What are volatile organic compounds?
In our daily lives, we encounter numerous substances that affect the air quality; volatile organic compounds make up the bulk of urban and indoor pollution.
They are organic compounds, which means they contain carbon atoms (often bonded to hydrogen, oxygen, fluorine, or chlorine). This structure makes them particularly reactive in the atmosphere.
In simple terms, a VOC (Volatile Organic Compound) is a chemical substance primarily composed of carbon that 'flies' away easily, turning into gas or vapor at room temperature.
Sources of VOCs in indoor air are diverse and affect all household objects and activities: mainly building and furnishing materials (whose emissions persist for years), cosmetic or deodorizing products, cigarette smoke, cleaning agents, and various products (e.g. glues, adhesives, solvents, paints), recently washed clothes in the laundry, heating devices, printers, and copiers.
VOCs are also present in outdoor environments from vehicle exhausts, industrial emissions, and natural sources such as vegetation. Among the most dangerous, from a toxicological and mutagenic point of view, is formaldehyde.
Due to their widespread use and volatility, VOCs account for the vast majority of both urban and indoor air pollution.
Effects of VOCs on health
Exposure to high concentrations of VOCs can have harmful effects on human health. Certain groups, such as children, the elderly, and people with pre-existing health conditions, may be particularly sensitive to these effects.
The health impact of VOCs is extremely variable and depends on the specific substance, its concentration in the air, and the duration of exposure.
Some have a pungent odor that acts as a 'warning signal,' while others are odorless and insidious.
Short-term exposure can cause irritation of the eyes, nose, and throat, as well as headaches, dizziness, and nausea.
Long-term exposure over many years, even at low doses, can lead to much more severe pathologies. VOCs have been linked to respiratory problems, allergies, neurological disorders, and even certain types of cancer.
Photocatalytic filtration for VOCs abatement.
Photocatalytic filtration is a photochemical reaction in which a catalyst (titanium dioxide) irradiated by light, decomposes pollutants in whose composition carbon is present.
It is one of the best air purification methods, as it does not simply filter pollutants (in the traditional sense of "retaining"), but destroys them and, therefore, manages to be effective even against substances too small to be physically blocked by a filter, such as, for example, bad smells.
In addition, titanium dioxide is known for its bactericidal properties, making TiO2 photocatalytic filters highly effective at removing viruses and bacteria from the air (for more details, see the article on the bactericidal power of titanium dioxide).
To determine whether photocatalytic filtration is the right solution for your specific issue, you must first establish if the problem is caused by a substance classified as a VOC. You can do this by downloading the full list of volatile organic compounds available at the bottom of this article or by visiting the US Environmental Protection Agency (EPA) website.
Moving beyond traditional filters
COV's List
Since the definition is very broad, this category encompasses a wide variety of molecules: not only saturated, unsaturated, cyclic, and aromatic hydrocarbons, but also compounds that include heteroatoms (meaning elements other than carbon and hydrogen) such as oxygen, nitrogen, sulfur, and halogens.
In everyday life, these substances are found in many common products:
- Aliphatic hydrocarbons (e.g., propane, butane, hexane): used primarily as fuels, in refrigerant gases, and within detergents.
- Halogenated hydrocarbons (e.g., chloroform, methylene chloride, pentachlorophenol): used for the production of pesticides, industrial degreasers, and refrigeration systems.
- Aromatic hydrocarbons (e.g., benzene, toluene, xylenes): essential components of paints, coatings, adhesives, and detergents.
- Alcohols: substances found in a wide range of products, from adhesives and thinners to cosmetics and detergents.
- Aldehydes (e.g., formaldehyde, acetaldehyde): utilized for their preservative and disinfectant properties, they are found in fungicides, germicides, and even in furniture materials.
According to the criteria established by the European Union, a compound is classified as a VOC if it exhibits a specific volatility, namely a vapor pressure of 0.01 kPa or greater at a temperature of 20°C.
Therefore, there is no all-encompassing list for volatile organic compounds (VOCs), as this category includes thousands of different molecules linked by their ability to evaporate rapidly at ordinary temperatures.
The list available for download by clicking the button is, nonetheless, a comprehensive and nearly exhaustive summary.
For a double-check, you can also visit the United States Environmental Protection Agency (EPA) website.
