Wildfires and Covid-19
A look at Covid-19 death rates in LA County during California fire season
At the outbreak of Covid-19 in 2020, it seemed for the first few months that California was managing to control the virus at least better than expected. However, as spring turned to summer, many Californians began experiencing the effects of air pollution that worsen every year in the dry season along with a spike in Covid-19 cases that dwarfed that of March and April. A question that arose for me and other Californians was how these two issues could relate to each other.
September came, and cases in California began to flatten out again. While large wildfires that severely affect air quality are almost a norm now for Californians, September saw wildfires that seemed to put the fires we'd seen for the past decade to shame. Fires engulfed the West Coast from Oregon down to southern California, painting the skies red and yellow with smoke. In Los Angeles, residents were asked to stay inside not because of the virus, but because breathing in air so coated in ash posed a serious health risk.
Curious about whether especially poor air quality could worsen a respiratory illness like Covid-19, I decided to look at Covid death rates specifically through fire season (~June-September). I chose three time points: August 1st, September 1st, and October 1st. I wanted to see whether the time point during fire season had any correlation to rising Covid-19 death rates, and whether that correlation showed any valid information. I started off with October 1st as the peak of the fires across California and Oregon was around September 12th. While there's no exact date for the peak of the fires, I assumed that two weeks later was an appropriate estimate for when the county would possibly begin to see effects on death rate.
A size reference for particulate matter.
The Basics of Air Quality
The Air Quality Index (AQI) was developed by the EPA as a way of measuring a variety of factors contributing to poor air quality. The index runs from 0 to 500, good quality to poor quality. The index is divided into 6 categories from good to hazardous, each correlated to a different color. AQI takes into account ground-level ozone, particulate matter (PM2.5 and PM10), carbon monoxide, sulfur dioxide, and nitrogen dioxide.
Smoke/airborne ash falls into the category of particulate matter pollution.
While it's not clear from this data or from public LA county charts that these fires significantly affected the death rate in various parts of LA county, it seems important to take into account air quality specifically from wildfire smoke in such an at-risk area.
Current Data
The following map displays AQI reports from across the county (updated hourly) as well as currently burning fires and contained fire perimeters (updated daily). For those already at risk for Covid-19 due to respiratory vulnerability and illness, keeping AQI in mind would be helpful when deciding to spend time outside.
LA County Wildfires and Air Pollution Contrasted with Daily Covid Deaths per 100,000 Residents
Conclusion
While it's interesting to see changes in death rate over time, it's impossible to tell from this data whether air quality was a valid factor in the rising death rate over the months I've chosen. While that certainly may be a factor, the late summer and early spring of 2020 also saw more re-openings in LA county, which may have also contributed to rising death rates. However, the total case rate simultaneously went down from August to October. What then accounts for the small rise in death rate? According to researchers Xiao Wu et al., wildfires may have been to blame.
Nonetheless, staying updated on air quality data and current fires remains important, especially to those already struggling with respiratory illnesses. This map can help those individuals assess the risk of spending time outside in a time of increased threat of respiratory damage.
Works Cited:
“AQI Basics.” AQI Basics | AirNow.gov, AirNow.gov, U.S. EPA, www.airnow.gov/aqi/aqi-basics/.
“California Wildfires: Impact of Air Pollution during the Covid-19 Pandemic.” The BMJ, 29 Sept. 2020, blogs.bmj.com/bmj/2020/09/25/california-wildfires-impact-of-air-pollution-during-the-covid-19-pandemic/.
Wu, Xiao, et al. “Exposure to Air Pollution and COVID-19 Mortality in the United States: A Nationwide Cross-Sectional Study.” MedRxiv, Cold Spring Harbor Laboratory Press, 1 Jan. 2020, www.medrxiv.org/content/10.1101/2020.04.05.20054502v2.article-info.
