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?

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

Ambient Air

The air all around us

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

Accidents and Episodes

1930 -3 day fog in Meuse Valley, Belgium 1931 -9 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 

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

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.

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

Physical Forms of Air Pollutants

Gaseous form Sulfur dioxide Ozone Hydro-carbon vapors

Particulate form Smoke Dust Fly ash Mists

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

Common Air Pollutants

Sulfur Dioxide Hydrocarbons Ozone Total Suspended Particulate Matter/Fine Particulates Nitrogen Oxides Carbon Monoxide Lead Carbon Dioxide

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)

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)

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.

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

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)

Steps to Develop Emission Inventory

Steps Involved in development of an emission inventory are:

Planning

Data Collection

Data Analysis

Reporting Data

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

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

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

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

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]

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

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

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.

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.

ppm and µg/m3 relationship

Convert From To Multiply bymicrograms/m3 PPM (vol) 0.02404/M

micrograms/m3 PPM (wt) 0.000835

PPM (vol) micrograms/m3 M/0.02404

PPM (wt) micrograms/m3 0.001198

where M is the molecular weight of the pollutant gas.