Air pollutantion and control

1. AIR POLLUTION AND CONTROL TECHNOLOGY
(MES 202)

2. Detailed Syllabus:
Unit 1
Introduction, definition of air pollutant, general nature of air pollution problem, effects of major
pollutants on human, vegetation and other materials, global air pollution impact e.g. global warming,
depletion of ozone layer, acid rain etc. Weather and climate role in air pollutant mechanism.
Unit 2
Meteorology, lapse rate, stability conditions, wind velocity profile, stack plumes, plume rise,
calculation of plume rise, effective stack height Air quality monitoring; sampling duration, selection of
sampling sites, principle of sampling instruments, measurement units, sampling and analysis of SPM,
RSPM, SOx, NOx, and CO.
Unit 3
Dispersion of pollutant in the atmosphere, factors affecting the desperation phenomena, eddy diffusion
model, Gaussian dispersion equation, reduction of Gaussian dispersion equation to ground level C/L
concentration and for line sources, assumptions and limitations
Unit-4
Introduction, gaseous pollutants control devices and their working principle, absorption, adsorption,
combustion and condensation, SOx control and NOx control, process control, in combustion process
and treatment of flue gases, catalytic converters.
Unit 5
Introduction, particulate control equipments; gravity settling chambers, cyclone separators, fabric
filters, electrostatic precipitators and wet scrubber, working principle, design, advantage, and
disadvantages and limitations of equipments. Design of ventilation system, basics of hood and duct
design.
Gate syllabus and Net Syllabus: whatever you are going to add
You can also add using track change in word file

3. Suggested Books :
Air Pollution and Control, Crawford, McGraw Hill Series
Environmental Engineering, Peavy and Rowe, McGraw Hill Series
Air Pollution, Neol De Nevers, Tata McGraw Hill Pvt. Ltd. New Delhi India
Fundamentals of Air Pollution (Fourth Edition), Daniel A. Vallero
Introduction to Environmental Engineering, Masters & Masters, Printice Hall

4. DEFINITION
occurs when the air contains gases, dust, fumes or odor in harmful amounts.
 it is when concentrated gases exceed safe limits
Air Pollution can be defined as: The introduction of any chemical, physical or
biological agent into an atmosphere that has the potential to cause adverse impacts.
TYPES OF AIR POLLUTION
All types of air pollution can be divided into two basic types
Primary Air Pollutants are emitted directly into the atmosphere. For example,
carbon monoxide is emitted by cars and light-duty trucks.
Secondary Air Pollutants are formed within the atmosphere by chemical
reactions involving precursors that are emitted into the atmosphere. Ozone a
primary component of “smog” is formed by sunlight-driven reactions involving
volatile organic compounds (VOC) and nitrogen oxide precursors.
Outdoor Air Pollution
o Smog
o Particulates
o Acid Rain
o Greenhouse Gases
Indoor Air Pollution

5. For regulatory purposes
The U.S. Clean Air Act, its amendments and subsequent litigation separates air pollutants
into three categories
Criteria Pollutants are common pollutants that were known to produce adverse health
effects at the passage of the Clean Air Act Amendments (CAAA) of 1970.
These include: ozone, particulate matter, sulfur dioxide, carbon monoxide, nitrogen
dioxide, and lead. EPA was required to develop and update National Ambient Air
Quality Standards (NAAQS) for each of these compounds.
Hazardous Air Pollutants or air toxics are compounds proven, or expected to be,
carcinogenic, mutagenic, teratogenic or capable of producing other adverse health or
environmental effects. The CAAA of 1990 specified 187 air toxics for regulation.
Greenhouse Gases or Radiatively Important Trace Substances (RITS)

6. CAUSES
Natural Sources
e.g. smoke that comes from wildfires, volcanoes, methane, dust
Human Sources
 e.g. power plants and automobiles, fumes, burning wood stoves, fireplaces, and furnaces
Pollutants
Carbon Dioxide
Carbon Monoxide
 Sulfur Dioxide
Nitrogen Dioxide

8. Primary Mechanism
Formation of VOC
Biological generation of VOC
Formation of liquid aerosol droplets
Anthropomorphic generation of particulate aerosol
Biological formation of particulate aerosols
Particulate aerosol formation

9. Secondary Mechanism
 Condensation
 Adsorption
 Nucleation

10. How are These Agents Introduced into
the Atmosphere?
• There are four types of sources that emit air pollutants
– Stationary Sources
– Mobile Sources
– Area Sources
– Natural Sources
• There are four primary ways in which pollutants can be emitted into the
atmosphere
– Combustion and Thermal Processes
– Evaporation
– Physical (Mechanical) Processes
– Biological (Metabolic) Processes

11. What is Particulate Matter?
Particulate matter (PM)
describes a wide variety of
airborne material. PM pollution
consists of materials (including
dust, smoke, and soot), that are
directly emitted into the air or
result from the transformation of
gaseous pollutants. Particles come
from natural sources (e.g., volcanic
eruptions) and human activities
such as burning fossil fuels,
incinerating wastes, and smelting
metals.
Image from http://www.epa.gov/eogapti1/
module3/distribu/distribu.htm

12. How is PM Regulated?
PM is one of the six EPA “criteria pollutants” that have been
determined to be harmful to public health and the environment. (The
other five are ozone, sulfur dioxide, nitrogen dioxide, carbon
monoxide, and lead.)
EPA is required under the Clean Air Act to set national ambient air
quality standards (NAAQS) to protect public health from exposure
to these pollutants. Areas that exceed the NAAQS are designated as
nonattainment, and must institute air pollution control programs to
reduce air pollution to levels that meet the NAAQS.

13. PM
Where Does PM Originate?
VOCs
NO2
SO2
Sources may emit PM directly into the environment or emit precursors such as
sulfur dioxide (SO2), nitrogen dioxide (NO2), and volatile organic
compounds (VOCs), which are transformed through atmospheric chemistry to
form PM.
Ammonia (NH3)
Ammonia (NH3)

14. Sources of PM and PM Precursors
Mobile Sources
(vehicles)
VOCs, NO2, PM
Stationary Sources
(power plants, factories)
NO2, SO2, PM
Area Sources
(drycleaners, gas stations)
VOCs
Natural Sources
(forest fires, volcanoes)
PM

15. Determinants of PM Concentration
• Weather patterns
• Wind
• Stability (vertical movement of air)
• Turbulence
• Precipitation
• Topography
• Smoke stack height and temperature of gases
Nearby natural and built structures may lead to downward moving
currents causing aerodynamic or building downwash of smokestack
emissions.

16. • Air pollution is a multi-step process
– Compounds are emitted into the atmosphere by both man-made and
natural sources (emissions sources)
– The compounds are mixed, dispersed and transported by
meteorological conditions (transport phenomena)
– As these components are being mixed and transported, they are
undergoing chemical reactions that can remove, transform or
produce new compounds (atmospheric chemistry)
– At some point this parcel of air will reach an individual who,
through normal respiration, will bring a portion of this parcel into
his/her lungs where the compounds will have an opportunity to
interact with the lung tissues before being exhaled (respiration)
– These compounds can have an influence on the individual (health
effects)
General Discussion