Yes, you can get outside air from a window air conditioner by running just the fan mode without activating the cooling function. Most window air conditioners have a fan-only mode that circulates the air without cooling it. By selecting this mode, you can bring in fresh air from outside into your space.
It's important to note that the fan mode of a window air conditioner does not filter or condition the incoming air like a dedicated ventilation system would. Therefore, the quality of the air entering your space will depend on the outdoor air conditions and any pollutants present. Additionally, running the fan without the cooling function will not dehumidify the air.
If you're specifically interested in bringing fresh outdoor air into your space, you may want to consider alternative ventilation options like opening windows, using exhaust fans, or installing a dedicated ventilation system designed for this purpose. These methods can provide better control over the airflow and allow for proper filtration and conditioning of the incoming air.