Wildfire smoke has caused rise in Covid infections and deaths, study finds

Researchers speculate that smoke helps spread the virus and weakens lungs, making symptoms more severe

Pollutants in smoke billowing from huge wildfires in the west of America have probably caused an increase in Covid-19 infections and deaths across several US states, new research has found.

Last year more than 10m acres of land were torched by wildfires, with five out of the six largest fires ever documented in California occurring within just a few months. The burning trees, shrubs and buildings gave off enormous plumes of smoke containing small particles of soot.