The closed gas hood is a device used to collect harmful gases and particles in analytical experiments. When using closed gas hood, it is often necessary to consider the efficiency of gas collection, that is, the efficiency of collecting harmful gases. Therefore, we need to discuss the gas collection efficiency of closed gas hood. First of all, the gas collection efficiency of closed gas hood is often affected by many factors. The main factors may include the following aspects:

The air flow performance of closed gas hood is one of the important factors affecting gas collection efficiency. If the air flow in the closed hood is unstable and uneven, some harmful gases and particles will not be fully collected, which will affect the gas collection efficiency.

The selection and installation position of sampling probe will also affect the gas collection efficiency of closed gas hood. If the sampling probe is not properly selected or installed in an unreasonable position, some harmful gases and particles will not be exposed, thus affecting the gas collection efficiency.

The design and material of closed gas hood is also one of the important factors affecting gas collection efficiency. If the design of the closed gas hood is unreasonable or the material used is not good enough, the durability and sealing of the closed gas hood will be reduced, which will further affect the gas collection efficiency. 

The influence of ambient temperature and humidity will also have a certain impact on the gas collection efficiency of closed gas hood. If the ambient temperature and humidity are high, it will lead to the volatilization and dispersion of harmful gases and particles, thus affecting the gas collection efficiency.

Considering the above factors, generally speaking, the gas collection efficiency of closed gas hood can reach above 90%. However, the specific gas collection efficiency needs to be evaluated according to the actual situation, and pay attention to the influence of the above factors. At the same time, it is necessary to choose different sampling probes and sampling methods for different harmful gases and particles to ensure the gas collection efficiency of the closed gas hood to be excellent. In a word, the gas collection efficiency of closed gas hood is one of the important factors affecting the correctness of experimental results such as analysis and test. When using closed gas hood, it is necessary to ensure its gas collection efficiency, so as to obtain accurate and reliable analysis results.