The American Association of Governmental Industrial Hygienists (ACGIH) has published a new document revising its UV hazard function and dose limits. Among them, the dose limit in the far ULTRAVIOLET band was greatly increased, and the daily irradiation limit at 222nm was increased from 22mJ/cm² to 160 mJ/cm²(corneal irradiation) and 478mJ/cm²(skin irradiation),which was effectively extended Exhibition of far ultraviolet products in air purification, surface and water purification and other fields of promotion and application, and make ultraviolet purification application more safe. Compared to traditional 254nm uv solutions,222 nm uv does not penetrate deep enough to harm skin or eyes.