Coronavirus Information for the UC San Diego Community

Our leaders are working closely with federal and state officials to ensure your ongoing safety at the university. Stay up to date with the latest developments. Learn more.

Santa Ana winds of Southern California impact PM2.5 with and without smoke from wildfires

TitleSanta Ana winds of Southern California impact PM2.5 with and without smoke from wildfires
Publication TypeJournal Article
Year of Publication2020
AuthorsAguilera R., Gershunov A, Ilango S.D, Guzman-Morales J., Benmarhnia T.
Date Published2020/01
Type of ArticleArticle
ISBN Number2471-1403
Accession NumberWOS:000509501000002
KeywordsAir quality; climate-change; coast air basin; Environmental Sciences & Ecology; exposure; health; particles; pm10; pm2.5; pollution; Public, Environmental & Occupational; quality; Santa Ana Winds; southern california; temperature; wildfire smoke

Fine particulate matter (PM2.5) raises human health concerns since it can deeply penetrate the respiratory system and enter the bloodstream, thus potentially impacting vital organs. Strong winds transport and disperse PM2.5, which can travel over long distances. Smoke from wildfires is a major episodic and seasonal hazard in Southern California (SoCal), where the onset of Santa Ana winds (SAWs) in early fall before the first rains of winter is associated with the region's most damaging wildfires. However, SAWs also tend to improve visibility as they sweep haze particles from highly polluted areas far out to sea. Previous studies characterizing PM2.5 in the region are limited in time span and spatial extent, and have either addressed only a single event in time or short time series at a limited set of sites. Here we study the space-time relationship between daily levels of PM2.5 in SoCal and SAWs spanning 1999-2012 and also further identify the impact of wildfire smoke on this relationship. We used a rolling correlation approach to characterize the spatial-temporal variability of daily SAW and PM2.5. SAWs tend to lower PM2.5 levels, particularly along the coast and in urban areas, in the absence of wildfires upwind. On the other hand, SAWs markedly increase PM2.5 in zip codes downwind of wildfires. These empirical relationships can be used to identify windows of vulnerability for public health and orient preventive measures.

Student Publication: