There are more than 180 million vehicles in our country; the automobile exhaust from these vehicles has become the top killer of fresh air.

        The main pollutants of vehicle exhaust contain carbon monoxide, hydrocarbons, nitrogen oxides and carbon particulates, which are in the zone of breathing. It causes great harm to atmospheric environment and the health of human. For example, hydrocarbons contain benzene, a highly carcinogenic polycyclic aromatic ingredients; nitrogen oxides has potential long-term damage to human body health, if serious it can cause ocular, nasal, lung diseases and even cancer; carbon particulates cause undesirable visual pollution, tiny particulates particles can enter respiratory tract and deposition in the lung cells which will cause respiratory system disease and even cause lung cancer.