SACRAMENTO, Calif. — Cases of COVID-19 rose sharply last year in Reno, Nevada, when heavy layer of wildfire smoke settled over the city, according to scientists at the Desert Research Institute, and they and other scientists are postulating that there is a link between air pollution and increased susceptibility to the new coronavirus.
“Our results showed a substantial increase in the COVID-19 positivity rate in Reno during a time when we were affected by heavy wildfire smoke from California wildfires,” said Daniel Kiser, a co-lead author of the study published in the Journal of Exposure Science and Environmental Epidemiology. “This is important to be aware of as we are already confronting heavy wildfire smoke ... with COVID-19 cases again rising in Nevada and other parts of the western U.S.”
Kiser, an assistant research scientist of data science at the institute, said he became interested in studying the effect of the microscopic particulate matter from wildfires after reading a Canadian scientist’s article on the dual effect of confronting both issues at the same time.
In the preface to her work, senior scientist Sarah Henderson of the British Columbia Center for Disease Control, wrote: “As we enter the wildfire season in the northern hemisphere, the potential for a dangerous interaction between SARS-CoV-2 and smoke pollution should be recognized and acknowledged. This is challenging because the public health threat of COVID-19 is immediate and clear, whereas the public health threat of wildfire smoke seems distant and uncertain in comparison. However, we must start preparing now to effectively manage the combination of public health threats.”
Kiser is hoping that his research results will motivate people to get vaccinated and to wear masks to reduce their exposure to the virus and to tiny wildfire particulate matter that measures 2.5 micrometers or less.
That’s about 1/30th the size of a human hair at its largest. Scientists refer to it as PM 2.5 for short.
To analyze the relationship between this fine wildfire ash and COVID-19 positivity rates, Kiser and his team collected data from the Washoe County Health District and the region’s big hospital system, Renown Health.
He said they discovered that the PM 2.5 was responsible for a 17.7% increase in the number of COVID-19 cases that occurred during a period of prolonged smoke that took place between Aug. 16, 2020, and Oct. 10, 2020.
Washoe County’s 450,000 residents, many of whom live in Reno, experienced 43 days of elevated PM 2.5 during that period, researchers said, compared with 26 days for residents of the San Francisco Bay Area.
“We had a unique situation here in Reno last year where we were exposed to wildfire smoke more often than many other areas, including the Bay Area,” said Dr. Gai Elhanan, co-lead author of the study and an associate research scientist of computer science at the institute. “We are located in an intermountain valley that restricts the dispersion of pollutants and possibly increases the magnitude of exposure, which makes it even more important for us to understand smoke impacts on human health.”