空气污染指数（Air Pollution Index, API）是反映空气污染物，如最常见的氮氧化物、悬浮粒子（来自汽车）和二氧化硫（来自工厂）水平的一个指数，一般是根据实际污染物观测值并用特定公式算出。指数常被用来对公众发布“空气质量日报”，让人们知道目前的 ...

During the Spring Festival holiday, the builders of the century project, the Pinglu Canal, remained at their posts, constantly updating the progress of the construction. On the 10th, reporters learned ...

A group of robot dogs wowed the crowd with their incredible performances during a Lantern Festival celebration on Wednesday. Robot dogs, with lion head-shaped decorations, perform dance alongside ...