1. Air Pollution Episode
period of abnormally high concentration of air pollutants, often due to low winds and temperature inversion, that can cause illness and death

2. Common Air Pollutants → Outdoor → Indoor SO2 Radon CO, CO2
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
Biological contaminants
Pesticides
→ Outdoor
  SO2
  CO, CO2 
  Oxides of Nitrogen
  Ozone
  Total Suspended particles
Lead
Particulates
Volatile organic compounds
Toxic Air pollutants

3. Sources of Air Pollutants
Indoor
Outdoor

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

5. 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.

6. Sources of Toxic Air Pollutants

7. Toxic Air Pollutants
EPA
“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.

8. Sources of Air Pollution
Natural Sources
Volcanoes
Coniferous forests
  Forest fires
  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

9. 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.

10. 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.

11. 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.

12. Air Quality Measurements

13. The exhaust from a 1981 Honda contains 1
The exhaust from a 1981 Honda contains 1.5% by volume of carbon monoxide. Compute the concentration of CO in milligrams/m3 at 25°C and 1 atm of pressure. Solution

14. UNITS OF MEASUREMENT
There are 3 basic units used in reporting air pollution data that are micrograms per cubic meter (µg/m3), parts per million (ppm) and the micron (µ) or preferably known as micrometer (µm).
Micrograms per cubic meter and parts per million are unit of measurement for concentration and they are used to indicate the concentration of gaseous pollutant.
The µm is used to report the particle size.
Formerly concentration of gaseous pollutants were usually reported in parts per million (ppm), parts per hundred million (pphm), or parts per billion (ppb) by volume.
Thus, designations in µg/m3 may be followed by equivalent concentration on a ppm basis - e.g. 80 µg/m3 (0.03 ppm) of sulfur dioxide.

15. µg/m3 = ppmx 10-6 xGMW x103 L/m3 x106 µg/g L/mol
For gases, ppm can be converted to µg/m3 by using the following formula:
µg/m3 = ppmx 10-6 xGMW x103 L/m3 x106 µg/g
L/mol
GMW = gram molecular weight of gas
‘L/mol’ term is influenced by the temperature (T) and pressure (P) of the gas. According to Avogadro’s Law, 1 mole of any gas occupies the same volume as 1 mole of any gas at the same T and P.
Therefore, at 273 K (0OC) and 1 atm pressure (760 mmHg /101.3 kPa), standard conditions for many chemical reactions, the volume is 22.4 L/mol.

16. To convert to L/mol at other conditions, the following formula can be used:
V1P1 = V2P2
T T2
where V1, P1 and T1 is relate to the standard condition V2, P2 and T2 is relate to the actual condition that is being considered.

17. EXAMPLE :
Calculate the volume occupied by 4 mol of gas at 21.1OC and 760 mmHg.
SOLUTION:

18. EXAMPLE :
The NO2 content of a sample of stack gas measured at 950OC at 2 atm pressure was 9 ppm. Determine the NO2 concentration in µg/m3 and mg/m3. NO2 weight 46 g/mol.
SOLUTION:

19. EXAMPLE :
What volume would one mole of an ideal gas occupy at 25.00C and kPa?.
SOLUTION:

20. Determine the volume of 6 mol of gas at 370C and 700 mmHg.
EXAMPLE :
Determine the volume of 6 mol of gas at 370C and 700 mmHg.
SOLUTION:

21. Convert 7.5 ppm of 64 g/mol SO2 to µg/m3 at 80OC and 110.5 kPa.
EXAMPLE :
Convert 7.5 ppm of 64 g/mol SO2 to µg/m3 at 80OC and kPa.
SOLUTION:

22. Air Quality Index (AQI)
AQI helps in understanding the level at which air is polluted and the associated health effects that might concern.
EPA calculates the AQI for five major air pollutants : ground-level ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide.
For each of these pollutants, EPA has established national air quality standards to protect public health.
The EPA has developed the pollutant standard index (PSI) for introducing consistency in providing information regarding the air quality throughout the US.

23. (AQI)
Good: The AQI value for a community is between 0 and 50 then the air quality is considered satisfactory, and air pollution poses little or no risk. Moderate: The AQI is between 51 and 100 then the Air quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of people. Unhealthy for Sensitive Groups: When AQI values are between 101 and 150, members of sensitive groups may experience health effects. This means they are likely to be affected at lower levels than the general public.

24. Unhealthy: Everyone may begin to experience health effects when AQI values are between 151 and 200. Members of sensitive groups may experience more serious health effects. Very Unhealthy: AQI values between 201 and 300 trigger a health alert, meaning everyone may experience more serious health effects. Hazardous: AQI values over 300 trigger health warnings of emergency conditions. The entire population is more likely to be affected.

25. Air Quality Standards
Clean Air Act has developed National Ambient Air Quality Standards to protect public health and environmental resources.
The air quality standards are classified into two types.
Primary standards: Protect public health, including the health of "sensitive" populations such as asthmatics, children, and the elderly.
Secondary standards: Protect public welfare, including protection against decreased visibility, damage to animals, crops, vegetation, and buildings.

26. National Ambient Air Quality Standards

27. Air Quality Regions
Any region within a state is designated as either attainment or nonattainment area.
Attainment area is the region where the air quality is within the national ambient air quality standards.
Nonattainment area is the region where the air quality exceed national ambient air quality standards.
An area may fall into both categories for different pollutants.
Permits are issued to the sources considering the amount of pollutants that are expected to emit per year.

28. 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 [APPLICABLE CORRECTION FACTORS] x [HOURS OF OPERATION] x [SEASONAL VARIATION]