I have an air purifier in my bedroom. It measures PM1, PM2.5 and PM10 as well as TVOC (Total volatile organic components) and adjusts it's air intake according

I have an air purifier in my bedroom. It measures PM1, PM2.5 and PM10 as well as TVOC (Total volatile organic components) and adjusts it's air intake according to the air quality. Usually it runs at very low speed and is inaudible, even at night. When I start cooking downstairs, within a minute or so I hear the purifier upstairs ramp up to full speed.