Air Bronchogram Lobar Pneumonia

A 34-year-old man presents with 3 days of sudden-onset high-grade fever (39.4°C), teeth-chattering rigor, right-sided pleuritic chest pain, productive cough with rusty-coloured sputum, and dyspnoea. Examination reveals reduced expansion on the right, dull percussion, bronchial breath sounds, and increased vocal resonance over the right lower zone. His CURB-65 score is 3 (confusion, urea >7, RR ≥30). Chest radiograph shows homogeneous consolidation of the right lower lobe with obliteration of the right hemidiaphragm. The structure marked **B** (air bronchogram—branching lucencies within the consolidation) is visible on the radiograph. What is the pathophysiological significance of this finding?