air quality slides set

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Air Quality (Slide Set 1)

Virendra Sethivsethi@iitb.ac.in

x7809

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Class Exercise

• How many grams of Sulphur, if burnt in P C Saxena Auditorium, would pose a health risk to you ?

• Given : Regulatory Limit for SO2 in Ambient Air is – 80g/m3 (0.03 ppm) for annual average– 1300 g/m3 (0.5 ppm) for 3 hour average

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Results (last year)

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ES 200 Autumn 2011 PC Saxena Volume

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Results (this year)

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Conclusions

• All JEE’s are equal

• There is always a JEE topper

• Nothing can substitute measured measurables

• 17.5 X 23.8 X 3.5 = 1458 m3

• (17.8 - 26.9)X 18.6 X 3.5 = 1160 m3

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Winners TBD

• 10D070064 SACHIN KUMAR 1460 m3

• 08007021ADITYA AGRAWAL1150 m3

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Implications

• Shut down of industries and businesses

• Investment in infrastructure

• DOUBT is introduced

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How do we manage Air Quality ?

• At the source itself– Industry– Vehicles– Dust– Home cooking

• After the source– Dispersion and Mixing

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Mixing/Dispersion

• Meteorology– Vertical

• Temperature– Lapse Rate

– Horizontal• Wind

– Speed – Direction

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Dispersion – Gaussian Plume

WIND

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Wind Rose

http://www.epa.gov/ttn/naaqs/ozone/areas/wind.htm#dlfi

1 knot = 1.82 km/hr

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• Wind roses are divided into 16 wind directions

• Each wind direction is divided into wind speeds

• As the percent of time the wind blows from a particular directions gets larger, the portion of the bar representing the wind speed gets larger both in length and width

13http://www.ldeo.columbia.edu/edu/dees/ees/climate/slides/atmprofile.gif

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Lapse Rates

• Atmosphere cools with height– What rate ?

• Dry (Adiabatic) 10°C/km• Wet (Adiabatic) 6°C/km

– (Release of heat with condensation)

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Definitions

• Environmental Lapse Rate (Actual)– Actual temperature profile – Balloon with height and temperature sensors

• Adiabatic Lapse Rate– A parcel of air moved in short enough time

that there is no heat exchange between the parcel and the surrounding atmosphere

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ACTUAL

ADIABATIC (1°C/100 m)

1000 m (say)

20 °C19 °C18 °C

20 °C Air Parcel

19 °C Air Parcel at 1100 m

1100 m

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ADIABATIC (1°C/100 m)

1000 m (say)

20 °C 21°C 22 °C

20 °C Air Parcel

21 °C Air Parcel at 1100 m

1100 m

900 m

ACTUAL

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ADIABATIC (1°C/100 m)

1000 m (say)

20 °C19.5 °C19°C

20 °C Air Parcel

19 °C Air Parcel at 1100 m

1100 m

ACTUAL

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WIND

Adiabatic

Actual

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ScenariosAdiabatic

ActualH

eig

ht

Temperature

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ScenariosAdiabatic

ActualH

eig

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Temperature

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ScenariosAdiabatic

ActualH

eig

ht

Temperature

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Stability

http://www.tpub.com/content/aerographer/14312/css/14312_47.htm

Wet Lapse Rate

Dry Lapse Rate

Average

Unstable

Stable

Height

Temperature

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Match the Profile

Unstable

Stable

Plumes (a) (b) (c) (d)

(Adapted from Masters, 1997)

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Match the Profile

Unstable

Stable

Plumes (a) (b) (c) (d)

(Adapted from Masters, 1997)

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Review

Dispersion and Mixing Influenced by :• Wind

– Speed– Direction– Wind Rose

• Temperature Lapse Rates– Dry adiabatic– Wet Adiabatic– Stability

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First Home Assignment• 1. Review the film smog.inc at :

http://www.cese.iitb.ac.in/ES200/SMOG_INC/

• 2. Review the paper by Molina and Molina (2004) at : http://www.cese.iitb.ac.in/ES200/MolinaAndMolinaCriticalReviewJAWMA2004.pdf

• 3. You have been appointed as the new In-charge for air quality management in your home city.

– Your first assignment is to write a proposal to MoEF for management of air quality of your city using traffic management.

– The solutions are to include short term and long term plans.

– You may submit a map and key data (or the need for specific data) to support your proposal.

– The proposal may be limited to 1000-1500 words. Please include references (as URL’s and/or journals/reports.

– (If you think that there is no vehicular pollution problem in your home city/village, justify it, and then choose Mumbai as the study city).

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Air Pollution• Concentration

– mass of pollutant / volume of air– number of particles / volume of air– opacity– absorption

• Duration – hours to days to years

• Criteria Pollutants – Primary (FIVE)

• SOx• NOx• CO• PM-10• Particulate Lead

– Secondary (ONE)• Ozone

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Stopped in Nose

Respirable

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Physical Nature of Particulate Emissions from Engines

Typical Engine Exhaust Size Distribution both Mass and Number Weightings (Source: Kittelson et al. 1999)

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Diluted Diesel Exhaust: Particle Number vs. Mass

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Particle Size [nm]

Particle Number [P/cm3]

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Particle Mass [mg/m3]

Courtesy : TSI Inc.

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CO

LLE

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/ R

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OV

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FIC

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PARTICLE DIAMETER

1 m

39Source: Flagan and Seinfeld, 1988

Particle formation in coal combustion

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Physical Nature of Particulate Emissions from Engines

Typical Engine Exhaust Size Distribution both Mass and Number Weightings (Source: Kittelson et al. 1999)

PM2.5 PM10