Heat/mortality sensitivities in Los Angeles during winter: a unique phenomenon in the United States

TitleHeat/mortality sensitivities in Los Angeles during winter: a unique phenomenon in the United States
Publication TypeJournal Article
Year of Publication2018
AuthorsKalkstein A.J, Kalkstein L.S, Vanos J.K, Eisenman D.P, Dixon P.G
JournalEnvironmental Health
Volume17
Date Published2018/05
Type of ArticleArticle
ISBN Number1476-069X
Accession NumberWOS:000431521500001
Keywords10 canadian cities; Air masses; air-pollution; climate-change; DLNM; Environmental Sciences & Ecology; events; health; heat; Heat-related mortality; Human mortality; impacts; Los Angeles; Public, Environmental & Occupational; Synoptic weather; temperature; us cities; wave; Winter heat waves
Abstract

Background: Extreme heat is often associated with elevated levels of human mortality, particularly across the mid-latitudes. Los Angeles, CA exhibits a unique, highly variable winter climate, with brief periods of intense heat caused by downsloping winds commonly known as Santa Ana winds. The goal is to determine if Los Angeles County is susceptible to heat-related mortality during the winter season. This is the first study to specifically evaluate heatrelated mortality during the winter for a U.S. city. Methods: Utilizing the Spatial Synoptic Classification system in Los Angeles County from 1979 through 2010, we first relate daily human mortality to synoptic air mass type during the winter season (December, January, February) using Welch's t-tests. However, this methodology is only somewhat effective at controlling for important inter-and intra-annual trends in human mortality unrelated to heat such as influenza outbreaks. As a result, we use distributed lag nonlinear modeling (DLNM) to evaluate if the relative risk of human mortality increases during higher temperatures in Los Angeles, as the DLNM is more effective at controlling for variability at multiple temporal scales within the human mortality dataset. Results: Significantly higher human mortality is uncovered in winter when dry tropical air is present in Los Angeles, particularly among those 65 years and older (p < 0.001). The DLNM reveals the relative risk of human mortality increases when above average temperatures are present. Results are especially pronounced for maximum and mean temperatures, along with total mortality and those 65 +. Conclusions: The discovery of heat-related mortality in winter is a unique finding in the United States, and we recommend stakeholders consider warning and intervention techniques to mitigate the role of winter heat on human health in the County.

DOI10.1186/s12940-018-0389-7
Short TitleEnviron Health-Glob
Student Publication: 
No