Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal radiograph of the chest demonstrates low lung volumes , accentuating the cardiac contour and pulmonary vasculature . There is bibasilar atelectasis but increased airspace opacity at the left base concerning for pneumonia . No pleural effusion or pneumothorax is seen . Large hiatal hernia is noted .
    OUTPUT:
    
Asymmetric airspace opacity at the left lower lobe concerning for pneumonia .