Related and also useful US-based sites:

Fire incident map: https://inciweb.wildfire.gov/

Smoke and fire map: https://fire.airnow.gov/

Pretty cool. I think if I remember correctly you can get rid of the abrupt shudder when switching between leaflet rasters by first drawing the new raster with full transparency, and then make the new raster opaque and make the old raster transparent.

For the US (and parts of Canada!), NOAA provides the HRRR smoke model:

https://rapidrefresh.noaa.gov/hrrr/HRRRsmoke/

3D animated air pollution map of the earth:

https://www.iqair.com/earth