On this episode of Mythbusters, we find out if farting into an air purifier will cause it to register the air as foul.
This dude Anthony DeGol put the myth to the test with his Dyson Air Purifier. After a quick Google, it appears the model he is using in the experiment is the Dyson Pure Cool TP04 Purifying Fan which goes for a cool $569.99 and "senses pollutants in real time" and "automatically detects and reports air quality levels in real time on PM 2.5, PM 10, VOC and NO2" according to the product page on Dyson's website. I have no idea what that actually means but it seems pretty high tech since it has a little display that shows you the air quality levels in real-time.
Anyways dude puts out a banger on the side of the fan that draws air towards it and sure enough, the AQ level nosedives into the orange area meaning the air is polluted.