CHAPTER 5 - BIOGENIC EMISSIONS

1996 Emission Inventory for the Alamo Area Council of Governments Region

Biogenics Emissions Chapter Contents

 

Background

Natural source emissions can make a significant contribution to total volatile organic compound (VOC) and oxides of nitrogen (NOx) emissions. Estimating emissions of VOC and NOx from natural sources is an essential part of preparing an inventory of ozone precursors. Biogenic, geogenic, and lightning all represent natural sources of emissions which must be considered when estimating ozone inventories.

In the past, the impacts of biogenic VOC were not considered when ozone control strategies to limit emissions of either NOx or VOC were developed. Isoprene, one of the major constituents of biogenic emissions, is very photoreactive, making biogenic emissions an even more important source of VOC. Because of the interaction between NOx and VOC in terms of atmospheric ozone levels, biogenic emissions should be included in any inventory which will be used to predict or to monitor atmospheric ozone levels. Inclusion of biogenic emissions is essential for photochemical air quality modeling.

 

NATURAL SOURCE EMISSIONS VS. BIOGENIC SOURCE EMISSIONS

Biogenic Source Definition

Biogenic emissions are defined as all pollutants emitted from non-anthropogenic sources. Example sources include trees and vegetation, oil and gas seeps, and microbial activity. While fermentation produces biogenic emissions, gases from this process are included under either point or area sources.

Natural sources that are not biogenic sources include lightning, a source of nitric oxide (NO) and oil and gas seeps, which are sources of VOC, CH4 and hazardous air pollutants (HAPs). The estimated contributions of these sources may be significant when a modeling domain extends into areas that do not have a high anthropogenic contribution.

Vegetation is the predominant biogenic source of VOC and is typically the only source that is used to estimate biogenic VOC but VOC, NOx, and greenhouse gases such as methane (CH4), nitrous oxide (N2O), ozone (O3) and carbon dioxide (CO2) may originate from a variety of natural processes. Vegetation and soils, geological activity, lightning, and termites are just a few of the natural sources.

Microbial activity is responsible for the emission of NOx and the greenhouse gases of CO2, CH4, and N2O. Soil microbial activity is responsible for NOx and N2O emissions from agricultural lands and grasslands. CH4 is emitted through microbial action in waterlogged soils or in other anaerobic microenvironments. CO2 is released through the aerobic decay of biomass.

Modeling Biogenic Emissions

Three of the five alternative methods available for estimating biogenic emissions are computer models: PCBEIS2.3, BIOME and BEIS. An alternative to the above models involves collecting local information to substitute for defaults in any of the above models. The most commonly used options are more recent or more detailed land use or meteorological data and updated or additional emission factors and leaf biomass.

Standards for Modeling Biogenic Emissions

The USEPA's EIIP Biogenic Source Committee is responsible for developing preferred and alternate procedures for estimating biogenic and geogenic emissions. Specific pollutants and sources to be addressed include volatile organic compounds (VOC) from vegetation sources (e.g., plants, trees, grasses, and agricultural activity) and geogenic sources (e.g., geysers, seeps, and volcanoes), and oxides of nitrogen (NOx) from soil and lightning.

Natural (or biogenic) emissions of VOCs and NOx are important precursors of ozone, especially on a regional scale. Estimates of biogenic emissions are needed principally to conduct photochemical modeling for air quality planning purposes. But the inventory community is unable to routinely measure biogenic emissions. There are several tools to estimate non-anthropogenic emissions including the BEIS2 and BIOME models. To meet its objective of improving estimates of biogenic emissions, the committee has sought other procedures to improve estimates. The committee was not authorized to develop new methods and has instead concentrated on improvement of existing models.

BEIS

The BEIS-2 is the preferred method for air quality models using biogenic estimates, because it is the most scientifically advanced model for estimating biogenic ozone precursors. It can be used with several air quality models, and it estimates emissions of soil NOx, which can be an important source in many rural areas. The PCBEIS2 is also a preferred method when an emission estimate is needed for reporting purposes only.

 

BIOGENIC SOURCE EVALUATION-USING BEIS

When an inventory requires air quality analysis using a photochemical grid model, biogenic VOC and NOx need to be included with the modeled emissions. Under the Clean Air Act Amendments of 1990 (CAAA), the use of photochemical grid models is required for areas designated as nonattainment areas in the preparation of their SIPs. For these instances, the photochemical pollutant modeling applications should be used for entire urban areas or regions.

There are two preferred methods for estimating biogenic emissions of VOC and NOx, either BEIS-2 or PCBEIS2.3.

Environmental Correction Factors Studies indicate that biogenic emissions from most plant species are strongly temperature-dependent; isoprene emissions also vary with solar intensity. The emission factors used by BEIS-2 are standardized for full sunlight and 30° C. The BEIS-2 adjusts these emission factors to account for the effects of variations in ambient conditions. BEIS-2 also simulates the vertical variation of leaf temperature and sunlight within the forest canopy. The canopy model employed by BEIS-2 assumes that sunlight decreases exponentially through the hypothetical forest canopy; the rate of attenuation depends on the assumed leaf area index. Moisture stress is thought to have an important effect on emissions, but has not been quantified. The effect is not included in the BEIS-2 model.

 

PCBEIS2.3

In addition to emission modeling and projection inventory preparation where a version of the mainframe-based BEIS-2 would be used, other emission inventories may require biogenic emission estimates. Where the speciated and spatially allocated output of BEIS-2 is not necessary, or where a PC-based model is a more practical choice, PCBEIS2.3 is the recommended option.

The Personal Computer version of the Biogenic Emission Inventory System-2.3 (PCBEIS2.3), estimates speciated VOC from vegetation and NOx from soils. Output from this model can be used in an inventory report, as text. The most important issue in the use of a particular version of BEIS-2 is to match the meteorology and gridding to the air quality model that it will be used with. Aside from these differences, the scientific background of the BEIS-2 and PCBEIS2.3 models are the same.

PCBEIS2.3 provides outputs for two specific uses: An estimate of biogenic VOC and NOx emissions required for baseline emission inventories mandated by the CAAA; and Hourly estimates of biogenic VOC emissions needed for use with the Empirical Kinetic Modeling Approach (EKMA) model.

Biogenic emissions are output in kilograms per square kilometer per hour basis for each major species (isoprene, monoterpenes, NOx, and VOC). In addition to these primary uses, PCBEIS2.3 can be used for any application where biogenic VOC emission estimates at this level of detail are needed. Land use files and Biogenic Sources emission factors for biogenic VOC and NOx emissions are the same as those used in BEIS-2. BEIS-utilizes the most up-to-date landuse and emission factor information, and it takes into account the variation of emission rates due to temperature and light intensity.

Additional Details Regarding BEIS

The BEIS-2 is available in several versions that can be used with the ROM, RADM, CAMx and UAM models. The different BEIS-2 models are adaptations of the algorithm and land use files to the meteorology and grid cell sizes used in their respective air quality models. The format of the landuse file is the same as the format of the EPA's Biogenic Emission Landcover Database (BELD). The gridded landuse file is derived from the EPA's BELD. The development of the BELD is described in United States Land Use Inventory for Estimating Biogenic Ozone Precursor Emissions.¹ The BELD provides landcover data for every county in the contiguous United States. BEIS-2 is adapted to be used with the following quality models: Regional Oxidant Model (ROM), the Regional Acid Deposition Model (RADM), Comprehensive Air Quality Model with extensions (CAMx), and the Urban Airshed Model (UAM).

BEIS-2 calculates VOC from vegetation and NOx from soils. Emissions from vegetation are calculated using vegetation types divided into 75 tree genera, 17 agricultural crops, and urban grasses. BEIS-2 calculates three groups of VOC emissions: isoprene, monoterpenes, and other NMHCs for the tree genera types, agricultural crops, and urban grasses (Pierce, 1994a).

Further carbon bond speciation can be done through air quality model speciation routines, such as the UAM Emission Preprocessor System (EPS) (EPA, 1990b). The more robust versions of the BEIS-2, those used for air quality modeling, provide a file of gridded hourly data, which can be converted to input for the particular air quality model for which it was prepared.

Soil emissions of NOx are dependant on the crop type and fertilization rate (EPA, 1993), and on a multitude of other factors. BEIS-2 calculates emissions of NOx as NO based on crop type and fertilizer use. Emission factors have also been updated in BEIS-2. The Biogenic Emissions Inventory System version 2 (BEIS-2) is a system that produces hourly biogenic emission estimates for use in photochemical modeling.

Output files are at a level of detail suitable for use in State Inventory Plans (SIPs) and input into the air quality model EKMA. In addition to these primary uses, PCBEIS2.3 can be used for any application where biogenic VOC and NOx emission estimates at this level of detail are needed.

The BEIS2 originator was Thomas E Pierce (email: pierce.tom@epa.gov) Atmospheric Modeling Division US Environmental Protection Agency (MD-80) Research Triangle Park, NC 277111 BEIS2.3 programmer: Steve Howard Atmospheric Modeling Division US Environmental Protection Agency (MD-80) Research Triangle Park, NC 27711

Biogenic Emissions Inventory System, Version 2.3 was released on 30 November 1998. BEIS2.3 is especially suited for users unable to run BEIS2. Because BEIS2 was written in DOS FORTRAN, many users were unable to use the full-screen menu options contained in BEIS2. BEIS2.3 has been written in C++/JAVA to allow better operability with current PC operating systems and to take advantage of more recent approaches in object-oriented programming. BEIS2.3 uses the same emission factors and land use data as BEIS2 and should produce very similar results. This version of BEIS is simply a reprogrammed version of BEIS2. A formalized version of BEIS3 is expected late in 1999.

 

PROCESSING METHODOLOGY

Modeling Day Selection

Modeling day selection is at least partly determined by the intended application of the results, or the reason for the emission estimate. A SIP base year inventory may need a total biogenic VOC estimate for a single typical ozone day. The day selection procedure below describes the steps in selecting such a day for use in the PCBEIS2.3. If results from PCBEIS2.3 are intended for use with an air quality model such as EKMA, a number of days will need to be simulated with PCBEIS2.3. These will correspond to the days which will be modeled.

Assumptions

Using an approach approved verbally by Mark Estes, a meteorologist employed by the TNRCC on October 15, 1999, we have selected an average hypothetical summer day for the development of this model. The two variables we have supplied in the development of this model are temperature and incident solar radiation.

The average temperatures for July, using the average daily high and average daily low for the month of July over a 30-year period (1961-1990) were used. It was assumed that the low temperature for the day was encountered at 6:00 am and that the average high temperature for the day was at 16:00 (4:00 p.m.). It was further assumed that the temperature rose and fell each day in a linear fashion from low to high and then back to low on the following morning. More detailed climate information may be obtained from the National Climate Data Center, Asheville, North Carolina. Telephone Number 1-704-271-4800. Internet: http://www.ncdc.noaa.gov

The model requires a specific day for solar radiation to calculate emission rates. The average solar radiation over the course of the summer would fall on about July 30, or equidistant between the summer solstice and the vernal equinox. For this reason, July 30 was chosen as an average summer day. Once the county and day of the year are selected, the incident Solar Radiation is automatically provided by this program. We have assumed the normally accepted value of zero cloud cover.

An alternative procedure for selecting a typical ozone day has been described by one source attempting to establish a model for a day with an assumed high ozone value. This alternative approach would involve selecting the day with the fourth-highest temperature out of the ten highest ozone days from a 3-year period from 1987 to 1989. While this may be applicable for estimating biogenic emissions during extremely poor temperature, wind, or sunlight conditions, it would not represent an average summer day.

Results

The following table has been provided to indicate the total volatile organic compound (VOC) and oxides of nitrogen (NOx) emissions for counties in the AACOG Region. (NOx) emissions for counties in the AACOG Region are not represented here due to the fact that they were calculated for in the agricultural fertilizer section of the area source category of the inventory.

AACOG 12 County Region Biogenic Emissions

Biogenic Emissions	VOC ton/day	NOx ton/day	CO ton/day
Atascosa County	16.000	0	0
Bandera County	22.117	0	0
Bexar County	41.521	0	0
Comal County	36.499	0	0
Frio County	17.629	0	0
Gillespie County	11.382	0	0
Guadalupe County	26.433	0	0
Karnes County	6.783	0	0
Kendall County	10.575	0	0
Kerr County	21.083	0	0
Medina County	21.578	0	0
Wilson County	6.415	0	0
TOTAL	238.015	0	0

 

REFERENCES AND BIBLIOGRAPHY

REFERENCES

Birth, T.L. 1995. User's Guide to the Personal Computer Version of the Biogenic Emissions Inventory System (PCBEIS2.3). Prepared for U.S. Environmental Protection Agency, Office of Research and Development. Washington, D.C.

Borucki, W.J., and W.L. Chameides. 1984. Lightning: Estimates of the Rates of Energy Dissipation and Nitrogen Fixation. Reviews of Geophysics and Space Physics, vol. 22, no 4, pp. 363-372.

Brandvold, D.K., and P. Martinez. 1988. The NOx /N2O Fixation Ratio from Electrical Discharges. Atmospheric Environment, vol. 22, no. 11, pp. 2477-2480. California Air Resources Board. 1993. Emission Methodology for Oil and Gas Seeps.

Chameides, W., R. Lindsay, J. Richardson, and C. Kiang. 1988. The Role of Biogenic Hydrocarbons in Urban Photochemical Smog: Atlanta as a Case Study. Science, vol. 241, pp. 1473-1475.

Cheung, I., B. Lamb and H. Westburg. 1991. Uncertainties in a Biogenic Emissions Model: Use of Satellite Data to Derive Land Use and Biomass Density Data. Presented at the AWMA International Specialty Conference on Emission Issues of the 1990's, Durham, North Carolina.

EPA. 1994. Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-1993. U. S. Environmental Protection Agency/Office of Policy, Planning and Evaluation, EPA 230-R-94-014. Washington, D.C.

EPA. 1993. Air Quality Criteria for NOx , Volume I. U. S. Environmental Protection Agency, EPA 600/8-91/049aF. Research Triangle Park, North Carolina.

EPA. 1991a. Procedures for the Preparation of Emissions Inventories for CO and Precursors of Ozone, Volume I: General Guidance for Stationary Sources. U. S. Environmental Protection Agency/Office of Air Quality Planning and Standards, 450/4-91-016. Research Triangle Park, North Carolina. EIIP Volume V 6-1.Biogenic Sources 5/21/96

EPA. 1991b. Procedures for the Preparation of Emissions Inventories for CO and Precursors of Ozone, Volume II: Emission Inventory Requirements for Photochemical Air Quality Simulation. U. S. Environmental Protection Agency/Office of Air Quality Planning and Standards, 450/4-91-014. Research Triangle Park, North Carolina.

EPA. 1990a. Literature Review of Greenhouse Gas Emissions from Biogenic Sources. Office of Research and Development/Air Energy Engineering Research Laboratory, 600/68-90/017. Research Triangle Park, North Carolina.

EPA. 1990b. User's Guide for the Urban Airshed Model, Volume IV: User's Manual for the Emissions Preprocessor System 2.0, Part A: Core FORTRAN System, EPA-450/4-90-007D(R) (NTIS PB93-122380/XPB). U. S. Environmental Protection Agency, Research Triangle Park, North Carolina.

Gaudioso, D., and M. C. Cirillo. 1993. Uncertainty of NMVOC Emission Estimates from Vegetation. Presented at the EPA/AWMA International Specialty Conference on Emission Inventory Issues in the 1990's, Durham, North Carolina.

