The protection principles of dust hazards include the following points: 1. Identify and evaluate hazards: Understand the source, particle type and concentration of dust in the working environment, and evaluate potential health risks. 2. Engineering control: reduce dust generation by changing working environment or process, such as closed equipment and exhaust system. 3. Management control: Take management control measures, such as formulating operating procedures, training employees, and maintaining equipment regularly, so as to reduce dust contact. 4. Personal protection: provide appropriate personal protective equipment, such as breathing apparatus, protective glasses and protective clothing. To protect employees from dust contact. 5. Monitoring and evaluation: regularly monitor the dust exposure level, evaluate the effectiveness of protective measures, and make necessary adjustments to control measures. 6. Training and education: Provide relevant training and education to employees to make them understand the hazards of dust and the correct protection methods.