According to the industry classification standards formulated by the Ministry of Environment, the pharmaceutical and chemical industry can be divided into traditional Chinese medicine pharmaceutical industry, fermentation pharmaceutical industry, mixed formulation pharmaceutical industry, chemical synthesis pharmaceutical industry, extraction pharmaceutical industry, and biotechnology pharmaceutical industry. Among them, the fermentation pharmaceutical industry and chemical synthesis pharmaceutical industry are major emitters of VOCs waste gas. China is a major producer of chemical raw materials, especially for fermented pharmaceutical products, with its production capacity and output ranking first.

1. Main sources

According to the production process, pollution generation and discharge nodes, and pollution characteristics of the pharmaceutical industry, the main sources of waste gas in the pharmaceutical industry are as follows:

① During the production process of raw materials, some organic solvents evaporate and emit gases with a foul odor;

② The drug dust particles generated in the crushing and screening section. The main pollutant is VOCs pollution caused by the volatilization of organic solvents in raw materials during the production process. For example, emissions from reaction vessels during the production process, including process exhaust from reaction vessels, exhaust from exhaust recovery devices, and exhaust from safety relief devices, as well as small amounts of emissions from distillation systems and tank area systems. In addition, production workshops and utilities also generate a portion of unorganized waste gas during the production process.

2. Emission characteristics

Due to the particularity of pharmaceutical and chemical production processes, their exhaust emissions also have significant characteristics, mainly manifested in the following aspects:

(1) There are usually many emission points for exhaust gas, covering almost every production equipment, and the emission volume is large. The phenomenon of unorganized emissions is serious, resulting in high concentration of exhaust gas at the factory boundary;

(2) Due to the intermittent nature of the reaction, the exhaust gas is emitted intermittently, resulting in unstable air flow;

(3) Due to the complexity of solvents, the concentration and types of pollutants in exhaust gas vary greatly. Even the same device may emit different types and properties of pollutants at different times, resulting in highly unstable emissions;

(4) Most of the exhaust gases are odorous VOCs with strong diffusivity, low odor threshold, and a wide range of impacts;

(5) Due to the special nature of production materials, the reaction process is generally more intense, and the risk of production accidents is greater. In addition, the level of production equipment and process technology has not yet reached a high level. If not managed properly, it can lead to more accidents such as "leakage" and emissions.

Volatile organic compounds contain various components, complex components, and are very harmful. They are air pollutants widely recognized by countries around the world after sulfur dioxide and nitrogen oxides. It is necessary to monitor and control VOCs pollution. Odor is a gaseous substance that can stimulate the sense of smell, cause unpleasant sensations, and damage the environment. Due to the influence of the olfactory system, odors can cause psychological discomfort and may lead to physical discomfort, and some odorous substances, such as organic sulfides, phenols, hydrogen sulfide, and benzene, are toxic to humans. As a typical environmental hazard, odor pollution is recognized by countries around the world. Studying the characteristics of VOCs emissions and harmful gases in the pharmaceutical industry is the foundation and key to preventing and controlling VOCs. Studying the unpleasant gas pollution characteristics of VOCs and the pharmaceutical industry is an urgent issue that needs to be addressed in environmental protection work.

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