The major purpose of the ozone layer is to protect the Earth and its creatures from the Sun’s ultraviolet (UV) radiation.
University of Saskatchewan (USask) physics professors Dr. Adam Bourassa (PhD) and Dr. Doug Degenstein (PhD), research associate Dr. Daniel Zawada (PhD) and PhD student Kimberlee Dube, along with researchers from major institutions such as the Massachusetts Institute of Technology and the NASA Goddard Space Flight Center, have collaborated on a project that assessed the chemical changes that occurred in the ozone layer as a result of wildfire smoke.
A range of satellites were used to analyze the upper atmosphere following the Australian wildfires that occurred in 2019 and into 2020. Three separate satellites took measurements of the amount of nitrogen dioxide in the air from the smoke region. The measurements were combined with model calculations to determine if components of the stratosphere were affected by the smoke emitted from the fires.
Study findings determined that if wildfire smoke reaches the stratosphere, chemical reactions take place on the smoke particles that decrease the amount of nitrogen dioxide in the stratosphere, leading to an increase in ozone destroying molecules, and thus a depletion of the ozone layer in areas affected by wildfires.
“We have developed algorithms to use measurements from the Canadian satellite instrument OSIRIS to produce concentration profiles of nitrogen dioxide and aerosol extinction,” said Bourassa.
Overall, loss of the ozone layer occurred at a rate of one per cent in March 2020 in locations affected by the Australian wildfires. With the ozone layer expected to recover at one per cent per decade under the Montreal Protocol environmental protection plan, the local rate of ozone depletion will impact the recovery rate if wildfire rates continue to increase due to climate change.
The effects of wildfire smoke on the ozone layer are similar to the effects of volcanic eruptions, according to the research team.
“We now expect that increasing wildfire activity in a warming world would slow the recovery of the ozone layer,” said Bourassa. “New satellite measurements that carefully track the magnitude and impact of wildfire aerosols are needed in order to untangle the effects of chemistry and climate change on the ozone layer.”
Although the study did not measure every likely factor playing into how smoke affects the ozone layer, it offers a glimpse into what the future could hold if climate change is uncontrolled.
The study was made possible with support from the Canadian Space Agency.
Link to the paper: https://www.pnas.org/doi/abs/10.1073/pnas.2117325119?af=R