What are VOCs?

Volatile organic compounds (VOCs) are chemical compounds emitted as gases from solids or liquids. 

VOCs are volatile because they easily evaporate at room temperature and are organic compounds because they include carbon. VOCs are wide-ranging and have varying levels of toxicity. 

What are some examples of VOCs?

A partial list of notable toxic VOCs includes: 1,2,3

  • acetone
  • benzene
  • formaldehyde
  • styrene
  • tetrachloroethylene
  • toluene
  • xylene

Methane is an organic compound and is listed as a VOC by some government environmental regulatory agencies.4 However, regulatory agencies separate methane from other VOCs for several reasons:

  • low photochemical reactivity
  • doesn’t contribute as much to the formation of ground-level ozone as other VOCs
  • provides a strong direct contribution to climate change

Where do VOCs come from?

VOCs are emitted from a wide array of sources, partially varying due to geography. Cities see their largest contributions from vehicle emissions, while industrial and suburban sources may come more from fossil fuel burning and waste emissions.5

VOC emissions are a concern for all nations. For example, a 2018 study published in Atmospheric Environment found that open burning of maize crop residue resulted in 79 tons of VOC emissions in northern Thailand.6   

In Delhi, India, 80 percent of VOCs in the city’s air came from traffic emissions and solid fuel burning.7

The top ten industrial emitters of VOCs in Canada during 2017 contributed a combined 61,000 tons of VOCs into the atmosphere primarily through oil extraction and refining as well as through alcohol brewing. 8 

VOC sources include:9,10

  • paints
  • aerosol sprays
  • printing inks
  • cleaning products
  • wood preservatives
  • cleansers and disinfectants
  • building materials
  • feedstock
  • home firewood burning
  • oil and gas industry
  • fuel
  • bacteria
  • propane
  • ethanol
  • butane
  • mineral spirits 

Vehicle fuel combustion is an important source of VOCs. However, VOCs aren’t solely from vehicle tailpipes: toxic VOCs can be emitted through off-gassing chemicals inside car interiors.

Pleasant-smelling products can actively emit VOCs. For instance, the “new car smell” experienced during a new vehicle purchase is an example of interior car parts off-gassing.11 Research conducted by the non-profit Ecology Center determined that there was a cocktail of hundreds of toxic chemicals that off-gas within car interiors. 

Car air fresheners and home air fresheners emit VOCs.12 A 2011 study published in Environmental Health Perspectives found that over 100 VOCs were emitted by scented consumer goods.

Scented candles have been found to negatively influence indoor air quality as they emit VOCs even when unlit.13  A 2015 study published in the Journal of Hazardous Materials found that though the composition of VOCs differed depending upon whether scented candles were lit or unlit, scented candles were strong indoor sources of VOC emissions in either state.
 
Indoor concentrations of VOCs are on average 2-5 times higher than outdoors.14 VOC concentrations can be higher indoors due to inadequate ventilation, higher temperatures and humidity than the outdoors, and outdoor weather encouraging reduced natural ventilation and reduced airflow. 

How do VOCs affect your health?

VOCs can vary greatly in their composition: some VOCs, such as benzene (a known carcinogen), are highly toxic. Like other pollutants, VOCs can create serious health concerns depending on an individual’s length of exposure.

Short-term effects include:15

  • irritation of eyes, nose, throat
  • headaches
  • breathing problems

Long-term health impacts can include:16,17,18

  • sick building sickness
  • allergies and asthma
  • cancer
  • kidney damage

VOCs may affect cardiovascular function. A 2015 study published in Atmospheric Environment indicated that some VOC types were associated with elevated heart rate and had a negative impact on the brachial arteries.19

By contributing to the formation of ozone and PM2.5, VOCs also indirectly contribute to the significant health effects of both of these pollutants.

What are the environmental effects of VOCs?

VOCs play a significant role in the formation of ozone and PM2.5, both of which contribute to creating smog. VOCs and nitrogen oxides act as precursors which, under sunlight, react to create ozone and PM2.5, significantly contributing to urban outdoor air pollution.

In contributing to the formation of ozone, VOCs indirectly damage plant life, including decreased crop yields and increased plant susceptibility to disease.

Are VOCs greenhouse gases?

VOCs are not a significant direct contributor to greenhouse gases. Instead, VOCs are considered indirect greenhouse gases because they contribute to climate change indirectly through chemical processes.20  

VOCs and nitrogen oxides react with sunlight to create tropospheric ozone, or ground-level ozone. Tropospheric ozone is the third most important greenhouse gas after carbon dioxide and methane because ozone absorbs the sun’s radiation and raises the temperature.   

What can be done to reduce VOCs in your environment?

To protect yourself from indoor concentrations of VOCs, minimize the number of VOC sources in your home. There are several ways to reduce your VOC exposure, such as:21,22

  • use air-tight containers to store VOC-containing products
  • keep chemicals with VOCs in them away from people in a garage or shed if possible
  • dispose of unused chemicals through your community’s household hazardous waste collection system
  • try not to purchase aerosol consumer products
  • purchase water-based paints rather than solvent-based 
  • renovate the home when it is unoccupied if possible
  • when driving, use a car air purifier like the Atem Car

A VOC-specific air purifier like the GC series can be configured by filter to eliminate VOCs and clean the air. You can also keep windows open and ventilate the indoor environment with fresh air to dilute and lower VOC concentrations.

City and rural pollutants have a real impact on the world’s citizens, both in lives lost and in economic sustainability. Despite air quality improvements through regulations, the cost of air pollution is high in too many nations. Check out our Cost of Air Pollution counter and uncover how clean air can help preserve health and life while alleviating harm to the global economy.