The partial pressures of oxygen and carbon dioxide in alveoli are what compared to their partial pressures in air?

O2 lower, CO2 higher: Simple question, complex & variable answer, including at sea level. Ventilation to different alveoli is continuously being adjusted, under CNS control, so as to approximate blood perfusion. This matching, referred to as vq, is critical to efficient/optimizing lung function & changes with activity, body position, etc. Rbcs capturing o2 & blood plasma for co2 separated by 2 cells from alveolar air.