Role of Ammonia in Formation of Secondary Particulate Matter: A Study from Kanpur, India Mukesh Sharma, Shyam Kishore, Tejas, and Sailesh Environmental Engineering and Management Program Department of Civil Engineering Indian Institute of Technology Kanpur, Kanpur 208016, India Indoflux Meeting Chennai July 12-16, 2006
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Role of Ammonia in Formation of Secondary Particulate Matter: A Study from Kanpur, India
Role of Ammonia in Formation of Secondary Particulate Matter: A Study from Kanpur, India. Mukesh Sharma, Shyam Kishore, Tejas, and Sailesh Environmental Engineering and Management Program Department of Civil Engineering Indian Institute of Technology Kanpur, Kanpur 208016, India - PowerPoint PPT Presentation
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Role of Ammonia in Formation of Secondary Particulate Matter: A Study from Kanpur, India
Mukesh Sharma, Shyam Kishore, Tejas, and Sailesh
Environmental Engineering and Management ProgramDepartment of Civil Engineering
Indian Institute of Technology Kanpur, Kanpur 208016, India
Indoflux Meeting Chennai July 12-16, 2006
Case Study – Secondary Particle Formation
Should Air Quality Measurements be Subset of Indo-flux Measurements – if yes, how?
BACKGROUND
National Air Quality Program Suggests two Issues
o Consistently high particulate matter( PM) levelso Consistently rising levels of oxides of nitrogen (NOx)______________________________________________o Ozoneo VOCs, BTX, PAHs, Dioxins, Metalso Water Soluble Ions
0
100
200
300
400
500
600
700
SO2 NOX SPM
DELHI KOLKATA MUMBAI KANPUR
ug
/m3
Delhi
Mumbai Kolkata
Kanpur
Summer PM10 Variation
Summer NOx Variation
Time Series : 1998-2004 New Delhi
Average PM10: 400 ug/m3
d[NOx]/dt = 10 ug/m3-yr
NOx , SO2and PM10 Interlinked
Objectives of the Case - study
to understand the role of NO2, NH3, SO2, HNO3, temperature and humidity in formation of particulate sulfate and nitrate.
JHNO3 is the photolytic rate constant for HNO3, and depends on latitude, season and solar zenith angle. It is calculated as the product of actinic flux, quantum yield and absorption cross section area. It is corrected for every season. Concentration of [OH] depends on photolysis rate of O3.
2 3 5 3
3 1
[ ] [ ][ ]
[ ][ ]
HNONO J k HNO OH
HNO k OH M
At Equilibrium
Conclusion:HNO3 showed seasonal variation, with highest concentration in summer compared to winter and post monsoon.
Photochemical activity and shift of equilibrium from particulate phase ammonium nitrate to gas- phase ammonia and nitric acid.
The equilibrium ratio is highest in summer due to high solar radiation, which leads to higher concentration of OH radical, thereby more formation of HNO3 as determined in Table
Contd..
Species Seasonal rate constant (s-1)
PostMonsoon
Winter Summer
JHNO3 2.4× 10-7 3.1× 10-7 4.3× 10-7
k5 1.5× 10-7 1.8× 10-7 2.2× 10-7
Equilibrium ratio
Seasons
PostMonsoon
Winter Summer
Ratio 0.039 0.051 0.065
Pitts and Pitts 1986
2 3 5 3
3 1
[ ] [ ][ ]
[ ][ ]
HNONO J k HNO OH
HNO k OH M
Site NH3 Levels (ppbv) Ref.
New Delhi 47.3 ± 13.6 Kapoor et al. (1992)
Mumbai 50.7 Zuthshi et al. (1970)
Bay of Bengal 16.4 ± 3.5 Parmar et al. (2000)
Sarni 2.3 ± 0.4 Khemani et al. (1987)
Kanpur (overall) 26.3 ± 4.6 Present Study
Sampling site HNO3 NH3
PostMonsoon(µg/m3)
Summer(µg/m3)
Winter(µg/m3)
PostMonsoon(µg/m3)
Summer(µg/m3)
Winter(µg/m3)
Rampur,India - 1.3 0.3 - 2.5 8.1
Dayalbagh ,India 2.35 2.1 1.0 11.59 10.8 8.9
Cairo ,Egypt - 6.70 1.14 - - -
IITK,India - 6.90 2.39 - 18.69 19.09
Comparison… Ammonia Plays Vital Role
Where is all ammonia coming from?Global Atmospheric Sources of Ammonia