China Occupational exposure limits for hazardous agents in the workplace-chemical hazardous agents in Air

Chemical hazardous agents（GBZ 2.1‑2019）-chemical hazardous agents in Air is a mandatory standard issued by the National Health Commission of the People's Republic of China. This standard specifies the permissible concentration-time weighted average (PC-TWA), permissible concentration-short term exposure limit (PC-STEL), and maximum allowable concentration (MAC) for chemical hazardous factors in workplace air. Covering various categories including inorganic compounds, organic solvents, and high molecular polymers, the standard includes hundreds of chemical substances and defines sampling protocols and testing methods for each category, serving as the statutory basis for employers to conduct detection and assessment of occupational disease hazards.