According to a report from the University of California Davis, Wildfires have contributed to long outbreaks of smoke in Australia, Brazil and the United States over the last 3 years. In 2020 air quality hit and remained at highly dangerous levels in all the west of the United States only settling to "unsafe" levels for weeks from August to November.
Following the fires, scientists observed that microbial cells had a favorable relationship with the particulate matter rich in the smoke. The findings suggest less that the smoke helps microbes but that it hinders what would otherwise keep them at safe levels. Smoke particulate matter provides 80 percent attenuation of UV-B and UV-A up to 74 percent radiation which would otherwise reduce biological aerosol viability. The energy use during a wildland fire varies by severity in time and space.
"The health impact of inhaling wildfire smoke increases dramatically during high-emissions wildfires and with long exposure," said Leda Kobziar, associate professor of Wildland Fire Science at the University of Idaho. "Yet, the risk of infection to the respiratory tract after this exposure is frequently overlooked."
Skies brimming with wildfire smoke are becoming seasonal standards in the U.S. and Australia. By 2020, wild fires in the West have set new records. With or without harmful microbes, prolonged exposure to wildfire can negatively affect the heart and lungs. Exposure to wildfire exacerbates respiratory allergic and inflammatory conditions, including asthma and bronchitis. The possibility of upper and lower respiratory tract infection is often underestimated following exposure to smoke from wildfires.
"We don't know how far and which microbes are carried in smoke," said Thompson, associate professor of Clinical Medicine at UC Davis. "Some microbes in the soil appear to be tolerant of, and even thrive under, high temperatures following wildfires."
Wildland fire's microbial content affecting the humans who breathe in smoke is appreciable. How far and which microbes are transported in smoke under various conditions are critical unknowns. Researchers say exploration of infections and indicators such as antibiotic use in populations subjected to wildfire smoke is a promising first direction. Climate change impacts on wildfire are predicted to lead to total emissions of 19 to 100% in California alone through 2100. It is important that atmospheric and public health sciences expand their perspectives to include the potential impact of smoke's microbial cargo on human populations.