Air pollution may be described as contamination of the atmosphere by gaseous, liquid, solid wastes or by-products that can endanger life, attack materials and reduce visibility.

1
Introduction
2
Introduction

• Air pollution may be described as contamination
  of the atmosphere by gaseous, liquid, solid
  wastes or by-products that can endanger life,
  attack materials and reduce visibility.
• Air pollution worldwide is a threat to human
  health and the natural environment.
• It may also be defined as the presence of matter
  in atmosphere at concentrations, durations, and
  frequencies that adversely affect human health
  and environment.

3
Introduction

• Air pollution can be caused due to the burning of
  wood, coal, oil, petrol, or by spraying
  pesticides.
• Some of the questions which might come to  mind
  while thinking about air pollution are
• Are we doing something about solving these
  problems?
• Do we know enough about the conditions under
  which a pollution episode occurs?
• What are the regulations?
• How to control emissions?

4
Should we worry about Air Pollution?

• Air pollution affects every one of us.
• Air pollution can cause health problems and in an
  extreme case even death.
• Air pollution reduces crop yields and affects
  animal life.
• Air pollution can damage monuments.
• Air pollution can cause significant economic
  losses.
• In short, air pollution does not only damage air
  it also damages environment on earths surface
  and their inhabitants.

5
History of Air Pollution in the US

• The problems of air pollution in Los Angles, New
  York city, and Chicago during the fifties drew
  attention of regulators in the United States.
• Conventional pollutants due to auto emissions and
  smoke stacks were the major thrusts of air
  pollution during the sixties and seventies.
• Invisible emissions of toxic pollutants were
  recognized in the late seventies.
• In early eighties scientists observed a slow down
  in growth of red spruce in the mountain areas of
  north-eastern US as a result of acid rain.
• In early nineties standards for ozone air
  pollution and sulfur dioxide has been revised
• In late nineties standard for particulate matter
  pollution was strengthened.

6
History of Air Pollution in the US

• In 2000, EPA passed a new rule for diesel,
  capping sulfur levels in diesel fuel at 15 parts
  per million by 2007.
• In 2005, EPA issued the Clean Air Interstate Rule
  (CAIR), to achieve the largest reduction in SO2
  NOX from the atmosphere in the eastern United
  States.
• In 2006, EPA issued the strongest National Air
  Quality Standards for particle pollution in the
  countrys history.
• In 2010 (January 6th), EPA has proposed to
  strengthen the National Ambient Air Quality
  Standards for ground-level ozone.

7
Air Quality Standards Achievement
8
Accidents and Episodes

• 1930 -3 day fog in Meuse Valley, Belgium
• 1931 -9 day fog in Manchester, England
• 1948 -Plant emissions in Donora, Penn, US
• 1952 -4 day fog in London, England
• 1970 -Radionuclide emissions, Three Mile Island,
  US
• 1984 -Release of Methyl isocynate in Bhopal,
  India
• 1986 -Radionuclide releases, Chernobyl, Ukraine 
• 1997 Haze disaster in Indonesia
• 2001 Wildfires in Sierra Nevada, US
• 2001 Enormous clouds of dust in New York
  during Collapse of World Trade Center, US
• 2002 Violent dust storm in Queensland,
  Australia
• 2005 - Jilin chemical plant explosions, Jilin
  city, China
• 2007 Wildfires in TALLAHASSEE Florida, US
• 2008 - Kingston Fossil Plant coal fly ash slurry
  spill, Kingston, US

9
Eras of Air Pollution
Pre-Industrial Era
Early-Industrial Era
Early 20th Century
Late 20th Century
Early 21st Century
10
Air Pollutant

• Contaminant that affects human life, plant life,
  animal life and property could be termed as an
  air pollutant.
• Air pollutants are classified into two categories

Primary pollutants These pollutants are emitted
from a source directly into the atmosphere.
e.g. Sulfur dioxide and Hydrocarbons
Secondary pollutants These are formed due to
the chemical reaction among two or more
pollutants. e.g. Peroxyacetyl nitrate (PAN )
11
How to Define an Air Pollutant?

• Basis Chemicals present in the environment
• Process
• Use composition of the clean air as a bench mark.
  
• When the concentration of a chemical in air is
  above the bench mark, it is termed as an air
  pollutant .

12
Chemical Composition of Dry Air
13
Common Air Pollutants
The air pollution problem is encountered in both
indoor as well as outdoor.

