Sierra Ozone Studies

EPA Grant Number: R825433C065
Subproject: this is subproject number 065 , established and managed by the Center Director under grant R825433
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: EERC - Center for Ecological Health Research (Cal Davis)
Center Director: Rolston, Dennis E.
Title: Sierra Ozone Studies
Investigators: Carroll, John
Institution: University of California - Davis
EPA Project Officer: Packard, Benjamin H
Project Period: June 30, 1996 through June 30, 1999
RFA: Exploratory Environmental Research Centers (1992) RFA Text |  Recipients Lists
Research Category: Targeted Research


The primary objectives of this project are to document the exposure and impacts of air pollutants on the forests of the western slope of the Sierra Nevada and to identify biochemical indicators of exposure to pollutants and other stresses. The choice of pollutants studied is governed either by their potential for damaging the forests directly (e.g. ozone) or because they act as surrogates or tracers for a variety of potentially damaging substances (e.g. selected organic compounds).


Analyses of atmospheric data performed to date indicate that local exposure patterns in complex topography do not follow simple diurnal variations. Meteorological patterns observed at some sites are typical for the terrain: warm afternoons with moderately strong upslope (west or southwesterly flows) and cool nights with weak downslope flows. Given this pattern, peak ozone concentrations occur in the afternoon hours when the upslope flows will have transported ozone and its precursors from the sources in the Central Valley. At some sites a strong diurnal pattern is absent and peak values are found at night. For example, the highest concentrations observed at one site (approximately I 10 parts per billion volume) occur around midnight when northeasterly (downslope) winds dominate. Currently, the investigators are using a larger scale model to simulate summertime regional transport of "tracers" from major urban areas (L.A.; Bakersfield, Fresno, San Francisco and Sacramento) to the Sierra and sensitive areas to the east of California. The model is a mesoscale forecast model developed at Davis which uses daily weather observations, National Meteorological Center analyses and forecast data as initial and boundary conditions. The current study will evaluate transport for the continuous period of July 1, 1995 through September 30, 1995. This period overlaps a multi- week regional air quality study sponsored by the CARB in Southern California and several UCD flights east of Sacramento. These observations will be important for evaluating this model's performance.

Expected Results:

Investigators will use data from a series of previous studies in which meteorology and/or ozone exposure were monitored and symptoms of ozone injury to selected pine species were quantified at eleven sites in the Sierra Nevada. Since plant respiration plays a key role in determining how much material enters the leaves, having a method to estimate this ingestion rate using meteorological conditions surrounding the trees is important. Investigators expect to refine methods for distinguishing between exposure and dosage using estimates of stomatal conductance to calculate daily dosages. The consensus of the research community is that ozone damage occurs primarily to the cells within the stomates as a result of respiration of polluted air. Therefore, the stomata] conductance regulates the rate of ingestion of ozone. We are continuing our search for a means to use local meteorological conditions to estimate the variation of this conductance. A comprehensive set of respiration and stomatal conductance measurements in Jeffery and Ponderosa pines is available to allow development of a stomatal conductance estimator for converting exposure to dosages.

Supplemental Keywords:

California, environmental stress, forests, Sierra Nevada, biochemistry, ozone, ecological indicator, ecosystem modeling., RFA, Toxics, Ecosystem Protection/Environmental Exposure & Risk, Ecosystem/Assessment/Indicators, Ecosystem Protection, Ecological Effects - Environmental Exposure & Risk, EPCRA, Ecological Indicators, air, air pollutants, stressors, forest ecosystems, ozone

Progress and Final Reports:

  • 1996
  • 1997
  • Final

  • Main Center Abstract and Reports:

    R825433    EERC - Center for Ecological Health Research (Cal Davis)

