The document provides a detailed explanation of particulate matter (PM), its sources, classification, and effects on health and the environment. It categorizes PM based on size (coarse and fine particles) and origin (natural or man-made), discussing their health impacts and the regulatory measures in place for controlling emissions in industrialized countries. Various dust collection systems used to manage PM emissions, including inertial collectors, fabric filters, wet scrubbers, and electrostatic precipitators, are also described.

1. BY: MARIA ARSHAD
YOU TUBE CHANNEL: Chemistry Philics
Lets make chemistry easy and loveable by having strong concepts
PART-3
Explained in detail for BSM.Sc students

2.  DEFINITION:
 “The microscopic solid or liquid
matter suspended in the earth’s atmosphere
is known as particulate matter”
 The sources of particulate matter may be
 man made or natural

3.  Atmospheric aerosols are solid or liquid
particles smaller than 100µm in diameter
 Pollutant particles in the 0.001 to 10µm range
are commonly suspended in the air near the
sources of pollution i.e industrial
plants,highways etc
 Very small solid particles i.e carbon
black,silver iodide,combustion nuclei
 Large particles e.g cement,dust etc
 Liquid particulate matter:mist,fog,H2SO4 mist
 Particles of biological origin:bacterial spore etc


4.  The composition of PM depends on source
 Classification:
1) Wind blown mineral dust
2) seasalt
3) Secondary particles
4) Organic matter
1) WIND BLOWN MINERAL DUST:
 Made up of mineral oxides and
material blown from earth crust
 This particulate is light absorbing

5.  2) SEASALT:
 Mainly consists of NaCl,
 depending on the composition of sea water
they include
magnesium,sulfate,calcium,potassium,O.C etc.
 3) SECONDARY PARTICLES:
 Derive from the oxidation of primary gases
i.e SO2 and Nox into H2SO3 and HNO3
 In presence of NH3 they take the form of
ammonium salt i.e ammonium
sulphate,ammonium nitrate
 In the absence of NH3 take acidic form of
acids. Both forms are dangerous.
 This particulate is light scattering.

6.  4) ORGANIC MATTER:
 can be primary or secondary(from the
oxidation of VOCs)
 it may be biogenic or anthropogenic
 this particulate is light
absorbing+scattering
 Elemental Carbon also known as black
carbon is another important aerosol type and
is strongly light absorbing
 Secondary organic aerosols,tiny “tar balls”
resulting fromcombustion products of
internal combustion engines
 Dangerous to health

7.  The chemical composition of aerosol directly
effects how it interacts with solar radiation
 the chemical constituents change the overall
refractive index.
 The refractive index will determine how much
light is scattered and absorbed.
 The composition generally causes the visual
effects

9.  Classification of PM on the basis of sizes

10.  COARSE PARTICLES:
 SIZE 2.5-10µm also known as PM10
 usually contain earth crust’s materials
and dust from roads and industries,pollen etc
 FINE PARTICLES:
 SIZE ≤2.5µm so also known as PM2.5
 usually contain secondarily formed
aerosols, combustion particles and organic
and metal vapours.
 Note:
number of PM= 1
mass of that particle in overall PM
i.e ultrafine particles contribute only a few
%to mass,while contribute 90% to the no.

12.  BECAUSE:
 these properties govern the transport and
removal of the particles from the air
 they govern their deposition within the
respiratory system
 They are associated with chemical
composition and sources of particles

13.  EFFECTS ON HUMAN HEALTH:
 Due to small size it is inhaled and damages
lungs of both children and adults

15.  PM can clog stomatal openings of plants and
interfere with photosynthesis functions
 High PM conc.in atmosphere can lead to
growth stunting and mortality in some plants
species.

16.  Particulated matter emissions are highly
regulated in most industrialized countries.
 Due to environmental concerns, Industries
are required to operate some kind of dust
collection system to control PM emissions.


17.  Following systems are used for controlling
PM emission
 1) INERTIAL COLLECTORS(CYCLONIC
COLLECTORS)
 2) FABRIC FILTER COLLECTORS(BAGHOUSES)
 3) WET SCRUBBERS
 4)ELECTROSTATIC PRECIPITATORS

18.  PRINCIPLE:
 centrifugal
Force(separation of
Particles on the basis of
Their sizes)
CONSTRUCTION:
 cylinder
 inlet
 dust outlet
 Clean gas outlet

19.  The feed is introduced tengentially at high
velocity and acquire an intense spinning
motion, moving downward in cylinder
chamber

20.  Because of high centrifugal
Force denser particles collide
With the chamber and begin to
Slide down to bottom outlet
 After reaching the conical base
the velocity
increases because of decrease
Area
 Low pressure area is created in
the middle of cyclone providing drag to stream
to move upward and exit through outlet
 Larger particles are collected at the bottom

21.  It is useful for removing larger coarse
particles and are often employed as a first
step or “pre cleaner” to other more efficient
collectors
 2)FABRIC FILTER COLLECTOR (BAGHOUSES)
Fabric filters are most commonly employed
in general industry

30.  Scrubbing solution(usually a mixture of water
and other compounds) is used.

36.  An electrostatic precipitator is a filteration
device that removes fine particles, like dust
and smoke , from a flowing gas using the
force of an induced electrostatic charge
minimally impeding the flow of gases through
the unit.

37.  It works on the principle of electrostatic
precipitation: