Volatile Organic Compounds (VOC) Testing

1. Volatile Organic Compounds

Volatile organic compounds, commonly referred to as VOCs, is an abbreviation formed from the first letters of the three words: Volatile Organic Compounds. Total volatile organic compounds are sometimes also denoted as TVOC.

According to the definition by the World Health Organization (WHO), VOCs (volatile organic compounds) are various organic compounds with boiling points ranging from 50°C to 260°C at room temperature. In China, VOCs refer to organic compounds that have a saturated vapor pressure greater than 70 Pa at room temperature, a boiling point below 260°C under normal pressure, or all organic compounds that have a vapor pressure greater than or equal to 10 Pa at 20°C and are volatile.

They are typically categorized into non-methane hydrocarbons (abbreviated as NMHCs), oxygenated organic compounds, halogenated hydrocarbons, nitrogen-containing organic compounds, sulfur-containing organic compounds, and several other major classes.

Based on their chemical structures, they can be further divided into eight categories: alkanes, aromatic hydrocarbons, alkenes, halogenated hydrocarbons, esters, aldehydes, ketones, and others. The main components of VOCs include hydrocarbons, halogenated hydrocarbons, oxygenated hydrocarbons, and nitrogenated hydrocarbons, encompassing substances such as benzene series, organic chlorides, freons, organic ketones, amines, alcohols, ethers, esters, acids, and petroleum hydrocarbon compounds.

2. Types of Volatile Organic Compound Pollution

There are many types of volatile organic compound pollution, and there is currently no unified classification method. A common classification is based on the nature of the pollution sources, mainly including the following:

(1) Organic solvents. Organic solvents are solvents composed of organic substances as the medium. Common organic solvents include household cosmetics, hair care products, and detergents, as well as everyday utilitarian items such as adhesives, paints, and water-based coatings.

(2) Building materials. Building materials refer to some materials used in construction projects that are prone to emitting volatile odors, including coatings used indoors and outdoors, plastic panels, foam insulation materials, artificial boards, and other similar materials.

(3) Indoor decorative materials. Indoor decorative materials refer to coatings used inside buildings or other materials for interior decoration that are prone to emitting volatile odors, including wall coatings, wallpapers, and murals that easily produce volatile odors.

(4) Fiber materials. Fiber materials are made from natural or synthetic fibers and are commonly used for items such as carpets, tapestries, and chemical fiber curtains.

(5) Office supplies. Some office supplies are inherently volatile, such as printing ink. Others are not volatile themselves, but during operation, they emit a significant amount of heat, and some consumables are released along with the heat. For example, photocopiers and printers fall into this category, as they emit large amounts of harmful gases into the air during operation.

(6) Outdoor industrial gases. Outdoor industrial gases refer to gases emitted from industrial production or various machinery, covering a wide range, including gases volatilized during industrial processes, vehicle exhaust, photochemical smog, and so on.

3. Hazards

Most VOCs are toxic, and some are carcinogenic. For instance, certain harmful substances in the atmosphere, such as benzene, polycyclic aromatic hydrocarbons, aromatic amines, resin compounds, aldehydes, and nitrosamines, have carcinogenic effects or produce true tumor effects on organisms. Some aromatic amines, aldehydes, halogenated alkanes and their derivatives, and vinyl chloride have mutagenic effects. Many volatile organic compounds are flammable and explosive, posing safety risks. Under sunlight, VOCs undergo photochemical reactions with nitrogen oxides, hydrocarbons, and oxidants in the atmosphere, forming photochemical smog, which harms human health and crop growth. The main components of photochemical smog are ozone, peroxyacetyl nitrate (PAN), aldehydes, and ketones. These substances irritate people's eyes and respiratory systems, endangering human health and damaging crop growth.