title: Development of acute inhalation reference exposure levels (RELs) to protect the public from predictable excursions of airborne toxicants.
abstract: Uniform guidelines have been developed for the derivation of 1-h acute inhalation reference exposure levels (RELs) applicable to the general public exposed routinely to hazardous substances released into the environment. Existing acute exposure guidance values developed by other organizations have been examined, and strengths and weaknesses in these existing guidelines have been identified. The results of that examination have led to the development of a reproducible and resource-intensive methodology to calculate acute inhalation RELs for 41 prioritized chemicals. Approaches to estimating levels protective against mild and severe acute effects are discussed in this report. The default methodology is the no-observed-adverse-effect level (NOAEL)/uncertainty factor (UF) approach using mainly reports in the peer-reviewed toxicological and medical literature. For two well-studied chemicals, ammonia and formaldehyde, the data allowed a benchmark dose (or concentration) methodology, as a departure from the default options, to be used. However, better human dose-response data from, for example, improved workplace monitoring correlated with symptoms, and more extensive epidemiological studies are needed before the departure from default approaches can be expanded to more substances.
authors.affiliation: Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, 1515 Clay Street, Oakland, CA 94612, USA. jcollins@oehha.ca.gov
authors.forename: James F
authors.initials: JF
authors.lastname: Collins
authors.forename: George V
authors.initials: GV
authors.lastname: Alexeeff
authors.forename: David C
authors.initials: DC
authors.lastname: Lewis
authors.forename: Daryn E
authors.initials: DE
authors.lastname: Dodge
authors.forename: Melanie A
authors.initials: MA
authors.lastname: Marty
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Parker
authors.forename: John D
authors.initials: JD
authors.lastname: Budroe
authors.forename: Richard H F
authors.initials: RH
authors.lastname: Lam
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Lipsett
authors.forename: Jefferson R
authors.initials: JR
authors.lastname: Fowles
authors.forename: Rupali
authors.initials: R
authors.lastname: Das
mesh_terms: D000393:Air Pollutants / Q000009:adverse effects* / Q000032:analysis; D000818:Animals; D019985:Benchmarking / Q000331:legislation & jurisprudence; D002140:California; D004305:Dose-Response Relationship, Drug; D017408:Guidelines as Topic / Q000592:standards; D006801:Humans; D019570:Inhalation Exposure / Q000331:legislation & jurisprudence; D019055:No-Observed-Adverse-Effect Level; D011634:Public Health; D012016:Reference Values; D018570:Risk Assessment / Q000331:legislation & jurisprudence; D013219:State Government; D015262:Xenobiotics / Q000009:adverse effects*
chemical_list: D000393:Air Pollutants; D015262:Xenobiotics