• ? Outdoor
•   SO2
•   CO, CO2 
•   Oxides of Nitrogen
•   Ozone
•   Total Suspended particles
• Lead
• Particulates
• Volatile organic compounds
• Toxic Air pollutants

• ?  Indoor
• Radon
• Combustion by-products
• CO, CO2, SO2, Hydrocarbons, NOx
• Particulates, Polyaromatic hydrocarbons
• Environmental Tobacco Smoke (ETS)
• Volatile organic compounds
• Asbestos
• Formaldehyde
• Biological contaminants
• Pesticides

14
Sources of Air Pollutants

• Indoor

• Outdoor

15
Physical Forms of an Air Pollutant

• Gaseous form
•   Sulfur dioxide
•   Ozone
•   Hydro-carbon vapors 
• Particulate form
•   Smoke
•   Dust
•   Fly ash
•   Mists

16
Toxic Air Pollutants

• Toxic air pollutants may originate from natural
  sources as well as  from manmade sources such as
  stationary and mobile sources.
• The stationary sources like factories and
  refineries serve as major contributors to air
  pollution.
• The Clean Air Act of 1990 provides a list of 189
  chemicals to be regulated under the hazardous air
  pollutant provisions of the act.
• The list of hazardous air pollutants can be found
  in the EPA website.
• (http//www.epa.gov/ttn/atw/188polls.html)

17
Sources of Toxic Air Pollutants
18
Toxic Air Pollutants

• The toxic air pollutants released from industrial
  facilities, in the United States, are reported to
  the public via the Toxic Release Inventory (TRI)
• USEPA
• Major sources are defined as sources that emit
  10 tons per year of any of the listed toxic air
  pollutants, or 25 tons per year of a mixture of
  air.
• Area sources are defined as sources that emit
  less than 10 tons per year of a single air toxic,
  or less than 25 tons per year of a mixture of air
  toxics.

19
Units for measurement of Air Pollution

•    There are two units of measurement. They are
  as follows
•    µg/m3 and ppm (parts per million)
• At 25C and 1 atm
• At 00 C and at a pressure of 76 cm of Hg, volume
  of the air is 22.41 l/mol.
• To obtain volume at any temperature, use gas law
• P1V1/T1 P2V2/T2

20
Sources of Air Pollution

• Natural Sources
• Volcanoes
• Coniferous forests
•   Forest fires
•   Pollens
•   Spores
•   Dust storms
•   Hot springs
• Man-made Sources
•   Fuel combustion - Largest contributor
•   Chemical plants
•   Motor vehicles
•   Power and heat generators
•   Waste disposal sites
•   Operation of internal-combustion engines

21
Natural Sources vs. Man-made Sources

• Pollutants released from natural sources like
  volcanoes, coniferous forests, and hot springs
  have a minimal effect on environment when
  compared to that caused by emissions from
  man-made sources like industrial sources, power
  and heat generation, waste disposal, and the
  operation of internal combustion engines.
• Fuel combustion is the largest contributor to air
  pollutant emissions, caused by man, with
  stationary and mobile sources equally
  responsible.

22
Source Classification

• Sources may be classified as
• (A) Primary
•       Secondary
• (B) Combustion
•       Non-combustion
• (C) Stationary
•        Mobile
• (D) Point These sources include facilities that
  emit sufficient amounts of pollutants worth
  listing
•        Area all other point sources that
  individually emit a small
•        amount of pollutants are considered as
  area sources.

23
Source Classification
(E) Classification for reporting air emissions to
the public

• Transportation sources Includes emissions from
  transportation sources during the combustion
  process
•  Stationary combustion sources These sources
  produce only energy and the emission is a result
  of fuel combustion
•  Industrial sources These sources emit
  pollutants during the manufacturing of products
•  Solid waste Disposal Includes facilities that
  dispose off unwanted trash
•  Miscellaneous sources that do no fit in any of
  the above categories like forest fires, coal
  mining etc.

24
Problems
25
Exercise

• The exhaust from a 2001 Honda contains 2.5 by
  volume of carbon monoxide. Compute the
  concentration of CO in milligrams/m3 at 25C and
  1 atm of pressure.

26
Exercise

• Problem The exhaust from a 2001 Honda contains
  2.5 by volume of carbon monoxide. Compute the
  concentration of CO in milligrams/m3 at 25C and
  1 atm of pressure.
• Solution
• Step 1
• 1 percent by volume 104 ppm.
• 2.5 percent by volume 2.5104 ppm.
• Molecular Weight of CO is 28 g/mol
• Step 2
• 2.8 x 107 mg/m3 

27
Exercise

• Determine the actual volumetric flow rate in
  acfm assuming that pressure is constant, when the
  actual temperature is 400 F. The standard
  conditions are 70 F and 2000 cfm.

28
Exercise

• Problem
• Determine the actual volumetric flow rate in
  acfm assuming that pressure is constant, when the
  actual temperature is 400 F. The standard
  conditions are 70 F and 2000 cfm.
• Solution
• Step 1 Temperaturestd 70 F   530 R.
  Temperatureact 400 F 860 R.
• Step 2 qact qstd(Tempact / Tempstd).         
  
• 2000(860 / 530).         
• 3245.28 acfm

29
Exercise

• Calculate the density of a gas whose molecular
  weight is 29 at 1 atm, absolute and 50F.

30
Exercise

• Problem
• Calculate the density of a gas whose molecular
  weight is 29 at 1 atm, absolute and 50F.
• Solution
• Step 1 80 F     50 460 510 R
• R 0.73 atm-ft3 /lb mol-R.
• Step 2
• density P mol.wt/RT  
• density (129)/(0.73510)
•   0.0779 lb/ft3.