近几十年来 ,世界各地的肿瘤发病率都在不断增加 ,尤其肺癌更加明显。肺癌发生率城市高于农村 ,工业区高于非工业区。在我国北京、上海、鞍山等城市 ,肺癌的发病率已上升至所有肿瘤的第一位。肺癌病因学研究指出 ,空气污染、吸烟、某些职业是该病的主要原因。空气污染在某些城? In recent decades, the incidence of tumors in various parts of the world has continued to increase, especially in lung cancer. The incidence of lung cancer is higher in cities than in rural areas, and industrial areas are higher than non-industrial areas. In cities such as Beijing, Shanghai and Anshan in China, the incidence of lung cancer has risen to the top of all tumors. Lung cancer etiology studies have pointed out that air pollution, smoking, and certain occupations are the main causes of the disease. Air pollution in some cities?