Prof. Rajesh Bhagat Asst. Professor Civil Engg. Department Y. C. C. E., Nagpur

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1 Prof. Rajesh Bhagat Asst. Professor Civil Engg. Department Y. C. C. E., Nagpur Mobile No.: / ID:- rajeysh7bhagat@gmail.com Website:- B. E. (Civil Engg.) M. Tech. (Environmental Engg.) GCOE, Amravati VNIT, Nagpur 1) GATE Exam Qualified Two Times. 2) Junior Engineer, Z. P. Washim. 3) Lecturer, K.D.K. College of Engineering, Nagpur 4) Lecturer, P. R. Pote (Patil) College of Engg., Amravati. 5) Assistant Professor, P.C.E., Nagpur. 6) Assistant Professor, Cummins College of Engg. For Women, Nagpur. 7) Scientist, Council of Scientific & Industrial Research, India.

2 UNIT-I 1. Introduction to Air Pollution. 2. Classification and Sources of Air Pollutants. 3. Effects of Air Pollutants on Man, Plants, Animal & Materials. 4. Atmosphere and Its Zones. 5. Air Pollution Episodes.

3 UNIT-II 1. Meteorological parameters: Primary & secondary. 2. Atmospheric stability & plume behavior. 3. Air sampling and measurement.

4 UNIT-III 1. Air Pollution Control: Industrial Air Pollution Controlling Devices, Gravity Settling Chamber, Cyclone & Fabric Filter, Wet Scrubber & Electrostatic Precipitator. 2. Gaseous Air Pollution Controlling Devices: Absorption, Adsorption & Oxidation. 3. Automobile Exhaust. 4. Noise Pollution, Its Effects & Control.

5 Atmosphere:- Insulating blanket protecting the earth. Softens the intense light & heat of the sun. Ozone layers acts as protecting umbrella that absorbs dangerous UV rays. Atmosphere is bound to the earth by gravity. As we go higher & higher, the characteristics & composition changes. Atmosphere is divided into four sphere. 1. Troposphere 2. Stratosphere 3. Mesosphere 4. Thermosphere or Ionosphere 5

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7 Atmospheric Layers:- Atmosphere is divided into four sphere:- 1. Troposphere 2. Stratosphere 3. Mesosphere 4. Thermosphere or Ionosphere 7

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9 Troposphere:- Lowest gaseous layer of the atmosphere. Region of weather & clouds. Extends to a height of about 10 km from the earth. Contains nearly 2/3 rd of total mass of the atmosphere. Temperature drops with increase in altitude (6 OR 6.5 C /km- Wet & 10 C /km - Dry)

10 Stratosphere:- 2 nd layer of atmosphere above troposphere starting from 20km to 50km (30 km thick) Free from violent weather changes so preferred by jet liners. Temp. increase with altitude due to presence of ozone layer. Layers of ozone is not uniform in thickness.(highest at equator & lowest at Poles) Boundary that divides stratosphere from mesosphere is called the stratopause.

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13 Mesosphere:- Region where few energy release reaction occur. Lapse rate is +ve (decrease in temp.) Coldest layer of atmosphere. This layer has no significance in air pollution.

14 Ionosphere:- Thermosphere Very high temp c over equator c over north pole. Highest & vastest zone of atmosphere. Starting at 115km above the earth upto 600km. Region beyond 600km is termed as exosphere. 14

15 Atmospheric stability:- The resistance of the atmosphere to vertical motion or mixing. Lapse rate :- (vertical temp. gradient) Rate at which temp. changes with elevation is called lapse rate. Lapse rate in a Dry Adiabatic Atmosphere is called DALR (10 0 C/km) & (WALR 6 0 C/km). Actual lapse rate is called Environmental Lapse Rate ie ELR may be greater or less than the DALR. ELR determines whether the air or atmosphere is stable or unstable. If the air is unstable, the vertical movement of air is encouraged, & If the air is stable, vertical movement of air is discouraged. Super Adiabatic Lapse rate = Rate is more than DALR. Inversion = -ve lapse rate. 15

16 Stability of atmosphere depending upon the vertical air temperature distribution :- Very stable : Temperature increases with increase in altitude. This is a -ve lapse rate, or an Inversion. Stable : Environmental lapse rate is less than the dry adiabatic lapse rate, but temperature decreases with altitude increase. Neutral : Environmental lapse rate is the same as the dry adiabatic lapse rate. Unstable : Environmental lapse rate is greater than the dry adiabatic lapse rate. Very unstable : Environmental lapse rate is much greater than the dry adiabatic rate, and is called super-adiabatic. 16

