Traffic Related Emissions of Traffic Related Emissions of Radical Precursors HCHO and HONO Radical Precursors HCHO and HONO in Los Angeles During CalNex in Los Angeles During CalNex S. Alvarez 1 , B. Rappenglück 1 , P.R. Veres 2,3 , J.M. Roberts 2 , A.K. Cochran 4 , C. Afif 5,6 , V. Michoud 5 , J.F. Doussin 5 , A. Borbon 5 , H. Osthoff 7 (1) Department of Earth and Atmospheric Sciences, University of Houston, TX/USA (2) NOAA Earth System Research Laboratory, Boulder, CO/USA (3) Max-Planck Institut für Chemie, Mainz, Germany (4) North Carolina Agricultural and Technical State University, Greensboro, NC/USA (5) LISA, UMR-CNRS 7583, Université Paris Est Créteil, Université Paris Diderot, Créteil, France (6) Department of Chemistry, Faculty of Science, Saint Joseph University, Beirut, Lebanon (7) University of Calgary, Canada
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Traffic Related Emissions of Radical Precursors HCHO and HONO in Los Angeles During CalNex
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Traffic Related Emissions ofTraffic Related Emissions ofRadical Precursors HCHO and HONORadical Precursors HCHO and HONO
in Los Angeles During CalNexin Los Angeles During CalNex
S. Alvarez1, B. Rappenglück1, P.R. Veres2,3, J.M. Roberts2, A.K. Cochran4, C. Afif5,6, V. Michoud5, J.F. Doussin5, A. Borbon5, H. Osthoff7
(1) Department of Earth and Atmospheric Sciences, University of Houston, TX/USA(2) NOAA Earth System Research Laboratory, Boulder, CO/USA
(3) Max-Planck Institut für Chemie, Mainz, Germany(4) North Carolina Agricultural and Technical State University, Greensboro, NC/USA
(5) LISA, UMR-CNRS 7583, Université Paris Est Créteil, Université Paris Diderot, Créteil, France(6) Department of Chemistry, Faculty of Science, Saint Joseph University, Beirut, Lebanon
(7) University of Calgary, Canada
• early morning
• midmorning
• afternoon
HCHO + UV HCO + H < 334 μm H + O2 + M HO2 + M HCO + O2 CO + HO2 NO + HO2 NO2 + OH
nm
HONO + UV OH + NO < 400 μm
nm
O3 + UV O(1D) + O2 < 310 nm O(1D) + H2O 2OH
– Sources of OH
– Secondary formation through photochemical breakdown of anthropogenic and biogenic VOCs.
– Primary emission through incomplete combustion. Potential sources:• mobile sources (traffic exhaust)• point sources (in petrochemical production).
Formation of Formaldehyde (HCHO)Formation of Formaldehyde (HCHO)
HONO vs CO (weekdays)4:30-6:00 am and 8:00-10:00 pm
(PAN < 300 ppt)
CalNex-Pasadena “higher”CalNex-Pasadena “higher”
– HCHO and HONO traffic related emissions during CalNex;preliminary results:
• Increase of HCHO and HONO during rush hour(s)
• HCHO <> CO ratio: slope around 3.5 - 4.9 pptv HCHO/ 1 ppbv CO• HONO <> CO ratio: slope around 3.3 - 4.2 pptv HONO/ 1 ppbv CO
• Higher than in roadside study in Houston But: in Houston: PAN < 50 ppt; in CalNex-Pasadena: PAN < 300 ppt)- CalNex-Pasadena: more aged air masses?- Traffic composition? - Traffic flow?
– HCHO and HONO traffic related emissions during CalNex;preliminary results:
• Increase of HCHO and HONO during rush hour(s)
• HCHO <> CO ratio: slope around 3.5 - 4.9 pptv HCHO/ 1 ppbv CO• HONO <> CO ratio: slope around 3.3 - 4.2 pptv HONO/ 1 ppbv CO
• Higher than in roadside study in Houston But: in Houston: PAN < 50 ppt; in CalNex-Pasadena: PAN < 300 ppt)- CalNex-Pasadena: more aged air masses?- Traffic composition? - Traffic flow?
– What next?
• HONO: final QA, inclusion of additional HONO data (NOAA)• PAN: filling gaps in PAN data (GC?)• Merging with VOC and NOx data• Source apportionment• Comparison with MOBILE6 / MOVES2010 traffic emissions modeling
– HCHO and HONO traffic related emissions during CalNex;preliminary results:
• Increase of HCHO and HONO during rush hour(s)
• HCHO <> CO ratio: slope around 3.5 - 4.9 pptv HCHO/ 1 ppbv CO• HONO <> CO ratio: slope around 3.3 - 4.2 pptv HONO/ 1 ppbv CO
• Higher than in roadside study in Houston But: in Houston: PAN < 50 ppt; in CalNex-Pasadena: PAN < 300 ppt)- CalNex-Pasadena: more aged air masses?- Traffic composition? - Traffic flow?
– What next?
• HONO: final QA, inclusion of additional HONO data (NOAA)• PAN: filling gaps in PAN data (GC?)• Merging with VOC and NOx data• Source apportionment• Comparison with MOBILE6 / MOVES2010 traffic emissions modeling
Acknowledgements: - NOAA: Roberts et al., Borbon et al., Osthoff- JJJ: Alvarez, Rappenglück