Thank you for your post, but please note:
Windy does not create any forecast data but instead only visualises forecast and actual data received from various third party providers.
Please see the following thread regarding PM2.5 data,especially in relation to the current situation in Australia:https://community.windy.com/topic/10900/air-quality-pm2-5-data-and-forecasts
The forecast visualisations are based on the forecast data received. So Windy has no part in the reliability of this.
If the actual conditions have changed relative to the previous forecast then the visualisation of this data will of course not reflect this.
PM2.5 is forecast data from https://www.copernicus.eu/en ( https://community.windy.com/topic/7924/cams-signs-partnership-with-weather-application-windy ) and it is updated every 24 hours., It is not actual data and with rapidly changing conditions such as the fires in Australia this may result in some differences..
For all layers you can check the source of the data by clicking the clock/time/info icon in the bottom right hand corner.
Please see the following screenshot: