Volatile Organic
Compounds (VOC's)
Environmental Sources
Volatile Organic Compounds (VOC's) are organic (carbon-containing) chemicals
that have a high vapours pressure and easily form vapours at normal temperature
and pressure. VOC’s include trichloroethylene,
benzene, toluene,
styrene, acetone,
ethyl benzene, mixed
xylenes methyl ethyl ketone, alcohols, methacrylates, acrolein, polycyclic
aromatic hydrocarbons, and pesticides. VOC's are a by-product of fossil
fuel combustion and come from many sources including industrial and combustion
processes and petrol stations. The use of organic solvents,
certain paint additives, aerosol spray can propellants, fuels (such as
petrol, and paraffin), petroleum distillates, dry cleaning products and
many other industrial and consumer products ranging from office supplies
to building materials contribute to VOC emissions. Most
VOC's contribute to the formation of ground level ozone.
Human Health effects
When the central nervous system is primarily affected, symptoms can include
diminished cognition, memory, reaction time, and hand-eye and foot-eye
coordination, and balance and gait disturbances. Exposure can also lead
to mood disorders, with depression, irritability, and fatigue being common
symptoms. Peripheral neurotoxicity usually results in paresthesias, tremors,
and diminished fine and gross motor movements. VOCs have been implicated
in kidney damage. They have been associated with immunological problems,
including increased cancer rates and immunotoxicity. The typical presentation
of low-dose formaldehyde exposure includes upper respiratory irritations
(rhinitis, sinusitis, pharyngitis), lower respiratory symptoms of wheezing,
and persistent flu-like symptoms.
Exposure limits
The exposure limits to VOC’s vary from chemical to chemical. Refer to
trichloroethylene, benzene,
toluene, styrene,
acetone, ethyl benzene
and mixed xylenes for their individual
exposure limits.
Sources & Links :
www.epa.gov/iaq/voc.html
www.thorne.com/altmedrev/fulltext/envmed5-2.html
www.epa.gov/children/
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