A variety of occupational activities are exposed to nitrogen oxides, such as the manufacture of nitric acid or the use of nitric acid to dip and wash metals; the manufacture of nitro explosives, nitrocellulose, nitro compounds such as picric acid, the diazotization process of aniline dyes, and the exposure of organic materials (e.g., wood shavings, paper shavings) to concentrated nitric acid; explosions of nitro explosives, nitrogen-containing substances, and the combustion of nitric acid; and gases produced by satellite launches and rocket propulsion also contain a large amount of nitrogen oxide gases. Welding, arc welding, gas cutting and arc light, the resulting high temperature can make the air oxygen and nitrogen combined into nitrogen oxides; automobile combustion engine exhaust also contains nitrogen oxides. In addition, some green fodder and grains contain potassium nitrate, in poor ventilation, lack of oxygen under the conditions of fermentation, potassium nitrite and oxygen can be generated, further potassium nitrite into nitrite, when the barn fermentation temperature increases, nitrite decomposition into nitrogen oxides and water, resulting in a “barn gas poisoning” (silogaspoisoning) a variety of different production processes formed in the nitrous oxide, its composition is different. So, how to prevent two lungs full of corn grain shadow? Here are the preventive measures of two lungs full of corn grain shadow: 1, suffering from obvious respiratory diseases such as chronic bronchitis, emphysema, bronchitis, asthma, bronchial dilatation, pulmonary heart disease and obvious cardiovascular system diseases, should not be engaged in this operation. 2.Reform the process of technology, try to close the production, strengthen the ventilation and detoxification equipment, so that the concentration of nitrogen oxides in the air in the workshop is below the maximum permissible concentration stipulated by the state. 3.Regularly overhaul the equipment, reduce the phenomenon of running, risking, dripping and leaking, and strictly abide by the safety operation regulations. 4.Strengthen the awareness of personal protection, such as wearing air-supplied gas masks as needed.