Introduction

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 earth’s 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 country’s 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. →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 →Outdoor •   SO2 •   CO, CO2  •   Oxides of Nitrogen •   Ozone •   Total Suspended particles • Lead • Particulates • Volatile organic compounds • Toxic Air pollutants

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 25°C 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 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. (E) Classification for reporting air emissions to the public:

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 25°C 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 25°C and 1 atm of pressure. Solution : Step 1 1 percent by volume = 104ppm. 2.5 percent by volume = 2.5*104ppm. 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 1Temperaturestd = 70 F   = 530 R. Temperatureact = 400 F = 860 R. Step 2qact = 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 50°F.

30. Exercise Problem : Calculate the density of a gas whose molecular weight is 29 at 1 atm, absolute and 50°F. Solution : Step 180 F     = 50 + 460 = 510 R R = 0.73 atm-ft3 /lb mol-R. Step 2 density = P * mol.wt/RT   density = (1*29)/(0.73*510) =  0.0779 lb/ft3.