We have had several positive reports about the Wein Personal Air Supply helping with bushfire smoke, which is currently very bad where we live on the mid-north coast.
If you are wheezing or affected, take a look at the science behind it at https://store16061019.ecwid.com/Wein-Personal-Air-Supply-p128364942
Basically the unit emits a cloud of positive ions that attach to the smoke particles that then all rush away from each other and from you.
lasts 30hrs per charge and costs $187.73
lasts about 60hrs per battery and costs $134.09