Everything to know about Volatile Organic Compounds (VOCs)
Volatile organic compounds (VOCs) are a group of organic chemical substances emitted into the air from various products and processes in both indoor and outdoor environments. Despite them not being included in many standard air quality guidelines, such as the World Health Organization’s, we at Breeze Technologies consider it vital to be monitored. Our sensors are thus calibrated to measure volatile organic compounds, and it is found in both our indoor and outdoor air quality indexes (AQI) due to their impact on air quality and human health. Read on to find out more.
What are volatile organic compounds?
Volatile organic compounds refer to a large group of carbon-containing substances including hydrocarbons, alcohols, aldehydes, and organic acids but excluding carbon dioxide, carbonic acid, metallic carbides, carbonates, and ammonium carbonate. Their composition makes it possible for them to evaporate under normal atmospheric conditions of temperature and pressure. The European Union (EU) thus defines VOCs as any organic compound with an initial boiling point that is less than or equal to 250°C at an atmospheric pressure of 101.3 kPa.
Distinctions are drawn between VOCs, very volatile organic compounds (VVOCs), and semi-volatile organic compounds (SVOCs). The sum of the concentrations of all VOCs gives the TVOC value (total volatile organic compounds), which is what is used in Breeze Technologies’ indoor air quality index (AQI).
Below is a table detailing the classification of VOCs:
|Description||Boiling Point Range (°C)||Example Compounds|
|Very volatile organic compounds (VVOC)||<0 to 50-100||Propane, butane, methyl chloride|
|Volatile organic compounds (VOC)||50-100 to 240-260||Formaldehyde, d-Limonene, toluene, acetone, ethanol (ethyl alcohol) 2-propanol (isopropyl alcohol), hexanal|
|Semi-volatile organic compounds (SVOC)||240-260 to 380-400||Pesticides (DDT, chlordane, plasticizers (phthalates), fire retardants (PCBs, PBB)|
In addition, there is a specific term for VOCs that do not contain methane, which is non-methane volatile organic compounds (NMVOCs). They have an even higher aspiration to combine with nitrogen dioxide (NO2) to form ground level ozone (O3) and contribute to the formation of secondary particulate matter (PM2.5).
VOCs are also a major component of photochemical smog when it reacts with sunlight and nitrogen oxides (NOx) in the atmosphere.
What are sources of volatile organic compounds?
Volatile organic compounds are volatilized or released into the atmosphere outdoors by incomplete combustion processes, using everyday products and materials, as volatile commercial and industrial byproducts, and through biological processes (plant metabolism, putrefaction, and decomposition).
Below is a list of common urban VOCs and their characteristic sources:
|Compound||Approximate Atmospheric Lifetime||Sources|
|Ethane||1.5 months||Natural gas, biomass burning|
|Acetylene||15 days||Vehicle emissions, biomass burning|
|Methanol||12 days||Plants, VOC oxidation|
|Propane||11 days||Liquefied petroleum gas, natural gas|
|Benzene||10 days||Industrial emissions, vehicle emissions, biomass burning|
|Isobutane / N-butane||5 days||Vehicle emissions, liquefied petroleum gas|
|Ethanol||4 days||Plants biofuel|
|Isopentane / N-pentane||3 days||Vehicle emissions, gasoline evaporation|
|Toluene||2 days||Solvents, vehicle emissions|
|Ethene||1 day||Vehicle emissions|
|Formaldehyde||1 day||VOC oxidation, biomass burning|
VOCs are particularly concentrated indoors due to internal sources from interior products and building materials that contain them. These include:
- Paints, paint strippers, and other solvents
- Lacquers, varnishes, and wood preservatives
- Caulks and sealants
- Cleaners and disinfectants
- Aerosol sprays
- Air fresheners
- Cosmetics and deodorants
- Tobacco smoke
- Flame retardants
- Stored fuels and automotive products
- Moth repellents
- Dry-cleaned clothing
- Hobby supplies
- Graphics and craft materials (glues, adhesives, permanent markers, photographic solutions)
- Office equipment (copiers, printers, correction fluids, carbonless copy paper)
What is the health impact of volatile organic compounds?
Many VOCs have been shown to have toxic, carcinogenic, mutagenic, genotoxic, and teratogenic effects on humans. While individual VOC levels tend to be moderate with no expected health effects, concentrations rise to concerning levels after construction works and renovations. As such, the indoor impact of VOCs has greater health implications since people spend time predominantly in buildings. In fact, the concentrations of some air pollutants can be between 2 to 10 times higher indoors than outdoors.
Health effects of VOC exposure include:
- Eye, nose, and throat irritation
- Nausea and vomiting
- Shortness of breath
- Damage to liver, kidneys, and central nervous system
- Cancers (leukemia and lymphoma)
In addition, poor indoor air quality as a result of high VOC levels is linked to a phenomenon known as “Sick Building Syndrome”, which cause flu-like symptoms such headaches, dry cough, fever, chills, chest tightness, dry or itchy skin, dizziness, nausea, difficulty concentrating, fatigue, and sensitivity to odours. However, these symptoms usually subside once the individual leaves the building.
What is the environmental impact of volatile organic compounds?
As mentioned earlier, especially NVMOCs are capable of generating ground level ozone (O3) and secondary particulate matter (PM2.5). O3 is capable of reducing crop and forest yields, increasing climate warming, and impacting evaporation rates, cloud formation, precipitation levels, and atmospheric circulation. PM2.5 can damage forests, farm crops, and building materials, contribute to global warming, and influence cloud formation and rainfall patterns. All this affects both ecosystems and human livelihoods.
How can volatile organic compound emissions be lessened?
When it comes to outdoor (urban) pollution, the best way to reduce VOC emissions are:
- Vehicle emission control technologies (catalytic converters)
- Vehicle emission, fossil fuel, and biomass reduction strategies
- Fuel substitution (from diesel to liquified petroleum gas, compressed natural gas, electricity)
For indoor air quality, it is best to ensure good ventilation and monitor air pollutant levels aside from buying and using low VOC-emanating products. Breeze Technologies offers a fully-digital solution for air quality monitoring, management and improvement for the workplace to secure employee health and productivity. We provide data- and AI-based recommendations for clean air actions, such as:
- Modifying and maintaining heating, ventilation, and air conditioning (HVAC) systems to increase air distribution and flow
- Installing air cleaners/purifiers/filters
- Identifying and replacing interior pollution sources such as flooring, machinery, and upholstery
Contact us today for more information!