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8/14/2019 SARP_mhuang

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Dairy Farm EmissionDairy Farm EmissionStudy in NOx LimitedStudy in NOx Limited

Min HuangUniversity of Iowa

SARP, 08/12/2009, Irvine


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Overview

Background andObjectives

Data Collection andAnalysis

Results


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Background

O3=VOC+NOx+sunlight introposphere

Standards:State 1-hr: 0.09 ppm; State 8-

hr: 0.07 ppm; National 8-hr:

0.075ppmCentral valley has well

documented O3 problems over

the past decades


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Total VOC emissionsignificantly droppedfrom on roademissions but slightlyfrom other categories

The gradients over

http://www.arb.ca.gov/aqd/almanac/almanac.htmhtt ://www.e a. ov/c i-

EPA NEI CARB


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Why SARP successful forbio enic emission stud

Fewfacilitiesemission

http://www.epa.gov/air/emissions/where.htm


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2008- 2009-

Less fire



8/26Continuous low


Flight FlightJulian time

Altit

ude


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Objectives

Determine the spatial distributionof VOCs in central valley,particularly ethanol and

acetaldehyde from dairy farms.-- emission inventories

improvement

Correlate the VOC concentrationsto ozone production in central


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Data Collection and

VOCs (C1 ~C10)Whole Air Sampler

gas chromatography +detectors + Chromeleonmodification

NOx & O3STEM model forecast


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Results-VOC spatialdistribution

p

Total C1~ C10 from


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Results- Ethanol spatialdistribution

pp

Ethanol

concentrations


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Yang et

VOC emissionsin

NEI fromlivestock &fertilizer by

county(ton/yr)

Tulare 5008

Stanislaus4561

Merced 3220

HIGHER PEAKS in summer

http://www.epa.gov/air/emissions/w


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Results-VOC vs. Ozone

Fligh

Fligh

After removing diurnal circles

byexponential regression for O3

NOT


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VOC vs. Ozone

Different reactivity of VOCs toproduce O3

Meteorology - transport & mixing,etc

O3=VOC+NOx+sunlightratio of VOC/NOx affects O3

production The San Joaquin Valley of

California is a region wheresecondary pollutants will respondweakly or not at all to continued

anthropogenic VOC controls while


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VOC vs. Ozone

Definition of VOC/NOx sensitivebased on ratio

FlexibleRule of thumb 10ppbC/ppbv

(Molina)Consider model uncertainties and

rural characteristics, in this study - < 10 VOC sensitive 10 ~ 20 Transitional (both


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Case study flight 1

High NOx due to diurnal cycle, excluded


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Case study flight 1

Most areas with highethanol+acetaldehyde % and totalVOCs are transitional or NOx limited

Why still need to control VOCs?What if reducing ethanol +acetaldehyde by 75 % ?


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Case study flight 1

Most of them move to transitionalarea or VOC sensitive areas afterreduction

Ratios can decrease more because ofthe reduction to other VOCs of thesame sources

Maximum Incremental Reactivity: (gO3/g C)

Ethanol: 1.69 (life time 4 days)


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Conclusion

Ethanol was observed high in Fresnosurrounding areas mainly due todairy farms emission, which account

a large portion of VOC in these areasNo direct correlations between VOC-

O3

Most of these rural areas possiblybelong tonon-VOC limited

Reducing dairy farm ethanol

emissions can still be efficient to O3


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Future work

Other VOC sources identificationEmission Inventory comparisons and

sensitivity studies

*What if we also have observed O3and NOx for the analysis ?

*75% ethanol control is a long way togo, Are there particular NOxsources/other VOC sources that canbe easier to control ?

*NOx or VOC sensitive in winter ?


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Acknowledgement

Blake/Rowland groupSARP emission team

Greg Carmichael, Scott Spak,Charles Stanier and modelingcolleagues @ U Iowa

NASA & NSERC


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THANK YOU!

QUESTIONS?


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Back up

Ethanol

Acetaldeh

yde


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Back upSTEM for ARCTASFlight 13

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