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What are VOCs?

Vulnerable, VOCs: Not to be underestimated: VOCs are complex in composition, and there are more than 300 VOCs that have been monitored, mainly from architectural decoration, organic chemicals, petroleum and petrochemical, packaging and printing, surface coating and other industries. One of the four major atmospheric pollutants of VOCs is an important factor in the formation of PM2.5 and photochemical smog. It can damage the human nervous system, blood components and cardiovascular system, and has a great impact on human health and social environment.

There are two main sources of VOCs in the air: natural sources and anthropogenic sources. Natural sources mainly come from vegetation discharge, forest fires, wildlife discharge and wetland anaerobic processes, and the impact on human health is generally within the controllable range.

Anthropogenic sources include mobile sources and fixed sources. Mobile sources include automobiles, ships, airplanes and other vehicles that consume fossil fuels; fixed sources are divided into sources of life and industrial sources, and sources of life mainly refer to building decoration, soot emissions, waste incineration, straw burning, garment dry cleaning, etc.; There are many source design industries, including organic chemicals, petroleum and petrochemicals, packaging and printing, and surface coating.

VOCs from industrial sources have large emission intensity, high concentration and many types of pollutants, which are the major polluters. Industrial sources of VOCs are mainly produced from the use of VOCs-containing products, processes using VOCs as raw materials, production of VOCs, storage and transportation of organic matter.

A, offline monitoring: gas chromatography-mass spectrometry (GC/MS) method is the mainstream

For off-line monitoring, the sampling methods of VOCs in the air can be divided into direct sampling, dynamic sampling and passive sampling. Sample pretreatment methods include solvent analysis, solid phase microextraction, low temperature preconcentration-thermal analysis, and the like. Methods for analyzing VOCs include gas chromatography, high performance liquid chromatography, gas chromatography-mass spectrometry, and the latest development of proton transfer reaction mass spectrometry.

B, online monitoring: gas chromatography - hydrogen flame ionization monitoring method (GC-FID)

Compared with the long analysis time and the lag of the analysis data, offline monitoring has the advantages of high efficiency, short preprocessing time and continuous data, which can effectively reduce the error caused by human error.

山东圣文环保科技有限公司

VOCs在线监测 VOCs online monitoring