1. Introduction
Air pollution worldwide is a growing threat to human health and the natural environment
Air pollution may be described as contamination of the atmosphere by gaseous, liquid, or solid wastes or by-products that can endanger life, attack materials and reduce visibility
Some of the questions which might come to mind while thinking about 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?

2. Sources Of Air Pollutants
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

3. Ambient Air
The air all around us

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 soil and corrode materials, and monuments
Air pollution can cause significant economic losses

5. Accidents and Episodes
1930 -3 day fog in Meuse Valley, Belgium
day fog in Manchester, England
1948 -Plant emissions in Donora, Penn, USA
1952 -4 day fog in London
1970 -Radionuclide emissions, Three Mile Island, USA
1984 -Release of Methyl isocynate in Bhopal, India  
1986 -Radionuclide releases, Chernobyl, Ukraine 

6. Air Quality Indoor Radon Combustion by-products
CO, CO2, SO2, Formaldehyde, Hydrocarbons, NOx,
Particulates, Polyaromatic hydrocarbons
Environmental Tobacco Smoke (ETS)
Volatile organic compounds
Formaldehyde
Biological contaminants
Pesticides
Outdoor
SO2
CO, CO2
NO2
Ozone
TSP Pb
Toxic pollutants

7. Definition of an Air Pollutant
A contaminant that affects human life, plant life, animal life and property or a contaminant which interferes with the enjoyment of life and property is an air pollutant
Ohio EPA provides a definition of "Air pollutant" or"air contaminant “as particulate matter, dust, fumes, gas, mist, smoke, vapor, or odorous substances.

8. How to define an air pollutant ?
Basis: Chemicals present in the environment
Process:
Use composition of the clean air used as a bench mark.
When the concentration of a chemical is above the concentration of the chemical present in air, it is termed as an air pollutant

9. Physical Forms of Air Pollutants
Gaseous form
Sulfur dioxide
Ozone
Hydro-carbon vapors
Particulate form
Smoke
Dust
Fly ash
Mists

10. Classification of Pollutants
Primary pollutants: remain in the same chemical form, as they are released from a source directly into the atmosphere.
Sulfur dioxide
Hydrocarbons
Secondary pollutants: are a result of chemical reaction among two or more pollutants.
PAN

11. Common Air Pollutants Sulfur Dioxide Hydrocarbons Ozone
Total Suspended Particulate Matter/Fine Particulates
Nitrogen Oxides
Carbon Monoxide
Lead
Carbon Dioxide

12. 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
(See EPA site for current list chemicals)

13. 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
Natural (biogenic)

14. 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 c categories like forest fires, coal mining etc.

15. Air Pollution Index
Air pollution indices were introduced to translate technical information on concentration levels of various pollutants into a simple and easy to understand language for the public
The U.S.E.P.A has developed the pollutant standard index (PSI) for introducing consistency in providing information regarding the air quality throughout the U.S. The system is based on a scale of 0-500
Index Value is assigned based on the amount of air pollutants in the air and associated health effect

16. Development of an Emission Inventory
Emission Inventory is a study of the pollutant emissions from sources in a given area
Emission Inventories have been developed by:
plant
local environmental agency
national environmental agency
Details for development of an emission inventory depend on:
area of coverage
nature of sources
purpose
Well known emission inventories in US
Inventory of criteria pollutants
Toxic release inventory (TRI)

17. Steps to Develop Emission Inventory
Steps Involved in development of an emission inventory are:
Planning
Data Collection
Data Analysis
Reporting Data

18. Planning Defines scope and purpose of inventory
Major points considered during this step are:
Pollutants to be enlisted in the inventory are specified along with the methods to collect or estimate data
Use of data and geographical area involved are determined
Legal authority and responsibility of specific groups to acquire data is considered along with an assessment of cost and resources

19. Data Collection Steps to be taken: Emissions are classified
Pollutant sources are located and classified
Quality and quantity of materials handled, processed, or burned is determined
Collection Methods: During this stage data may be collected by
Mail survey
Plant inspection
Field surveys
Data from literature:
Industrial files
Government files
Periodicals
Trade journals
Scientific publications

20. Information Collected during Data Collection
General source information - location, ownership, and nature of business
Activity levels - amount of fuel and materials (input)
Amount of production - output of the plant
Control device information - type of pollution control devices
Information required to estimate emissions - temperature, tank conditions, hours of operations, seasonal variation and other data

21. Data Analysis Check accuracy
Calculation of emission rate is done using:
Monitoring data (most accurate & most expensive)
Emission factors from AP-42 ,
Mass balance, and
Engineering calculation

22. Emission Rate
Emission rate is the weight of a pollutant emitted per unit time.
Emission factor is an estimate of the rate at which a pollutant is released into the atmosphere per unit level of activity
To calculate emission rate: EMISSION RATE = [INPUT] x [EMISSION FACTOR] x [APLICABLE CORRECTION FACTORS] x [HOURS OF OPERATION] x [SEASONAL VARIATION]

23. Reporting Data
Information can be filed with the following pollution control agencies:
Local
Regional
National
In US, data gathered by state agencies are reported to the USEPA
Emission data are available from the USEPA’s web site

24. Uses of an Emission Inventory
The Emission Inventory developed may be used for:
Identifying types of pollutants emitted from specific sources.
Determining the magnitude or amount of emissions from those sources
Developing the emissions distribution in time and space
Calculating emission rates under specific plant operating conditions
Finding out the relation of ambient air pollutant concentration with specific sources
Input data for air quality modeling and risk
Determine pollution control options for public health
Estimating cost based on emissions

25. Air Pollution in Asia
Asia represents a major source of air pollution as a result of rapid population growth, explosive industrialization, and few environmental regulations
China:
China is polluted with sulfur dioxide (15 million tons) and particulate matter (20 million tons) because of the use of the high sulfur coal used to generate energy.  
Other Chemicals:
1. Carbon Dioxide from Industry
2. Greenhouse Gases from Industry
3. Nitrogen Oxides from Cars
4. Acid Rain
With all these problems China has very little air pollution control.

26. Air Pollution in Asia India:
Most common air pollutant: suspended particulate matter is due to use of coal in power plants
Use of low quality coal produces 45 million metric tons of ash annually
When particulate matter ash is mixed with auto exhaust the emissions across limits resulting in an increase in respiratory diseases and allergies
South Korea:
SO2 is the major pollutant in South Korea, however, it is being controlled by using air pollution control equipment
Hong Kong:
Vehicular emissions contribute to air pollution problems with diesel powered engines being the prime culprit.

27. ppm and µg/m3 relationship
Convert From To
Multiply by
micrograms/m3
PPM (vol) /M
PPM (wt) M/
where M is the molecular weight of the pollutant gas.