Canadian wildfires choke U.S. cities with the world's worst air quality
New York and nearby US cities are so badly affected by Canada’s fires, BBC reports.
But the smoke is also reaching Europe, says Albert Ansmann at the Leibniz Institute for Tropospheric Research.
He and his colleagues can detect the particles with laser instruments pointed upwards that measure smoke-reflected light. Hot air over a forest fire causes the smoke to rise by 2.7km, and when it absorbs sunlight, it can ascend to 10-12km height, Dr Ansmann explains.
Smoke from the North American fire season has travelled to Europe’s skies almost every summer for the past 10 years. It travels on winds from west to east for several weeks to months. The smoke particles stay in the air until they get washed out by rain or clouds.
It usually remains in the stratosphere for a few weeks but the concentration decreases over time as it spreads further out. After the large Canadian fires in 2017, smoke was detected in the stratosphere for more than half a year afterwards.
But the record-breaking size of the fires this year means there is much more smoke in the air, pushing more smoke around the globe, Dr Ansmann explains.