17 Stability is the degree to which the atmosphere will support, tolerate, or suppress vertical motions. In a stable atmosphere, a parcel of air that is displaced upwards will tend to return to its original level while in an unstable atmosphere, a parcel of air displaced upwards will continue to rise. DTEL Fig. 6.9 Lapse Rate (16) 17

18 Fig Lapse Rate (16)

19 WALR ELR WALR DALR DALR ELR ELR WALR DALR 19

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21 Lapse Rate Example Que.1:- Assuming the surface temperature is 15 C at the surface of the earth, what is the temperature at m? Take ELR = 6.49 C/km

22 Lapse Rate Example Que.1:- Assuming the surface temperature is 15 C at the surface of the earth, what is the temperature at m? Take ELR = 6.49 C/km Solution: m = km For each km the temperature decreases by 6.49 c So the temperature decreases: x 6.49 = c Original temp was 15, temp at km = 15 c c = C

23 Plume refers to the path & extents of the air pollutants released from stack source into the atmosphere. Depends on the vertical temp. & wind profile. Plume Behavior are of six types : 1) Looping plumes 2) Coning plumes 3) Fanning plumes 4) Lofting plumes 5) Fumigation plumes 6) Trapping plumes 23

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25 Fanning plumes form under very stable conditions. (extreme inversion condition) spread out horizontally but do not mix vertically. take place when the air temperature increases with altitude (inversion or ve lapse rate). The plume rarely reaches the grounds level unless the inversion is broken by surface heating or the plume encounters a hill. At night, with light winds and clear skies, fanning plumes are most probable. Fig Fanning Plumes (16) DTEL 25

26 Lofting plumes form when there is a stable layer beneath unstable layer. diffuse upward but not downwards and occur when there is a super-adiabatic layer above a surface inversion. generally not reach the ground surface. a flat bottom and a rising top. Fig Lofting Flumes (16) DTEL 26

27 Looping plumes take place when there has been a super-adiabatic lapse rate and solar heating. (Warm season) Wavy character occurs in a highly unstable atmosphere bcoz of rapid mixing. (Day Time) High turbulence disperse the plume rapidly but high conc. may occur close to the stack if plume touches the ground. Fig Looping Plumes (16) DTEL 27

28 Coning plumes Shaped like a cone roughly 10 0 with horizontal axis. Coning plume gets resulted in when the vertical air temperature gradient has been between dry adiabatic and isothermal, the air being slightly unstable with some horizontal and vertical mixing occurring. Coning is most likely to occur during cloudy or windy periods. Fig Coning Plumes (16) DTEL 28

29 Fumigation Plume causes the high pollutant concentration plume reaching the ground level along the length of the plume and is caused by a super-adiabatic lapse rate beneath an inversion. The super-adiabatic lapse rate at the ground level occurs due to the solar heating. This condition has been favored by clear skies and light winds. Usually start when a fanning plume breaks up into a looping plume. Fig Fumigating Plumes(16) DTEL 29

30 Trapping: In stable atmosphere both above & below stack with an unstable atmosphere in between two inversion layer. Diffuse only in the limited vertical height Occur at any time of the day in any season. 30

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33 Meteorology & Air Pollution: Meteorology is the study and forecasting of weather changes resulting from large scale atmospheric circulation Meteorological parameter can trigger an air pollution episodes. Once Pollutants Emitted:- Transported, Dispersed, Concentrated By meteorological conditions. Parameters can be classified into primary and secondary depending upon importance. 1. Wind Direction & Speed 2. Atmospheric Stability 3. Temperature 4. Mixing Height 5. Precipitation 6. Humidity 7. Solar Radiation 33

34 Wind Direction & Speed:- Govern the drift & diffusion of air pollutants discharged. Higher the wind speed at or near the point of discharge, the more rapidly will carry away from the source and will disperse dilute with greater volume of air. On the other hand, when wind speed are low pollutants tend to be concentrated near the area of discharge for longer periods. 34

35 Temperature & Heat:- Heat is the critical atmospheric variable. Comes from the sun as a short wave radiation. After striking the earth it losses energy & reradiates to the space as a long wave radiation. Some of radiation absorbed by the atmosphere & temp. increases. 35

36 Atmospheric Stability:- Ability to resists or enhance vertical motion. Rate at which temp. changes is called lapse rate. DALR = 10 O C/Km & WALR = 6.5 O C/Km (Neutral atmosphere) Reverse or -ve lapse means Inversion. During Inversion, vertical air movement is stopped & pollution will be concentrated beneath the inversion layer. 36

37 Mixing Height:- Height above the earth surface to which related pollutants will extend. Primarily through the action of atmospheric turbulence. Related to wind direction, wind speed & wind turbulence. 37

38 Precipitation:- Cleansing action on the air pollutants discharged onto the atmosphere. Removes the gaseous pollutants that are soluble in water. Act as scrubbing fluid for the removal of air pollutants. Thus it accelerates the deposition of pollutants on the ground.(water pollution & soil Pollution) 38

39 Humidity:- Measure of water vapour in atmosphere. Always present in atmosphere & depends on temp. Coastal regions & areas adjacent to huge water bodies are humid. Moisture content of the atmosphere influence the corrosive action of air pollutants. Also influence the potentiality for fog formation. Humidity act as catalyst in the reaction of air pollutants like SO 2, NO 2, etc. 39

40 Solar Radiation:- Depending on the location, solar radiation can have a pronounced effect on the type & rate of chemical reaction in the atmosphere. Photochemical smog formation at Los Angels is a typical example of the effect of solar radiation on air pollution. 40

41 Stack Height & Effective Stack Height:- Height of the stack and the height of rise of the plume above the stack play a major role in the ground level conc. expected on the down wind side. The plume Rise depends upon many factors such as exit velocity, wind speed, diameter of stack, temp. of plume, lapse rate, etc. 41

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44 H = h + Δh Where, H effective height if stack h Actual Height of stack Δh The Rise of Plume There are several formulae are available to calculate the stack height. As per Emission regulation published by the central board for prevention and control of pollution, New Delhi, The chimney height is to be calculated according to the formulae. PM :- H = 74 (Q) 0.27 Where, Q = Particulate Matter Emission in Tonnes per Hour. h = Height of Chimney in meters. Gaseous Pollutants :- H = 14 (Q) 0.3 Where, Q = Gaseous Emission in Kg per Hour. h = Height of Chimney in meters. 44

45 Que. 1: A factory uses 2,00,000 liters of furnace oil per month. If for one million liters of oil used per year, the particulate matter emitted is 3.0 tonnes per year, SO2 emitted is 59.7 tonness per year, NOx emitted is 7.5 tonnes per year, Hydrocarobns emitted are 0.37 tonnes per year and CO emitted is 0.52 tonnes per year, calculate the height of the chimney required to be provided for safe dispersion of the pollutants. Consumption of oil = 2,00,000 x 12 = 24,00,000 L/Year = 2.4 Million L/Year Particulate Emission per million Liters per Year = 3.0 Tonnes/Year Total Particulate Emission (Q) = 2.4 x 3.0 = 7.2 Tonnes/Year 45

46 Que. 1: A factory uses 2,00,000 liters of furnace oil per month. If for one million liters of oil used per year, the particulate matter emitted is 3.0 tonnes per year, SO2 emitted is 59.7 tonness per year, NOx emitted is 7.5 tonnes per year, Hydrocarobns emitted are 0.37 tonnes per year and CO emitted is 0.52 tonnes per year, calculate the height of the chimney required to be provided for safe dispersion of the pollutants. Consumption of oil = 2,00,000 x 12 = 24,00,000 L/Year = 2.4 Million L/Year Particulate Emission per million Liters per Year = 3.0 Tonnes/Year Total Particulate Emission (Q) = 2.4 x 3.0 = 7.2 Tonnes/Year SO2 Emission per million Liters per Year = 59.7 Tonnes/Year Total SO2 emission, Q = 2.4 x 59.7 = 144 Tonnes/Year = 20 Kg/Hr 46

