Scented products cause indoor air pollution on par with car exhaust

My air purifier was instantly showing red and running at max fan speed, it took me a while to realize that the incense i ignited is causing it to detect the extra particles in the air and spin up. Now the question is whether this is a limitation in air purifiers, their inability to distinguish inert and harmless particles from harmless ones, because all they do currently is just detect particles, not their nature.

What makes you think soot from incense is “harmless”?

How sure are you that it's harmless? Campfire smoke is pretty bad for your lungs.