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Addition of Benzene in Petrol in place of Tetra Ethyl Lead is
resulting emission of Benzene and its compounds in vehicular
exhaust. As a results Benzene concentrations in urban
atmosphere having significant traffic, has become a matter of
concern.
Benzene concentrations near industries handling organic
compounds such as refineries pharmaceutical and chemical
units are also showing rising trends. Dry cleaning, gasoline
handling, fuel burning and waste incineration are some known
major sources of emission existing in urban environment affects
ambient levels of these compounds
Organic compounds including Benzene being pre-cursers for
Ozone formation and also play a key role, in formation of
secondary pollutants.
Benzene is toxic & carcinogenic found causing serious health
impacts hence it has been included as parameter for regular
monitoring in new air quality standard notified by MOEF in
November 2009.
As such Air Pollution Monitoring networks in many cities and
close to relevant industrial activities are now putting intensive
efforts for monitoring of Benzene. Bureau of Indian Standards
(BIS) has also published Air Quality Standard method for
measurement of Organic compounds in ambient air(BIS
5182(Part 11)).
To meet Benzene monitoring requirements as mentioned in
the standard, Ecotech has developed a Benzene sampler
model AAS172 to collect samples of Benzene present in
ambient air.
Benzene is adsorbed in an activated charcoal cartridge. The
contents of the tube are removed from the glass tube after
sampling for desorption. The tubes can be re-packed with
fresh activated charcoal for re-use.The adsorbed benzene is
thermally or chemically desorbed, can be analyzed using Gas
Chromatograph to found out the its concentration in ambient
air.
The AAS172 uses a Flow-meter to accurately measure low
flow rates in the range of 0 to 200 ml/min. Low flow rate allows
the user to collect a representative composite sample over several hours without fear of sample loss due
to saturation or breakthrough. The Ecotech AAS172 has a power operated light weight diaphragm pump
suitable for long sampling durations. A Time Totalizer fitted in the sampler give actual time of sampling.
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