47 Que. 1: A factory uses 2,00,000 liters of furnace oil per month. If for one million liters of oil used per year, the particulate matter emitted is 3.0 tonnes per year, SO2 emitted is 59.7 tonness per year, NOx emitted is 7.5 tonnes per year, Hydrocarobns emitted are 0.37 tonnes per year and CO emitted is 0.52 tonnes per year, calculate the height of the chimney required to be provided for safe dispersion of the pollutants. Consumption of oil = 2,00,000 x 12 = 24,00,000 L/Year = 2.4 Million L/Year Particulate Emission per million Liters per Year = 3.0 Tonnes/Year Total Particulate Emission (Q) = 2.4 x 3.0 = 7.2 Tonnes/Year PM :- h = 74 (Q) 0.27 Where, Q = Particulate Matter Emission in Tonnes per Hour. h = Height of Chimney in meters. 47

48 Assuming Working Days = 300 Days Assuming Working Hours per Day = 24 Hours Total Particulate Emission (Q) = ((7.2)/(300x 24)) = 0.001Tonnes/Hour PM :- h = 74 (Q) 0.27 h = 74 (0.001) 0.27 h = m 48

49 Gaseous Pollutants :- SO 2 :- h = 14 (Q) 0.3 Q = SO 2 Emission in kg/hr 49

50 SO 2 :- h = 14 (Q) 0.3 Q = SO 2 Emission in kg/hr Q = 2.4 x 59.7 = 144 Tonnes/Year = 20 Kg/Hr 50

51 SO 2 :- h = 14 (Q) 0.3 Q = SO 2 Emission in kg/hr Q = 2.4 x 59.7 = 144 Tonnes/Year = 20 Kg/Hr h = 14 (20) 0.3 h = 34.4 m Therefore adopt a height of 34.4 m (whichever is max.) 51

52 SO 2 :- h = 14 (Q) 0.3 Q = SO 2 Emission in kg/hr Q = 2.4 x 59.7 = 144 Tonnes/Year = 20 Kg/Hr h = 14 (20) 0.3 h = 34.4 m Therefore adopt a height of 34.4 m (whichever is max.) Note :- Since the emission of SO 2 is much more than that of NOx, CO 2, CO & Hydrocarbons, the calculation of stack height is done based on SO 2 emission data only 52

53 Effective Height of stack:- H = h + Δh Where, H effective height if stack h Actual Height of stack Δh The Rise of Plume Holland s equation :- Δh = ((v s x d)/u) ( x 10-3 x p x d ((Ts Ta)/Ts)) Where, p = Atmospheric pressure in millibars Ts = Stack temp. in O K Ta = Air Temp. in O K V s = Stack Gas Velocity d = Diameter of Stack in m u = wind Velocity in m/s 53

54 Que 2 :- Calculate the effective stack height for following data:- Physical Stack = 203 m tall with 1.07 m in side diameter Wind velocity = 3.56 m/s Air Temp = 13 O C Barometric Pressure = 1000 millibars Stack gas velocity = 9.14 m/s Stack gas temp. = 149 O C 54

55 Que 2 :- Calculate the effective stack height for following data:- Physical Stack = 203 m tall = h Side diameter = 1.07 m = d Wind velocity = 3.56 m/s = u Air Temp = 13 O C = Ta Barometric Pressure = 1000 millibars = p Stack gas velocity = 9.14 m/s = V s Stack gas temp. = 149 O C = Ts Temperature :- Ts = 149 O C = 422 O K Ta = 13 O C = 283 O K 55

56 Que 2 :- Calculate the effective stack height for following data:- Physical Stack = 203 m tall = h Side diameter = 1.07 m = d Wind velocity = 3.56 m/s = u Air Temp = 13 O C = Ta Barometric Pressure = 1000 millibars = ρ Stack gas velocity = 9.14 m/s = V s Stack gas temp. = 149 O C = Ts Temperature :- Ts = = 422 O K Ta = 13 O C = 283 O K Holland s Equation :- Δh = ((v s x d)/u) ( x 10-3 x p x d ((Ts Ta)/Ts)) 56

57 Que 2 :- Calculate the effective stack height for following data:- Physical Stack = 203 m tall = h Side diameter = 1.07 m = d Wind velocity = 3.56 m/s = u Air Temp = 13 O C = Ta Barometric Pressure = 1000 millibars = ρ Stack gas velocity = 9.14 m/s = V s Stack gas temp. = 149 O C = Ts Temperature :- Ts = = 422 O K Ta = 13 O C = 283 O K Holland s Equation :- Δh = ((v s x d)/u) ( x 10-3 x p x d ((Ts Ta)/Ts)) Δh = ((9.14 x 1.07)/3.56) ( x 10-3 x 1000 x 1.07 (( )/422s)) Δh = 5.92 m 57

