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 , 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 oConsistently high particulate matter( PM) levels oConsistently rising levels of oxides of nitrogen (NO x ) ______________________________________________ oOzone oVOCs, BTX, PAHs, Dioxins, Metals oWater Soluble Ions ug/m 3 Delhi MumbaiKolkata Kanpur

Summer PM 10 Variation Summer NO x Variation Time Series : New Delhi Average PM10: 400 ug/m 3 d[NOx]/dt = 10 ug/m 3 -yr NO x, SO 2 and PM 10 Interlinked

Objectives of the Case - study to understand the role of NO 2, NH 3, SO 2, HNO 3, temperature and humidity in formation of particulate sulfate and nitrate. This is assessed in terms of: Inhalable PM 10, NO 2, HNO 3, NH 3 Water soluble ion: NO 3 -,SO 4 2-,Cl -,NH 4 +,Na +,K +,Ca 2+,Mg 2+ ; in PM 10

Agriculture Fields Vikash Nagar Population ~ 3 million

Formation of Secondary Particles (Seinfeld, 1996) NH 3 (g) + HNO 3 (g) ↔ NH 4 NO 3 (s) NaCl NO x HNO 3 NH 3 SOIL FINE MODE NITRATE (NH NO ) 4 3 SO 2 H SO 2 4 (NH ) SO 4 24 HCl NaCl HNO 3 NO x SOIL NH 3 FINE MODE NITRATE SO 2 H SO 2 4 (NH ) SO 4 24 COARSE MODE NITRATE CaCO3 (aq) +2 HNO3 (g) → Ca (NO3)2(s) +H2O +CO2 (g) Fine Mode Coarse Mode

Water Soluble Ions, NH 3 and HNO 3

RECAP Summer Vs Winter NO 3 -, SO 4 2-, NH 4 +, K + significantly high in winter Ca 2+, Mg 2+, HNO 3, PM 10 significantly high in summer Winter: Day Vs Night NO 3 -, SO 4 2-, NH 4 +, K +, PM 10, HNO 3 significantly high in winter day Ca 2+, Mg 2+, Cl -, Na +, NH 3 no significant difference Summer: Day Vs Night SO 4 2-, NH 4 +, K +, significantly high in summer night N0 2,Ca 2+, Mg 2+,PM 10, HNO 3 NH 3 significantly high in summer day NO 3 -, Cl -, Na + no significant difference

Ionic balance for summer and winter µ equ/m 3  Difference in cation and anion: 17% in winter and 24% in summer  carbonate and bicarbonate not measured and other unknown anions

Correlation Analysis WinterSummer NO 3, SO 4 with NH 4 Not with Ca, Mg Fine Mode PM Formation SO 4 with NH 4 Fine Mode PM Formation No Coarse Mode PM Formation NO 3 with Ca, Mg Coarse Mode PM Formation Statistical Significant Correlation (n = 17 summer; n = 18 winter)

Science… Comparison of NH 4 + and SO 4 2- ion with stoichiomertic ratio of (NH 4 ) 2 SO 4. (2:1 line reference line represents complete SO 4 2- neutralization ). Comparison of excessNH 4 + and NO 3 - ion with stoichiomertic ratio of (NH 4 )NO 3. (The 1:1 line reference line represents complete NO 3 - neutralization). Winter Analysis

NH 3 and HNO 3 Equilibrium (summer) [NH 3 (g)] =27.72 ppb, [HNO 3 (g)]=2.69 ppb and RH =41.98 %. RH < RHD (deliquescence), NH 4 NO 3 is in solid form But…. for NH3 (g) + HNO3 (g) ↔ NH4NO3 (p) [NH3][HNO3] > K of reaction : [NH3][HNO3] = 74.56ppb 2 K( Calculated) = ppb 2 Formation of NH 4 NO 3 will be lower in summer

NH 3 and HNO 3 Equilibrium( winter) [NH 3 (g)] =26.74 ppb;[HNO 3 (g)]=0.90ppb RH = 85.35%; RHD (deliquescence)= 68.29% RH > RHD, NH 4 NO 3 is in aqueous form NH3 (g) + HNO3 (g) ↔ NH4 + + NO3 - T = 290 Kelvin, K = 3.51 ppb 2 [NH 3 (g)] [HNO 3 (g)]= 24ppb 2 > K NH 4 NO 3 Formation favored and in (aq) form US Study (Baek and Aneja, 2004) T= 297 Kelvin, K = ppb 2 [NH 3 (g)][HNO 3 (g)] = 32.2 ppb 2 > K [NH 3 ] = 78 ppb [HNO 3 ] = 0.41 ppb

Nitrogen Conversion ratio  Nitrogen conversion ratio: F n = ( PNO 3 - +GNO 3 - )/ (NO 2 + PNO 3 - +GNO 3 - ) PNO 3 - particulate nitrate as NO 2,µg/m 3 ; GNO 3 - gaseous nitrate concentration NO 2,µg/m 3 ; NO 2 gas phase NO 2 concentration, µg/m 3 F n (summer) = 44 % GNO 3 >> PNO 3 F n (winter) = 52% PNO 3 >> GNO 3 Science??

HNO 3 and NH 3 Seasonal variation NO 2 (g) + OH. (g) → HNO 3 (g) (1) O 3 (g) + hν → O (1D) (g) + O 2 (g) (2) O (1D) + H 2 O (g) → 2 OH. (g) (3) HN0 3 + hv → NO 2 +OH. (4) HNO 3 + OH →NO 3 +H 2 O (5) J HNO3 is the photolytic rate constant for HNO 3, 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 O 3. At Equilibrium

Conclusion:  HNO 3 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 HNO 3 as determined in Table Contd.. SpeciesSeasonal rate constant (s -1 ) Post Monsoon WinterSummer J HNO3 2.4× × × k5k5 1.5× × × Equilibrium ratio Seasons Post Monsoon WinterSummer Ratio Pitts and Pitts 1986

SiteNH 3 Levels (ppbv)Ref. New Delhi47.3 ± 13.6Kapoor et al. (1992) Mumbai50.7Zuthshi et al. (1970) Bay of Bengal16.4 ± 3.5Parmar et al. (2000) Sarni2.3 ± 0.4Khemani et al. (1987) Kanpur (overall)26.3 ± 4.6Present Study Sampling siteHNO 3 NH 3 Post Monsoon (µg/m 3 ) Summer (µg/m 3 ) Winter (µg/m 3 ) Post Monsoon (µg/m 3 ) Summer (µg/m 3 ) Winter (µg/m 3 ) Rampur,India Dayalbagh,India Cairo,Egypt IITK,India Comparison… Ammonia Plays Vital Role

Where is all ammonia coming from? Global Atmospheric Sources of Ammonia Sources:

India Livestock Population World livestock population Vs India: 2003 in million nos AnimalsWorldIndia% in India Cattle Buffaloes Sheep Goats Pigs Horses Mules Asses Camels PoultryNA489NA Source:

Winter Post Monsoon Summer

Flux Measurement Project – A Unique Opportunity 3 – M Multi - Objective Multi – User Multi – Parameter _______________________________________ Act as Background AQ Stations – Time Series/Trend Analysis Dispersion/Deposition Studies Criteria Pollutants VOCs WSI – Source Apportionment, Global Warming Model, Atmospheric Chemistry

Acknowledgements…. We gratefully acknowledge -- INDO-U.S. SCIENCE AND TECHNOLOGY FORUM -- DST, New Delhi -- Prof. Ramesh and Workshop Organizers