This depends on whether it is high altitude or low altitude. High altitude can purify some oil fume pollution, and low altitude can completely purify oil fume. The purification rate of low-altitude aircraft is above 98%, and black smoke and thick smoke enter and exit in the form of steam, achieving a visual smoke-free effect of 2-3 meters. The oil fume concentration measured by environmental protection instruments can also reach the national standard 1.0, which actually purifies the oil fume products.