58 Que 2 :- Calculate the effective stack height for following data:- Physical Stack = 203 m tall = h Side diameter = 1.07 m = d Wind velocity = 3.56 m/s = u Air Temp = 13 O C = Ta Barometric Pressure = 1000 millibars = ρ Stack gas velocity = 9.14 m/s = V s Stack gas temp. = 149 O C = Ts Temperature :- Ts = = 422 O K Ta = 13 O C = 283 O K Holland s Equation :- Δh = ((v s x d)/u) ( x 10-3 x ρ d ((Ts Ta)/Ts)) Δh = ((9.14 x 1.07)/3.56) ( x 10-3 x 1000 x 1.07 (( )/422s)) Δh = 5.92 m (Rise of Plume ) H = h + Δh = = m (Effective Height of stack) 58

59 Air Pollution Indices or Index (API) 1) It is system in which one can explain the quality of air to common man. 2) It is a scheme that transforms values of individual air pollution parameters into a single number. 3) Technical terms may not be known to public. 4) There must be easiest, understanding & simplified way to define quality of ambient air. 5) Criteria for Index:- 1) Easily understand by public 2) Include major air pollutants 3) Calculated in simpler manner 4) Based on scientific data 5) Meaningful 6) Relate to ambient air quality standards & goals 7) Can be forecasted a day in advance 59

60 Air Pollution Indices or Index API = ¼ (C spm / S spm +C NOx / S NOx + C SO2 / S SO2 + C CO / S CO ) x 100 API =¼ (180.2 / / / / 20) x 100 API = ~ 90 60

61 Air Pollution Indices or Index Index Value Remark 0-25 Clean Air Light Air pollution Moderate Air Pollution Heavy Air Pollution >100 Severe Air Pollution Other Rating:- Good, Acceptable, Satisfactory, Unsatisfactory, Unhealthy, Light Moderate, Heavy, Normal, Severe, etc. 61

62 Wind Roses:- 1) Wind roses shows the prevailing direction of wind. 2) Defined as any diagram to show the distribution of wind direction experienced at a given location, over a considerable period. 3) Wind data ie Direction, duration, & intensity are graphically represented by a diagram called Wind Rose.

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65 Wind Roses:- 1) For accurate estimation of the dispersion of air pollutants in the atmosphere a knowledge of the frequency distribution of wind direction as well as wind speed is essential. 2) This type of information varies from city to city and varies for given city from month to month. 3) Wind data should be collected for a period of atleast 5 years and preferably of 1o years, so as to obtain an avg. data with sufficient accuracy.

66 Wind Rose Construction:- 1) The most common form consist of circle from which eight or sixteen lines emerge, one for each direction. 2) Length of each line is proportional to the frequency of wind from that direction and frequency of calm conditions is entered in the entre. 3) There are many variation in the construction of wind roses. Some indicates the range of wind speeds from each direction & some relates wind direction with other meteorological condition. 4) Line or bar extending to the north on the wind rose indicates the frequency of winds blowing from the north. 5) Wind rose diagram is prepared using an appropriate scale to represent % frequencies of wind direction and appropriate index shades, lines, etc. to represent various wind speeds. 6) Observation corresponding to wind speed below 1Km/Hr are recorded as Calm.

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69 Special Pollution Wind roses are:- 1) Precipitation Wind Rose 2) Smoke Wind Rose 3) SO2 Wind Rose 4) HC Wind Rose

70 TYPICAL SUMMARY QUESTIONS 1) Explain various zones of atmosphere by giving the details of temperature variation & gases present in each zone? 2) Explain with sketch the temperature variation with height in atmosphere and its impact on air pollution? 3) What are meteorological parameters and how they affect air pollution? Explain the effect of speed and wind direction? 4) What do you understand by Atmospheric Stability? Explain how atmospheric stability affects dispersion of pollutants. Also explain variation in atmospheric stability with temperature profile? 5) What is lapse rate? State and explain various types of lapse rate with temperature profile? Also state the atmospheric stability for each lapse rate? 6) Write a note on Plume Behavior under different atmospheric conditions or meteorological conditions? 70