Smoky skies can harm our lungs and the environment. But even when the sky seems to clear of smoke, authors of a new study say leftover smoke particulates can continue to impact the atmosphere for more than a week.
The study, published in the journal Environmental Science and Technology, looks at data from the Mount Bachelor Observatory in the summer of 2019. Though wildfire was calm that year, researchers found wildfire smoke particulates from Northern California and even some from as far away as Siberia. Those particulates were more than a week old and still contained climate-changing chemicals.
Qi Zhang — a professor with the University of California, Davis, who worked on the study — said the air at the observatory was, “kind of like a typical pristine, remote atmospheric condition.”
“However, if we look at the atmospheric chemistry measurements, we see clear signals for a wildfire emission,” Zhang said.
She said this information is crucial in knowing more about the impacts of wildfire smoke, even when there doesn’t appear to be any around.
The chemicals in old wildfire smoke can change the temperature by scattering or absorbing solar radiation. They can also seed clouds to produce rain or snow.
In the study, researchers found that particulate matter concentrations within old wildfire smoke were low, but oxidized aerosols from burning biomass — like trees and shrubs — were found throughout the samples. These aerosols were larger in old smoke samples compared to those found after a fire starts.