Geron, C. D., U. S. Environmental Protection Agency, Air Energy Engineering Research Laboratory with D. L. Jones and L. H. Adams, Radian Corporation. April 9, 1994. Contact Report.

Geron, C. D., A. B. Guenther, and T.E. Pierce. 1994. An Improved Model for Estimating Emissions of Volatile Organic Compounds from Forests in the Eastern United States. Journal of Geophysical Research (Atmospheres), vol. 99, pp. 12,773-12,791.

Geron, C. D., T. E. Pierce, and T. L. Birth. 1992. An Alternative Method for Estimating Biogenic VOC Emissions in EPA Region I. Presented at the EPA/AWMA International Specialty Conference on Emission Inventory Issues in the 1990's, Durham, North Carolina.

Guenther, A. B., P. R. Zimmerman, and M. Wildermuth. 1994. Natural Volatile Organic Compound Emission Rate Estimates for U. S. Forest and Woodland Landscapes. Atmospheric Environment, vol. 28, pp. 1197-1210.

Guenther, A., P. Zimmerman, P. Haley, R. Monson, and R. Fall. 1993. Isoprene and Monoterpene Emission Rate Variability: Model Evaluations and Sensitivity Analysis. Journal of Geophysical Research, vol. 98, no. D7, pp. 12,609-12,617. EIIP Volume V 6-2.5/21/96 Biogenic Sources

Hill, R.D., R.G. Rinker, and A. Coucouvinos. 1984. Nitrous Oxide Production by Lightning. Journal of Geophysical Research, vol. 89, no. D1, pp. 1411-1421. Johansson, C., H. Rodhe, and E. Sanhueza. 1988. Emission of NO from Savannah Soils during Rainy Season. Journal of Geophysical Research, vol. 93, pp. 14,193-14,198.

Lamb B., D. Gay, H. Westberg, and T. Pierce. 1993. A Biogenic Hydrocarbon Emission Inventory for the U.S.A. Using a Simple Forest Canopy Model. Atmospheric Environment, vol. 27A, pp. 1673-1690.

Levine, J.S., T.R. Augustsson, I.C. Anderson, J.M. Hoell, and D.A. Brewer. 1984. Tropospheric Sources of NOx : Lighting and Biology. Atmospheric Environment, vol. 18, no. 9, pp. 1797-1804.

Logan, J.A. 1983. Nitrogen Oxides in the Troposphere: Global and Regional Budgets. Journal of Geophysical Research, vol. 88. no. C15, pp. 10,785-10,807.

Loveland, T.R., J.W. Merchant, D.O. Ohlen and J.F. Brown. 1991. Development of a Land-Cover Characteristics Database for the Conterminous U.S. Photogrammetric Engineering & Remote Sensing, vol. 57, no. 11, pp. 1453-1463.

Mayenkar, K.K. 1993. Development of Biogenic Emissions for the Southeast Michigan State Implementation Plan (SIP) Inventory. Radian Corporation, Sacramento, CA, March 1993.

Nekton, Inc. 1982. A Manned Submersible Survey of Three Areas of Natural Oil and Gas Seeps in State Coastal Waters in the Santa Barbara Channel. Prepared for the California State Lands Commission, January 1982.

Nowak, D.J. 1991. Urban Forest Development and Structure: Analysis of Oakland, California. PhD dissertation in Wildlife Resource Science, University of California at Berkeley.

Novak, J.H., and T. E. Pierce. 1993. Natural Emissions of Oxidant Precursors. Water, Air, and Soil Pollution, vol. 67, pp. 57-77.

Noxon, J.F. 1976. Atmospheric Nitrogen Fixation by Lightning. Geophysical Research Letters, vol. 3, pp. 463-465. EIIP Volume V 6-3.Biogenic Sources 5/21/96

Olson, R., C. Emerson, and M. Nunsgesser. 1980. Geoecology: A County-Level Environmental Data Base for the Conterminous United States, ORNL/TM-7351, Oak Ridge National Laboratory, Oak Ridge, TN.

