In normal air quality circumstances, outdoor air is generally less polluted than indoor air, unless you live next to an environmental pollutant source like a factory or freeway or if it is allergy season in your area. Having a window open while running your Molekule air purifier should not impact its effectiveness. We particularly recommend opening windows during and after cleaning a room, when using chemical detergents and running your Molekule air purifier on its highest fan setting.
Check out our blog to learn more about air quality.