Final answer:
Short Term Exposure Limits (STELs) are regulatory standards for the permissible exposure levels to harmful substances over a short period, typically 15 minutes. They are designed to protect against acute health effects and are informed by scientific standards like those from the EMA and EPA.
Step-by-step explanation:
Short Term Exposure Limits (STELs) are guidelines for setting permissible exposure levels to contaminants or potentially hazardous substances over a short period of time. The Environmental Protection Agency (EPA) and other regulatory agencies define STELs to protect human health and the environment from the acute effects of chemical exposure. These limits are informed by toxicological data, such as those provided in the European Medicines Agency's (EMA) guidance on toxicokinetics.
STELs typically represent the maximum concentration to which workers can be exposed for a short period of time, usually 15 minutes, without suffering from irritation, chronic or irreversible tissue damage, or narcosis of sufficient degree to increase the likelihood of accidental injury, impair self-rescue, or materially reduce work efficiency. The reference periods for STELs are crucial for ensuring workplace safety, especially in industries dealing with radiation, as indicated by the Ministry of the Environment of Japan and the International Commission on Radiological Protection (ICRP). Ensuing radiation safety measures involve using personal dosimeters and maintaining records of individual radiation doses to comply with exposure limits.
STELs also relate to the 'National Ambient Air Quality Standards' for criteria air pollutants set by the EPA, such as for sulfur dioxide (SO2) and nitrogen dioxide (NO2), where standards are based on averaging times that may affect these short-term limits.