Total Volatile Organic Compounds (TVOC) are a group of compounds containing carbon that have a high vapour pressure present in the air. There are abundant VOC emitted from everyday activities among which some are colourless and some odourless and some are toxic. TVOC monitoring is an efficient way to detect exposure to toxic VOCs. This article covers information on total volatile organic compounds, their sources in the ambient air, characteristics, health and environmental impact, possible corrective measures, need for TVOC monitors as well as different methods of TVOC monitoring. What is TVOC? Volatile organic compounds (VOC) are a group of compounds containing carbon that have a high vapor pressure i.e. easily convert into vapor or gases and have low water solubility. There are thousands of VOCs in the environment however, some may have short- and long-term adverse health effects when exposed to. The principal VOCs of interest include benzene, toluene, formaldehyde, ethylbenzene (BTEX), xylene, acetaldehyde, ethylene glycol, methylene chloride, acetone, styrene, etc. [Source: https://ere132.com/en/learn/for-a-healthy-home/volatile-organic-compounds-vocs.php] There are a large number of VOCs present in the environment making it difficult to continuously monitor them simultaneously. Hence, a common term TVOC (Total Volatile Organic Carbon) is used representing the total concentration of VOCs present in the air. Such a common term of measurement makes it easier to determine the overall presence of VOC and is cheaper than measuring individual VOCs. TVOC in Atmosphere We are in continuous contact with several products that contain and/or emit VOCs like disinfectants, paints and varnishes, solvents, semiconducting materials, rubber, vehicle exhaust, fuel, ink, adhesives, etc. Each VOC has its characteristic signature. For example, due to combustion, vehicle exhaust emits ethene while broadleaf trees emit isoprene. Different VOCs have different reaction rates and hence, have a large range of transport distances ones emitted. VOCs that have low creativity remain in the atmosphere for large durations of time are known as Persistent Organic Pollutants (POPs) and some VOCs are known as Hazardous Air Pollutants (HAPs) because of their toxicity.

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Total Volatile Organic
Compound (TVOC)
All you need to know about...

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All you need to know about TVOCWHAT IS TVOC?
There are thousands of VOCs in the environment, some of
which may have short- and long-term adverse health effects.
Principal VOCs are benzene, toluene, formaldehyde,
ethylbenzene (BTEX), xylene, acetaldehyde, ethylene glycol,
methylene chloride, acetone, styrene, etc.
Their abundance makes it difficult to continuously monitor
them simultaneously. Hence, a common term “TVOC” (Total
Volatile Organic Compound) is used representing the total
concentration of VOCs present in the air.
Volatile organic compounds (VOC) are a group of compounds containing carbon that
have a high vapor pressure i.e. easily convert into vapor or gases and have low water
solubility.

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All you need to know about TVOCSOURCES
Natural Sources: forests, oceans, termites, wetlands, and
volcanoes.
Anthropogenic / Industrial Sources:
● Vehicular emissions
● Production, storage, and burning of fossil fuels such as
gasoline, wood, coal, or natural gas
● Industrial processes in the chemical, petrochemical,
automotive, and pharmaceutical sectors
● Petroleum handling, Oil refining, Bio decomposition
● Materials such as paint, varnishes, sealants, adhesives,
cleaners, disinfectants, furniture, pesticides, air fresheners,
cosmetics, deodorants, printing inks, flooring, tobacco
smoke, etc

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All you need to know about TVOCTVOC in Atmosphere
TABLE - Some common VOCs found in urban atmospheres with their characteristic
sources and approximate lifetime in the ambient air
Compound
Atmospheric lifetime
(approx)
Characteristic Sources
Ethane 1.5 months Natural gas, biomass burning
Acetylene 15 days Vehicular emission, biomass burning
Methanol 12 days Plants, VOC oxidation
Propane 11 days Liquified Petroleum Gas (LPG), Natural gas
Benzene 10 days Industrial emissions, vehicle emissions, biomass burning
iso/n-Butane 5 days Vehicular emissions, LPG
Ethanol 4 days Plants, biofuel
iso/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
Isoprene 3 hours Plants
Source: World Meteorological Organization, Bulletin no.- Vol 68 (2) - 2019

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All you need to know about TVOCADVERSE IMPACTS
HEALTH IMPACTS OF TVOC
SHORT TERM EFFECTS
● Headache
● Irritation in Eye, Nose and
Throat
● Fatigue, dizziness
● Nausea, vomiting
● Coughing, difficulty in
breathing
● Allergic skin reactions
● Visual disorders
● Memory impairment
● Pneumonia, Bronchitis
LONG TERM EFFECTS
● Damage central nervous
system
● Chronic respiratory
disease (asthma)
● Cardiovascular diseases
● Cancer
● Damage liver
● Damage kidney
● Impact reproductive
system

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All you need to know about TVOCADVERSE IMPACTS
ENVIRONMENTAL IMPACTS OF TVOC
● VOCs result in the formation of secondary
air pollutants such as ozone, smog and
fine particulate matter which in turn have
their own adverse effects on human health
and environment.
● VOCs in the atmosphere react with another
primary pollutant NOx, in the presence of
sunlight to form ozone (O3) and fine
particulate matter (PM2.5). The accumulation
of O3, PM2.5, and other air pollutants in the
atmosphere results and smog formation
and visibility reduction.

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All you need to know about TVOCCORRECTIVE MEASURES
The primary action is TVOC monitoring i.e. to measure how much of TVOC concentrations
you are exposed to. In addition to this following corrective measures can be taken:
● Avoid staying in poorly ventilated areas for long durations.
● Promote the use of alternative fuels and improve quality fuels with high emission
rates.
● Avoid keeping your vehicle idle for long.
● Avoid areas with traffic congestions. Breathing such polluted air daily also leads to
health effects in the long run.
● Limit outdoor activities and close windows and vents during times of high air
pollution.
● Avoid or Limit using VOC- containing products such as organic cleaning solvents.

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All you need to know about TVOCMONITORING METHODS
Photoionisation detection (PID)
The air sample drawn into the TVOC
monitor is exposed to UV light of a
specific output that excites the VOC
molecules present in the air sample.
The molecules become electrically
charged as it ionizes everything that has
an ionization energy less than or equal to
the UV lamp output.
The ions produce an electric current proportional to the concentration of TVOC and are
measured by the detector.

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All you need to know about TVOCMONITORING METHODS
Flame ionization detection (FID)
TVOC monitors based on the principle of FID works
similar to the PID based TVOC monitors. FID uses a
hydrogen flame to ionize all the hydrocarbons present in
the sample air. The ions produced are proportional to the
TVOC concentration in the sample air which is detected
by the detector.
Semiconductor
When sensor is exposed to air sample, the TVOC
molecules react on the metal oxide surface of the sensor
and dissociate into charged ions which alter the
resistance of the film which is measured and converted
to the TVOC concentration.

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All you need to know about TVOCOIZOM’S PRINCIPLE
Oizom’s ODOSENSE is the real-time odour
emission tracking solution. It continuously
detects, measures and monitors the odourful
gaseous contaminants including H2S, NH3, SO2,
CH3SH, TVOC, CH2OH, and weather parameters
like temperature, humidity, wind speed, and wind
direction.
The sensor that measures TVOC work on the
principle of Photoionisation detection (PID).
Real-time monitoring of TVOC levels helps in
determining their source as well as formulating an
action plan to control VOC emissions.