General Population Exposure Limits

Emergency Response Planning Guidelines (AIHA)1 - ERPG: Maximum airborne concentration below which it is believed that nearly all individuals could be exposed for up to 1 hour without:

  1. experiencing other than mild transient adverse health effects or perceiving a clearly defined objectionable odor (ERPG-1).
  2. experiencing or developing irreversible or other serious health effects or symptoms that could impair an individual s ability to take protective action (ERPG-2).
  3. experiencing or developing life-threatening health effects (ERPG-3).

Short-term Public Emergency Guidance Level (NRC) - SPEGL: An acceptable concentration for unpredicted, single, short-term exposure of the general public in emergency situations. May be developed for different exposure periods. (eg., 1, 2, 4, 8, 16, 24 hours)

Acute Exposure Guidelines (EPA NAC/AEGL) - AEGL: Proposed short-term threshold or ceiling exposure value intended for the protection of the general public, including susceptible or sensitive individuals but not those who are hypersusceptible or hypersensitive. Represents the airborne concentration of a substance at or above which it is predicted that the general population (as defined above) could experience:

  1. notable discomfort (AEGL-1),
  2. irreversible or other serious, long-lasting effects or impaired ability to escape (AEGL-2)
  3. life-threatening effects or death (AEGL-3). Developed for four exposure periods: 30 minutes, and 1, 4 , and 8 hours. Synonymous with the NAS4 term,