The 2020 wildfires are affecting many communities both indirectly and directly in Washington, Oregon, and California. Researchers in San Diego have analysed and reported the spatial-temporal variability of daily Santa Ana Winds and fine particulate matter (PM2.5) in Southern California in recent years.
The work is published in the January 2020 peer-reviewed publication in the journal Geohealth. The link to the full article is available here.
Case study highlighting significant correlation between PM2.5 and wildfires. Daily gridded SAW vectors shown were obtained from Guzman‐Morales et al., 2016. (a) The Moderate Resolution Imaging Spectroradiometer Rapid Response System (https://lance.modaps.eosdis.nasa.gov/cgi-bin/imagery/gallery.cgi) satellite image shows the smoke plumes for fires burning on 22 October, and wind vectors represent wind velocity for that same day. High positive correlations are found in coastal zip codes, which remained with poor air quality conditions after (b) 2 weeks from the onset of the first wildfire. Fire perimeters display the total area burned and the date reflects the start of the fire.
AUTHORS:
Rosana Aguilera, 1 Alexander Gershunov, 1 Sindana D. Ilango, 2 , 3 Janin Guzman‐Morales, 1 and Tarik Benmarhnia 1 , 2
1 Scripps Institution of Oceanography, University of California San Diego, La Jolla CA, USA,
2 Department of Family Medicine and Public Health, University of California San Diego, La Jolla CA, USA,
3 School of Public Health, San Diego State University, San Diego CA, USA,
Corresponding author: Rosana Aguilera, Email: ude.dscu@rekcebareliuga1r.
ABSTRACT:
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.