I want to trigger the foobot or air purifier fine dust sensor on the Rule Machine. Is there any way?
It appears that Foobot has an IFTTT integration (as does Hubitat.) Thus, I would think you could simply link both your Foobot and Hubitat to IFTTT. Then create a Hubitat Virtual Switch device, which would indicate whether or not there is an air quality concern (i.e. 'on' = bad air quality, 'off' = good air quality.) Once you expose this new Hubitat Virtual Switch to IFTTT, you should be able to incorporate it into one or two IFTTT automations based on your Foobot's air quality sensor value.
Once you have the Hubitat Virtual "Air Quality Switch" working, you can then use Rule Machine to perform whatever actions you'd like based on the status of the 'switch'.
I didn't think of that.