They are invisible and they are everywhere. In our daily lives, we are literally immersed in environments where volatile organic compounds (VOCs) circulate freely. These compounds represent a real risk to our health and the environment.
What are Volatile Organic Compounds VOCs?
Volatile organic compounds (VOCs) are carbon-containing chemical compounds whose main characteristic is that they evaporate easily at room temperature.
They are emitted from a variety of sources, including industrial chemicals, solvents, fuels, paints, cleaning products, personal care products and combustion processes.
VOCs can contribute to indoor and outdoor air pollution, and some of them are associated with negative effects on human health and the environment. Their health effects can vary widely, depending on the nature of the compound and the degree and period of exposure to it.
Volatile organic compounds VOCs: classification and examples
Volatile organic compounds (VOCs) can be classified into several categories according to their chemical structure. Some examples of each category are:
- Hydrocarbons: compounds consisting only of carbon and hydrogen atoms such as methane, ethane, propane, benzene, hexane.
- Alcohols, such as methanol, ethanol, isopropanol.
- Aldehydes, such as formaldehyde, acetaldehyde, benzaldehyde.
- Ketones, e.g. acetone, methyl ethyl ketone, cyclohexanone.
- Ethers, e.g. ethyl ether, methyl tert-butyl ether.
- Esters, e.g. ethyl acetate, methyl butyrate.
- Aromatic compounds containing aromatic rings. Examples: toluene, xylene, naphthalene.
In addition, VOCs can be classified according to their hazard:
- Compounds that are extremely hazardous to health, such as benzene, vinyl chloride and 1,2-dichloroethane.
- Class A compounds, which are those that can cause significant damage to the environment, e.g. acetaldehyde, aniline, trichloroethylene, etc.
- Class B compounds. These are those that have less impact on the environment, such as acetone and ethanol.
Harmful effects
As mentioned above, VOCs have negative effects on the environment and human health and it is therefore important to control their emissions.
Environmental impact
In combination with nitrogen oxides (NOx), which are mainly emitted by road traffic, VOCs can contribute to the formation of smog, a type of pollution that adversely affects air quality and can have harmful effects on human health and ecosystems.
In terms of water and soil pollution, VOCs can leach into groundwater and even contaminate drinking water.
In addition, when released into the soil, they can persist and affect soil quality and plant life.
Effects on human health
- Respiratory irritation: Many VOCs can cause irritation to the eyes, nose, throat and lungs, resulting in symptoms such as burning, itching, nasal congestion, coughing and shortness of breath.
- Respiratory problems: Exposure to VOCs can aggravate symptoms in people with pre-existing respiratory conditions such as asthma, trigger asthma attacks or make breathing more difficult in general.
- Neurological effects: Some, such as benzene, toluene and organic solvents, can have toxic effects on the central nervous system, causing symptoms such as dizziness, headaches, confusion, memory loss and, in severe cases, neurological damage.
- Liver and kidney problems: Prolonged or repeated exposure to certain VOCs, such as carbon tetrachloride, can damage the liver and kidneys and interfere with their normal function.
- Carcinogenic effects: Some VOCs, such as benzene, formaldehyde and vinyl chloride compounds, have been linked to an increased risk of cancer in epidemiological studies and animal experiments.
It is important to mention that these compounds are fat-soluble, which means that they bioaccumulate in the fat of living organisms. In the long term they can cause kidney, liver or central nervous system damage and some have a carcinogenic effect, such as benzene.
Sources of volatile organic compounds
There are many sources of volatile organic compounds (VOCs) in our environment. They are usually found in cleaning products, building materials, furniture, personal care products, etc.
Among the building, furniture and decoration materials that emit VOCs, we can mention: plasterboards, ceiling panels, pressed wood elements, rubber or cement joints, sealants, melamine panels, paints, many adhesives, wallpapers, wallpaper glues, carpets, wooden floors, upholstery and curtains… while cleaning products are the most common VOC emitters. … while cleaning products and cosmetics include soaps, gels, varnishes, perfumes and detergents, window cleaners, stain removers, degreasers, polishes, pesticides, aerosols, etc.
The VOC emission of all these materials decays over time, but very unevenly: while wet materials that dry within hours of application tend to emit heavily in the wet phase, only to cease or greatly reduce their emission once dry, solid materials peak in emission when removed from the packaging, only to gradually decompose over time.
However, they can maintain significant emission levels for months or even years after installation. The emission intensity after months or years of installation varies greatly from one material to another.
The importance of measuring volatile organic compounds
Being able to monitor the different concentrations that can accumulate in an indoor space is essential for assessing indoor air quality, since, as we have seen, there are many everyday sources of emissions that increase VOC concentrations.
It is therefore important to have an indoor air quality device with a VOC sensor that can alert when VOC levels are too high and therefore harmful to health.
A simple and effective method of detection that allows decisions to be made about the ventilation of indoor spaces and thus eliminate the emissions that may be produced.
