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Wildfires and COVID: Is climate change making the pandemic worse?

Devastation caused by wildfire in California, USA
Devastation caused by wildfire in California, USA   -   Copyright  Noah Berger/AP
By Tim Gallagher

With wildfires increasing in frequency and intensity due to climate change, a new study shows this may make us more vulnerable to respiratory diseases - including COVID-19.

Research by Harvard TH Chan School of Public Health has found a direct link between wildfires in three US states and a surging rates of COVID cases and COVID related deaths.

Washington, Oregon and California were at their worst for 18 years in 2020, burning so intensely that smoke reached Northern Europe. Ever since, we’ve seen blazes rage in Turkey, Greece, Spain, Italy and Malta with the Greek president calling the wildfires the “worst ecological disaster” in decades.

By examining the amount of fine-particulate matter (PM2.5) emitted by the US fires, researchers were able to see a link between exposure to the pollution and COVID-19.

PM2.5 are particles in the air which are smaller than 2.5 micrometers in width.

Illnesses such as asthma and chronic obstructive pulmonary diseases (COPD) are already linked to exposure to PM2.5 but this study is the first to focus on COVID-19.

"The year 2020 brought unimaginable challenges in public health, with the convergence of the COVID-19 pandemic and wildfires across the western United States,” says lead author of the study, Francesca Dominici.

“We are providing evidence that climate change...and the pandemic are a disastrous combination," she continues.

Why do wildfires increase COVID-19 cases?

PM2.5 increases the likelihood of respiratory illnesses by penetrating deeply into the lungs and damaging the alveolar wall.

Across 92 counties in the three states the researchers looked at the connection between county and daily data on PM2.5 air concentrations, wildfire days, and the number of COVID-19 cases and deaths.

This revealed that between August and October 2020 PM2.5 concentration in the air rose on wildfire days and the effects on lasting COVID cases and deaths could last up to four weeks after the fire.

Looking at individual wildfire days it was found that Butte, California, and Whitman, Washington, had the highest number of COVID-19 cases connected to high levels of PM2.5.

In Butte 17.3 per cent of cases were attributable to the wildfire particulates and in Whitman it was 18.2 per cent.

Butte also had one of the highest percentages of COVID deaths linked to wildfires with 41 per cent of fatalities linked to high levels of PM2.5.

Across Washington, Oregon and California the total number of COVID-19 cases and deaths attributable to increases in PM2.5 from wildfires was 19,700 and 750 respectively.

Is climate change going to cause more illness?

Wildfires have increased around the world in 2021 causing devastating effects to land, homes and livelihoods.

"Climate change will likely bring warmer and drier conditions to the West (of the United States), providing more fuel for fires to consume and further enhancing fire activity,” says Dr Domici.

“This study provides policymakers with key information regarding how the effects of one global crisis -climate change - can have cascading effects on concurrent global crises - in this case, the COVID-19 pandemic," she continues.

Concerns over public health and climate change are high with extreme weather events like heatwaves, air pollution and flooding all causing disruption to daily life.