Standard particulate matter particle pollution air pollution and control particulate matter Monitoring of Particulate matter Monitoring of air pollutants

1. Monitoring of SPM
Ravi Kumar GARRE

2. Contents covered
• Filtration
• Sedimentation
• Impingement
• Impaction
• Electrostatic precipitation
• Thermal precipitation

3. Filtration
• Filtration of polluted air is a convenient
method to remove the particulate matter in it.
• The filters used for this purpose are generally
made up of fibrous substances.
• They have the ability to remove larger
particles to fine particles with high efficiency.
• The instrument used to collect particulate
matter of size less than 0.1 micron in size

4. Sedimentation
• The coarse settleable particulate matter of
size greater than 10 microns in diameter can
settle out under the influence of gravitational
force.
• The dust fall jar/ container is preferred device
for collection of bigger particulates.

5. Impingement
• In this method the particulates in the high velocity air
stream is made to collide with an obstacle in an
impinger so that the air stream is deflected after
striking the obstacle.
Dry impinger:
• The particulates in the high velocity air stream strike
the obstacle which is a solid with adhesive surface.
Wet impinger:
• In this type, the particulates in the high velocity air
stream strike the obstacle placed in a liquid so that the
particulates are trapped in the liquid medium.

6. Impaction
• Impactors are the devices in which air is forced to pass
through small holes and strike against another solid surface
plate with smaller holes.
• A cascade impactor consists of several such plates with
progressive decrease in the size of holes.
• The air stream passing through each plate impinges at an
increased velocity.
• The coarse particulate matter is separated at the first stage
and the finer particles are separated at a later stage.
• The particulate matter deposited at each stage is collected
and the total weight and chemical composition is
determined.

7. Electrostatic precipitation
• Electrostatic precipitators (ESPs), also known as
electrostatic air cleaners.
• These are special devices used in general air cleaning
system in industrial operations which produce exhaust
gases containing dust, fly ash, fumes and mist.
• They are so called because electrostatic forces separate
the dust particles from the exhaust gases.
• Such devices are efficient enough to collect particles in
size range of 0.1 microns to 10 microns.

8. Thermal precipitation
• This involves the use of thermal gradient to collect the
particulate matter.
• The device thermal precipitator consists of two
adjacent surfaces with a strong temperature gradient.
• The air stream is made to flow in between the two
surfaces at slow rate of 10 to 25 ml/minute.
• The particulate matter in air gets deposited on the
colder region of the plates.
• The accumulated particulates in the collection area is
sent for further microscopic analysis for the number of
particles and morphological characteristics.

9. Thank you