The existing form and nature of respiratory hazard

Normal air consists of 78% nitrogen, 21% oxygen and a small amount of inert gas. When there are harmful substances in the air, that is, any gaseous or granular substances that do not exist in the normal air and whose concentration exceeds the individual concentration range specified in the national occupational health standards constitute respiratory hazards< There are five forms of harmful substances in the air, they are: 1. Dust: small solid particles suspended in the air, which are generally produced by the crushing of solid materials by mechanical force. For example, ore excavation, such as coal dust, silica dust, cement dust, etc; Asbestos dust is fibrous and belongs to dust. High temperature resistant gloves