Leo mentioned Australia fires during first call on Tech Guy show 1659. Here are some photos from our point of view.
Air quality has been over the top since just before Christmas, with 2 days of clarity (you can see one of them in photo of hill day after fire, 11 Jan).
Using Dyson Cool Tower air purifiers to make inside of house bearable. Great tech. Controlled and monitored from anywhere by phone. Provides closest AQI measurement outside our house, but I don’t know where they get the data. As example, Australian Environmental Protection Agency measurement for nearest town (5km) was 150. Dyson showed 750. Took the air purifier outside, and it showed 740. (photo with street sign taken at that time. There is a hill less than 1 km away in that photo).
Had some initial teething problems with units, and Dyson does not provide any technical support contact number, so got on Twitter (I only use Twitter for emergencies), and low and behold, they responded.