They contain a feels good filter to make you think something is happening. But to actually filter the pollution you'd need a activated carbon filter for the n02 and a hepa filter for the smoke. Which none of them contain and would clog rapidly.

It's massively easier to just not create the no2 by replacing gas with induction, and to vent the smoke outside rather than trying to trap it in a filter. I think the introduction of cheap consumer air quality sensors like from IKEA will start to make this problem a lot more visible to people.