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Impacts of Ethanol Fuel on PM Impacts of Ethanol Fuel on PM Concentrations in Northern Concentrations in Northern

California during a Winter EpisodeCalifornia during a Winter Episode

1Planning and Technical Support DivisionAir Resources Board

California Environmental Protection Agency

2Department of Land, Air and Water ResourcesUniversity of California at Davis

Paul Livingstone1, Ajith Kaduwela1,2, Kemal Gürer1, Paul Allen1, and Luis Woodhouse1

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DISCLAIMERDISCLAIMER

The content of this presentation does not necessarily reflect the views and policies of the California Air Resources Board, nor does mention of trade names or commercial products constitute endorsement or recommendation for use.

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OutlineOutline

• Introduction• Modeling Approach• Results and Discussions

– Emissions– Background concentrations– Changes of O3 due to ethanol– Changes of Secondary Inorganic Aerosols

(SIA) due to ethanol

• Summary

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Introduction

• Ethanol in light-duty vehicle fuel may– reduce emissions of NOx, primary PM, CO2, and

primary air toxics– increase emissions of ethanol, its combustion

products, CH4, and the price of corn-based food products

• Impact of ethanol blends on ozone– Increased ozone exposure in LA (Jacobson, 2007,

ES&T)

• Impact of ethanol blends on secondary PM?

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Scope of this StudyScope of this Study

• Chose San Joaquin Valley (SJV) of California during the winter– Secondary PM high in SJV during the winter– Already have a reasonable base CMAQ simulation for the winter

2000

• No future projections, but followed Jacobson (2007, ES&T) closely

• Assumed all light-duty vehicles in California could have used an ethanol blend (E85) in 2000

• Assumed no change in primary particulate matter and secondary organic aerosol concentrations due to E85 use

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The San Joaquin Valley

• One of the most productive agricultural regions in the world – Cadillac Dessert

• Major goods movement corridors

• Oil production in the southern Valley

• Air Quality: Second most polluted area in the US and second most studied area in the world

• Ozone pollution in the summer and PM pollution in the winter (but the annual PM standard is more restrictive)

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Major field studies • 1970: Project Lo-Jet (identified summertime low-level jet and Fresno eddy)• 1972: Aerosol Characterization Experiment (ACHEX, first TSP chemical composition

and size distributions)• 1979-1980: Inhalable Particulate Network (first long-term PM2.5 and PM15 mass and

elemental measurements in Bay Area, Five Points)• 1978: Central California Aerosol and Meteorological Study (seasonal TSP elemental

composition, seasonal transport patterns)• 1979-1982: Westside Operators (first TSP sulfate and nitrate compositions in western

Kern County)• 1984: Southern SJV ozone study (first major characterization of O3 and meteorology in

Kern County)• 1986-1988: California Source Characterization Study (quantified chemical composition

of source emissions)• 1988-89: Valley Air Quality Study (first spatially diverse, chemical characterized, annual

and 24-hour PM2.5 and PM10 seasonal)• Summer 1990: San Joaquin Valley Air Quality Study/Atmospheric Utilities Signatures

Predictions and Experiments (SJVAQS/AUSPEX, first central California regional study of O3 and PM2.5) – Also known as SARMAP (SJVAQS/AUSPEX Regional Modeling Adaptation Project)

• Winter 1995: CRPAQS Pilot Study (IMS95, first sub-regional winter study)• December 1999 to February 2001: CRPAQS and CCOS (first year-long, regional-scale

effort)• December 1999 to present: Fresno Supersite (first multi-year experiment with advanced

monitoring technology)

Prof. John Watson, DRI

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Seasonality of OSeasonality of O33 and PM and PM2.52.5

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120

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Jul-0

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8-Hour Ozone Max (ppb) Daily PM2.5 (ug/m3)

Fresno – 1st Street

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Measurements

162 Air Quality Stations

365 Meteorology Stations

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Modeling ApproachModeling Approach

• Used data from California Regional PM10/PM2.5 Air Quality Study (CRPAQS)– www.arb.ca.gov/ccaqs

• Episode: – December 25-30, 2000– Spin-up: December 22-24, 2000

• MM5 meteorology with FDDA (NWS data)• CARB 2002 emissions inventory back-casted to

2000 (but not the inventory used in recent SIPs)• CMAQ with SAPRC-99 chemistry and ‘ae4’

aerosol module

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Emission Scaling Factors for Emission Scaling Factors for Ethanol BlendEthanol Blend

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Surface EmissionsSurface Emissions

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Background ConcentrationsBackground Concentrations

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Ethanol Effects on O3Ethanol Effects on O3

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Surface SIA ComponentsSurface SIA Components

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Surface Fine PMSurface Fine PM

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Ethanol Effects on SIAEthanol Effects on SIA

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Ethanol Effects on SIAEthanol Effects on SIA

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Summary• CMAQ was applied to a CRPAQS winter

episode, to simulate the impact of hypothesized use of an ethanol blend on SIA components

• We observed slight increases in O3 concentrations

• The ethanol blend was found to reduce SIA in most area of the San Joaquin Valley in California during a winter episode.

• Ethanol blends is just one component of a larger control strategy. The conclusions can change in that context.

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International Aerosol Modeling International Aerosol Modeling Algorithms (IAMA) ConferenceAlgorithms (IAMA) Conference

• Bi-annual in-depth look at the inner-workings of aerosol models (complements the annual CMAS Meeting)

• Wednesday, December 5th – Friday, December 7th, 2007 (just before the AGU meeting in San Francisco)

• University of California at Davis• Impressive list of U.S. and international invited

speakers• Information at http://airquality.ucdavis.edu/