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R825433C001 Potential for Long-Term Degradation of Wetland Water Quality Due to Natural Discharge of Polluted Groundwater
    R825433C002 Sacramento River Watershed
    R825433C003 Endocrine Disruption in Fish and Birds
    R825433C004 Biomarkers of Exposure and Deleterious Effect: A Laboratory and Field Investigation
    R825433C005 Fish Developmental Toxicity/Recruitment
    R825433C006 Resolving Multiple Stressors by Biochemical Indicator Patterns and their Linkages to Adverse Effects on Benthic Invertebrate Patterns
    R825433C007 Environmental Chemistry of Bioavailability in Sediments and Water Column
    R825433C008 Reproduction of Birds and mammals in a terrestrial-aquatic interface
    R825433C009 Modeling Ecosystems Under Combined Stress
    R825433C010 Mercury Uptake by Fish
    R825433C011 Clear Lake Watershed
    R825433C012 The Role of Fishes as Transporters of Mercury
    R825433C013 Wetlands Restoration
    R825433C014 Wildlife Bioaccumulation and Effects
    R825433C015 Microbiology of Mercury Methylation in Sediments
    R825433C016 Hg and Fe Biogeochemistry
    R825433C017 Water Motions and Material Transport
    R825433C018 Economic Impacts of Multiple Stresses
    R825433C019 The History of Anthropogenic Effects
    R825433C020 Wetland Restoration
    R825433C021 Sierra Nevada Watershed Project
    R825433C022 Regional Transport of Air Pollutants and Exposure of Sierra Nevada Forests to Ozone
    R825433C023 Biomarkers of Ozone Damage to Sierra Nevada Vegetation
    R825433C024 Effects of Air Pollution on Water Quality: Emission of MTBE and Other Pollutants From Motorized Watercraft
    R825433C025 Regional Movement of Toxics
    R825433C026 Effect of Photochemical Reactions in Fog Drops and Aerosol Particles on the Fate of Atmospheric Chemicals in the Central Valley
    R825433C027 Source Load Modeling for Sediment in Mountainous Watersheds
    R825433C028 Stress of Increased Sediment Loading on Lake and Stream Function
    R825433C029 Watershed Response to Natural and Anthropogenic Stress: Lake Tahoe Nutrient Budget
    R825433C030 Mercury Distribution and Cycling in Sierra Nevada Waterbodies
    R825433C031 Pre-contact Forest Structure
    R825433C032 Identification and distribution of pest complexes in relation to late seral/old growth forest structure in the Lake Tahoe watershed
    R825433C033 Subalpine Marsh Plant Communities as Early Indicators of Ecosystem Stress
    R825433C034 Regional Hydrogeology and Contaminant Transport in a Sierra Nevada Ecosystem
    R825433C035 Border Rivers Watershed
    R825433C036 Toxicity Studies
    R825433C037 Watershed Assessment
    R825433C038 Microbiological Processes in Sediments
    R825433C039 Analytical and Biomarkers Core
    R825433C040 Organic Analysis
    R825433C041 Inorganic Analysis
    R825433C042 Immunoassay and Serum Markers
    R825433C043 Sensitive Biomarkers to Detect Biochemical Changes Indicating Multiple Stresses Including Chemically Induced Stresses
    R825433C044 Molecular, Cellular and Animal Biomarkers of Exposure and Effect
    R825433C045 Microbial Community Assays
    R825433C046 Cumulative and Integrative Biochemical Indicators
    R825433C047 Mercury and Iron Biogeochemistry
    R825433C048 Transport and Fate Core
    R825433C049 Role of Hydrogeologic Processes in Alpine Ecosystem Health
    R825433C050 Regional Hydrologic Modeling With Emphasis on Watershed-Scale Environmental Stresses
    R825433C051 Development of Pollutant Fate and Transport Models for Use in Terrestrial Ecosystem Exposure Assessment
    R825433C052 Pesticide Transport in Subsurface and Surface Water Systems
    R825433C053 Currents in Clear Lake
    R825433C054 Data Integration and Decision Support Core
    R825433C055 Spatial Patterns and Biodiversity
    R825433C056 Modeling Transport in Aquatic Systems
    R825433C057 Spatial and Temporal Trends in Water Quality
    R825433C058 Time Series Analysis and Modeling Ecological Risk
    R825433C059 WWW/Outreach
    R825433C060 Economic Effects of Multiple Stresses
    R825433C061 Effects of Nutrients on Algal Growth
    R825433C062 Nutrient Loading
    R825433C063 Subalpine Wetlands as Early Indicators of Ecosystem Stress
    R825433C064 Chlorinated Hydrocarbons
    R825433C065 Sierra Ozone Studies
    R825433C066 Assessment of Multiple Stresses on Soil Microbial Communities
    R825433C067 Terrestrial - Agriculture
    R825433C069 Molecular Epidemiology Core
    R825433C070 Serum Markers of Environmental Stress
    R825433C071 Development of Sensitive Biomarkers Based on Chemically Induced Changes in Expressions of Oncogenes
    R825433C072 Molecular Monitoring of Microbial Populations
    R825433C073 Aquatic - Rivers and Estuaries
    R825433C074 Border Rivers - Toxicity Studies