Organic Compounds are chemicals that contain carbon and are found in all living things. Now Volatile organic compounds (VOCs) are organic compounds that easily become vapors or gases. That means VOCs have a low boiling point which causes large numbers of molecules to evaporate or sublimate from the solid or liquid form of the compound. Do you remember the distinctive smell of plastic, rubber or leather? That what you smell or VOCs. Over the last decades there was a lot of discussion going on to the topic farmaldehyde (methanal) a VOC which evaporates from paint and has a boiling point of only -19 deg C or -2 deg F. A major source of man-made VOCs are coatings, especially paints and protective coatings. Solvents are required to spread a protective or decorative film. Approximately 12 billion liters of paints are produced annually. But also the use of fossil fuels produces VOC’s either directly or indirectly as byproducts (e.g. automobile exhaust gas).
Since many people spend much of their time indoors and a long-term exposed to VOCs in the indoor environment it can contribute to sick building syndrome. In offices, also office equipment such as photocopy machines, can off-gas VOCs into the air. Studies also show that relative leukemia and lymphoma can increase through prolonged exposure of VOCs in the indoor environment.
Respiratory, allergic, or immune effects in infants or children are associated with man-made VOCs and other indoor or outdoor air pollutants.
Health effects include eye, nose, and throat irritation; headaches, loss of coordination, nausea; damage to the liver, kidney, and central nervous system. Some VOCs can cause even cancer. Key signs or symptoms associated with exposure to VOCs include conjunctival irritation, nose and throat discomfort, headache, allergic skin reaction, dyspnea, declines in serum cholinesterase levels, nausea, vomiting, nose bleeding, fatigue, dizziness.
At present, not much is known about what health effects occur from the levels of organics usually found in homes. Many organic compounds are known to cause cancer in animals; some are suspected of causing, or are known to cause, cancer in humans.
And remember outdoor VOCs in combination with nitrogen + energy produces “bad” ozone!
Benzene
One VOC that is a known human carcinogen is benzene, which is a chemical found in environmental tobacco smoke, stored fuels, and exhaust from cars. Benzene also has natural sources such as volcanoes and forest fires. It is frequently used to make other chemicals in the production of plastics, resins, and synthetic fibers. Benzene evaporates into the air quickly and the vapor of benzene is heavier than air allowing the compound to sink into low-lying areas. Benzene has also been known to contaminate food and water and if digested can lead to vomiting, dizziness, sleepiness, rapid heartbeat, and at high levels, even death may occur.The aromatic VOC benzene emitted mainly from exhaled cigarette smoke but it might be also emitted from building material (paints or adhesives) and from burning fossil fuel. It is proven that benzene levels are higher in houses with a detached garage or houses located close to petrol stations.
Health effect: Benzene is a well-established cause of cancer in humans. The International Agency for Research on Cancer has classified benzene as carcinogenic to humans (Group 1). Benzene causes acute myeloid leukemia (acute non-lymphocytic leukemia), and there is limited evidence that benzene may also cause acute and chronic lymphocytic leukemia, non-Hodgkin’s lymphoma and multiple myeloma. Individuals who have experienced benzene poisoning requiring treatment show a substantially increased risk of mortality from leukemia. Chronic exposure to benzene can reduce the production of both red and white blood cells from bone marrow in humans, resulting in aplastic anemia. Both B-cell proliferation and T-cell proliferation are reduced by benzene. Decreased host resistance to infection has been reported in several laboratory animals exposed to benzene. However, other measures of immunotoxicity have not been studied.
Chromosomal aberrations in human peripheral lymphocytes are associated with occupational exposure to benzene. Chromosomal aberrations, micronuclei, sister chromatid exchange and sperm head abnormalities have been seen in laboratory species treated in vivo. Chromosomal aberrations and mutations were seen in human cells in vitro and in laboratory animal cells in some in vitro studies.
Benzene is fetotoxic in mice and rabbits following maternal exposure by inhalation, causing a reduction in birth weight. It is not, however, teratogenic in experimental animals, even at maternally toxic doses.
Benzene maximum exposure for humans is set to 5 µg/m3 per year
VOC’s can also be produced by microorganisms such as fungi and bacteria. Most of us will remember the typical smell of mold and what we smell here are Microbial Volatile Organic Compounds (MVOC’s) which are composed of low molecular weight alcohols, aldehydes, amines, ketones, terpenes, aromatic and chlorinated hydrocarbons, and sulfur-based compounds, all of which are variations of carbon-based molecules. Microbial Volatile Organic Compounds (MVOC’s) have a very low odor threshold, thus, making them easily detectable by smell. They often have strong odors and are responsible for the odious smells (“old cheese”, dirty socks” or “locker room”) associated with mold and bacterial growth.
MVOC’s are products of the microbes’ primary and secondary metabolism. Information on bacterial MVOC’s produced in indoor settings is limited. Studies conducted on a few bacteria, such as the actinomycetes Streptomyces griseus and Streptomyces odorifer show that they can produce geosmin, 2-methyl -isoborneol, and 3-methyl-butanol.