1. Traditional ducted fume hoods have insufficient coverage or poor effectiveness, resulting in a large amount of toxic, harmful, and corrosive gases and chemical reagent volatiles diffusing in the laboratory. The long-term inhalation of these "mixed gases" poses a serious threat to the respiratory health of experimental personnel.

2. Some laboratory ventilation systems are aging, and the wind speed and air exchange rate do not meet the standards; Chemical storage is arbitrary and not effectively isolated from the operating area; The lack of effective air purification equipment for operations such as weighing and configuration that are prone to generating dust and aerosols can result in cross contamination and health risks.

3. Unclear chemical ledger and non-standard usage records; The safety regulations remain on paper and have not been integrated into daily operational processes; Inadequate personnel training and insufficient awareness of potential risks have further amplified environmental hazards.

GBZ 2.1-2019 Occupational Exposure Limits for Hazardous Factors in the Workplace Part 1: Chemical Hazardous Factors It is a mandatory national occupational health standard in China. The core content is to establish three types of statutory occupational exposure limits for various harmful chemical factors in the workplace air, forming a complete protection system:

1. Time weighted average allowable concentration (PC-TWA): Refers to the average allowable exposure concentration for an 8-hour workday and a 40 hour workweek, weighted by time. Used to prevent chronic health damage caused by long-term repeated exposure.

2. Short term exposure permissible concentration (PC-STEL)Under the premise of complying with PC-TWA, the concentration allowed for short-term (15 minutes) exposure. Intended to prevent excessive short-term peak concentration from causing irritation, acute effects, or chronic health damage.

3. Maximum allowable concentration (MAC)The concentration of toxic chemicals at the workplace should not exceed at any time during a working day. Suitable for chemicals that may cause acute damage.

OELOccupational exposure limitIt is a general concept that refers to the concentration limits of harmful factors in the workplace air that should not exceed legal or recommended conditions in order to protect the health of workers. It is the core technical indicator for occupational health risk management in the workplace. As a conceptual category, OEL includes various specific types such as time weighted average concentration (TWA), short-term exposure limit (STEL), and maximum allowable concentration (MAC).

TWA (Time Weighted Average Concentration)It is the most important and commonly used specific type and expression of occupational exposure limits. It specifically refers to the average exposure concentration calculated by weighting time within a specified normal 8-hour workday or 40 hour workweek. Its core purpose is to control the chronic health risks of workers caused by long-term and repeated exposure to harmful substances.

GB/T 18883-2022 "Indoor Air Quality Standards"The limit requirements for indoor chemical pollutants have been significantly tightened, with the highly concerned formaldehyde standard being tightened from the original 0.1 mg/m ³ to 0.08 mg/m ³. In addition, nitrogen dioxide, trichloroethylene, andtetrachloroethyleneWe will continue to strictly control the concentrations of volatile organic compounds (VOCs) such as benzene, toluene, and xylene, as well as common pollutants such as ozone and carbon monoxide, in order to establish a more comprehensive and stringent indoor chemical pollution control system and better safeguard human health.