Volatile organic compound
They play an important role in communication between animals and plants, such as attractants for pollinators, protection from predation, and even inter-plant interactions.
The high vapor pressure of VOCs correlates with a low boiling point, which relates to the number of the sample's molecules in the surrounding air, a trait known as volatility.
[8] The European Union defines a VOC as "any organic compound as well as the fraction of creosote, having at 293.15 K a vapour pressure of 0.01 kPa or more, or having a corresponding volatility under the particular conditions of use;".
The People's Republic of China defines a VOC as those compounds that have "originated from automobiles, industrial production and civilian use, burning of all types of fuels, storage and transportation of oils, fitment finish, coating for furniture and machines, cooking oil fume and fine particles (PM 2.5)", and similar sources.
The CARB revised the definition of "Volatile Organic Compounds" used in their consumer products regulations, based on the committee's findings.
[7] Biogenic volatile organic compounds (BVOCs) encompass VOCs emitted by plants, animals, or microorganisms, and while extremely diverse, are most commonly terpenoids, alcohols, and carbonyls (methane and carbon monoxide are generally not considered).
[26] Due to recent climate change developments, such as warming and greater UV radiation, BVOC emissions from plants are generally predicted to increase, thus upsetting the biosphere–atmosphere interaction and damaging major ecosystems.
Examples include: paints, varnishes, waxes and lacquers, paint strippers, cleaning and personal care products, pesticides, building materials and furnishings, office equipment such as copiers and printers, correction fluids and carbonless copy paper, graphics and craft materials including glues and adhesives, permanent markers, and photographic solutions.
Existing buildings may be replenished with new VOC sources, such as new furniture, consumer products, and redecoration of indoor surfaces, all of which lead to a continuous background emission of TVOCs, and requiring improved ventilation.
[45] For quality control of these measurements round robin tests are carried out, therefore reproducibly emitting reference materials are ideally required.
Respiratory, allergic, or immune effects in infants or children are associated with man-made VOCs and other indoor or outdoor air pollutants.
[57][58] Health effects include eye, nose, and throat irritation; headaches, loss of coordination, nausea, hearing disorders[59] and damage to the liver, kidney, and central nervous system.
As with other pollutants, the extent and nature of the health effect will depend on many factors including level of exposure and length of time exposed.
Eye and respiratory tract irritation, headaches, dizziness, visual disorders, and memory impairment are among the immediate symptoms that some people have experienced soon after exposure to some organics.
Dermal exposure to VOCs like formaldehyde and toluene downregulate antimicrobial peptides on the skin like cathelicidin LL-37, human β-defensin 2 and 3.
[66][69] Limit values for VOC emissions into indoor air are published by AgBB,[70] AFSSET, California Department of Public Health, and others.
These regulations have prompted several companies in the paint and adhesive industries to adapt with VOC level reductions their products.
[75] Other healthcare environments such as nursing and age care homes have been rarely a subject of study, even though the elderly and vulnerable populations may spend considerable time in these indoor settings where they might be exposed to VOCs, derived from the common use of cleaning agents, sprays and fresheners.
The health effects include skin sensitization, reproductive and organ-specific toxicity, carcinogenicity, mutagenicity, and endocrine-disrupting properties.
[80] Workers in hospitality are also exposed to VOCs from a variety of sources including cleaning products (air fresheners, floor cleaners, disinfectants, etc.
[81] Housekeepers in particular may also be exposed to formaldehyde,[82] which is present in some fabrics used to make towels and bedding, however exposure decreases after several washes.
VOCs present in cleaning supplies can cause skin, eye, nose, and throat irritation, which can develop into dermatitis.
[89] One study found that VOC concentrations were higher in retail storage spaces compared to the sales areas, particularly formaldehyde.
One study found that workers were exposed to peak total VOC concentrations when they were removing the plastic film off of new products.
Furthermore, collection of VOCs by condensation in cold traps also accumulates a large amount of water, which generally must be removed selectively, depending on the analytical techniques to be employed.
[97] PTR-MS instruments based on time-of-flight mass spectrometry have been reported to reach detection limits of 20 pptv after 100 ms and 750 ppqv after 1 min.
[99] One study has shown that "volatile organic compounds ... are mainly blood borne and therefore enable monitoring of different processes in the body.
"[100] And it appears that VOC compounds in the body "may be either produced by metabolic processes or inhaled/absorbed from exogenous sources" such as environmental tobacco smoke.
For a number of VOCs gaseous reference standards are available from specialty gas suppliers or national metrology institutes, either in the form of cylinders or dynamic generation methods.
[44] The final scopes are for the traceability and the long-term stability of the standard gases to be in accordance with the data quality objectives (DQO, maximum uncertainty of 20% in this case) required by the WMO/GAW program.
