	1800	9100
30 min	0.6	1200e	4600	1300	6300
1 h	0.6	1000	3800	1000	5000
4 h	0.6	600	2600	250	1250
8 h	0.6	500	2000	125	625

^aConcentrations in ppm. Tier-2 and −3 levels were rounded to two significant figures.

^bShown for the purpose of comparison. ERPG is the maximum airborne concentration below which it is believed that nearly all individuals could be exposed for up to 1 h without experiencing or developing adverse health effects of specified severity (AIHA2014). These health effects are: for ERPG-1: mild, transient health effects or perception of a clearly defined objectionable odor; for ERPG-2: irreversible or other serious health effect or symptoms that could impair an individual’s ability to take protective actions; for ERPG-3: life-threatening health effects. Concentrations at exposure durations other than 1 h were extrapolated from the ERPGs using default UFs (NRC 2001). The extrapolated values are italicized.

^cSupplemented with data from Ljunggren and Norberg (1943) and Schoenig (1967b) studies.

^dAssigned at the level of 30 min exposure, following NAS recommendations (NRC 2001).

^eLevels derived by concentration-time extrapolation from shorter to longer durations are shown in bold