It would just be a matter of how much would come in if the windows were closed.
Air purifier while windows open.
However the only limitation here is that the performance of the purifier in a room with open windows is less than one with closed windows.
However how effective the air purifier is depends on both the purifier itself and the pollution level of the air.
Is going to be subjective.
The bottom line to the question.
Regardless most companies will use the terms air cleaner and air purifier interchangeably.
The air purifier is going to clean the area it is immediately contained to regardless.
Air purifier windows open or closed.
New particulates swirl around in the air all the time.
If you have used chemicals or have a source of bad quality of air like burning.
Obviously closing the windows is the most effective but if you have to balance outdoor pollution against vocs or co2 indoors it is possible to get some ventilation and significantly reduce pollution.
Fresh air has pollen smoke and other potential irritants.
I have allergies so i use an air purifier.
Even with a window open air purifiers can still meaningfully reduce particulate air pollution in the home by 60 in 20 minutes in our tests.
While air cleaners often include filters they are overall more robust in cleaning the air than air filters.
With 2 or more windows open often the air purifier will have almost no effect.
Humans pets air conditioning and heating systems and open windows are all responsible for introducing contaminants into a room.
Airflow with 1 vs 2 or more windows open can be dramatically different.
Keep your windows open to prevent locking irritants into rooms when air purifiers aren t running.
It is a common misconception that operating an air purifier for an hour or two in a room will sufficiently clean the air.
Create a stronger cross draft by opening windows on opposite sides of the room if possible.
If you can open a window in a room while the air purifier is working it is not a bad idea to mix in a little fresh air as well.
Most air purifiers can remove at least 99 97 of particles as small as 0 3.
My partner likes to open windows to get fresh air.
With only 1 window open there is some external air entering the room but the purifier can at least work with marginal efficiency.
Doors opened or closed it does not really matter.