TORONTO - A new study says visits to emergency departments for asthma spiked during a first wave of unprecedented wildfire smoke in 2023, but patient numbers returned to normal during a second wave weeks later.

New research in CMAJ (Canadian Medical Association Journal) https://www.cmaj.ca/lookup/doi/10.1503/cmaj.241506 found an increase in asthma-related emergency department (ED) visits across Ontario following heavy smoke in early June 2023.