Which of the following does not occur as the blood passes through systemic capillaries?

In systemic cappillaaries pH of blood falls as its CO2 content increases, so that when the PCO2 rises, the curve shifts to the right and the P50 rises. Most of the unsaturation of hemoglobin that occurs in the tissues is secondary to the decline in the PO2, but an extra 1-2% unsaturation is due to the rise in PCO2 and consequent shift of the dissociation curve to the right. Ref: Ganong's Review of Medical Physiology Twenty-Third Edition Page No: 611