Orville, R., R. Henderson, and L. Bosart. 1983. An East Coast Lightning Detection Network. Bulletin of the American Meteorological Society, vol. 64, pp. 1,024.

Pierce, T.E. U. S. Environmental Protection Agency, Air Research and Exposure Assessment Laboratory with L. H. Adams, Radian Corporation. April 9, 1994a. Personal Communication.

Pierce, T.E. U.S. Environmental Protection Agency, Air Research and Exposure Assessment Laboratory with L. H. Adams, Radian Corporation. November 28, 1994b. Personal Communication.

Pierce, T.E., and A. R. Van Meter. October 1992. Volatile Organic Compound and Nitric Oxide Emissions from Corn in the Midwestern United States. Presented at the EPA/AWMA International Specialty Conference on Emission Inventory Issues in the 1990's, Durham, NC.

Pierce, T.E. and J.H. Novak. 1991. Estimating Natural Emissions for EPA's Regional Oxidant Model. Presented at the EPA/AWMA International Specialty Conference on Emission Inventory Issues in the 1990's, Durham, N.C.

Radian Corporation and Valley Research Corporation. 1993. Texas Natural Resource Conservation Commission Biogenic Emission Factors Project, project report. Prepared for the Texas Natural Resource Conservation Commission.

Williams, E.J., A. Guenther, and F.C. Fehsenfeld. 1992. An Inventory of Nitric Oxide Emissions from Soils in the United States. Journal of Geophysical Research, vol. 97, no. D7, pp. 7511-7519.

Yienger, J.J., and H. Levy II. 1995. Empirical Model of Global Soil-Biogenic NOx Emissions. Journal of Geophysical Research, vol. 100, no. D6, pp. 11,447-11,464.

Zuidema, G., Van Den Born, J. Alcamo, and G.J.J. Kreileman. 1994. Simulating Changes in Global Land Cover as Affected by Economic and Climatic Factors. Water, Air and Soil Pollution, vol. 76, pp. 163-198.

EIIP Volume V 6-4.5/21/96 Biogenic Sources

 

BIBLIOGRAPHY

Anderson, I.C., and J.S. Levine. 1986. Relative Rates of Nitric Oxide and Nitrous Oxide Production by Nitrifiers, Denitrifiers, and Nitrate Respirers. Applied and Environmental Microbiology, May 1986, pp. 938-945

Winer, A.M., D.R. Fitz, and P.R. Miller. 1983. Investigation of the Role of Natural Hydrocarbons in Photochemical Smog Formation in California, Final Report. Statewide Air Pollution Research Center, University of California, report no. PB84- 108653. Prepared for California Air Resources Board.

Causley, M.C., and G.M. Wilson. 1991. Seasonal and Annual Average Biogenic Emissions for the South Coast Air Basin Generated by the SCAQMD Biogenic Data Base System. Prepared for South Coast Air Quality Management District.

Horie, Y., S. Sidawi, and R. Ellefsen. 1990. Inventory of Leaf Biomass for Vegetation in California's South Coast Air Basin. Prepared for South Coast Air Quality Management District.

Nowak, D.J. 1994. Urban Forest Structure: The State of Chicago's Urban Forest.In Chicago's Urban Forest Ecosystem: Results of the Chicago Urban Forest Climate Project, prepared by Northeastern Forest Experiment Station, General Technical Report NE-186, U.S. Dept. of Agriculture. E.G. Mcpherson, D. J. Nowak, R. A. Rowntree, eds.

Noxon, J.F. 1976. Atmospheric Nitrogen Fixation by Lightning. Geophysical Research Letters, vol. 3, no.8, pp. 463-465. EIIP Volume V 6-5.Biogenic Sources 5/21/96

 

Electronic sources

¹ BEIS2 User's Guides Environmental Protection Agency. 1995. - http://www.epa.gov/ttn/scram/t23.htm, 95 Policy

 

Back to the Table of Contents.