FLAGFLAGDeposition Subgroup ReportDeposition Subgroup Report

Ellen PorterEllen Porter

Air Quality BranchAir Quality Branch

U.S. Fish and Wildlife ServiceU.S. Fish and Wildlife Service

Deposition SubgroupDeposition Subgroup

Included scientists and air quality Included scientists and air quality specialists from FWS, NPS, and specialists from FWS, NPS, and USDA-FSUSDA-FS

Report reviewed by deposition Report reviewed by deposition experts, both inside and outside of experts, both inside and outside of governmentgovernment

Subgroup focused on Subgroup focused on deposition of:deposition of:

Sulfur (sulfate)Sulfur (sulfate) Nitrogen (nitrate, ammonium ion, Nitrogen (nitrate, ammonium ion,

nitric acid)nitric acid)

FLAG Phase IFLAG Phase I

Summarization of currently available Summarization of currently available information on deposition and its effects information on deposition and its effects on FLM areason FLM areas

Recommendations for modeling and Recommendations for modeling and evaluating current and future deposition evaluating current and future deposition and its effects on AQRVsand its effects on AQRVs

Identification of information on critical Identification of information on critical loads and other levels of concern for loads and other levels of concern for AQRVsAQRVs

FLAG Phase IIFLAG Phase II Develop methods for establishing critical Develop methods for establishing critical

deposition loading values and levels of deposition loading values and levels of concern for FLM areasconcern for FLM areas

Obtain additional information on deposition Obtain additional information on deposition and deposition effects in FLM areasand deposition effects in FLM areas

Review previously established critical Review previously established critical loads and levels of concernloads and levels of concern

Provide research and monitoring Provide research and monitoring recommendationsrecommendations

Ecosystem Effects of Ecosystem Effects of Sulfur and Nitrogen DepositionSulfur and Nitrogen Deposition

Acidification of lakes, streams, and Acidification of lakes, streams, and soilssoils

Leaching of nutrients from soilsLeaching of nutrients from soils Injury to high-elevation spruce forestsInjury to high-elevation spruce forests Changes in nutrient cyclingChanges in nutrient cycling Fertilization of terrestrial ecosystemsFertilization of terrestrial ecosystems Eutrophication of estuarine and N-Eutrophication of estuarine and N-

limited freshwater systemslimited freshwater systems

ECOSYSTEM INDICATORS FOR SULFUR DEPOSITION

Freshwater Chemical change (ANC depression),changes in phytoplankton andbenthic community composition,species diversity, biomass

Terrestrial Leaching of soil cations, soilacidification, mobilization ofaluminum ions

Estuarine Saltwater not sensitive to Sdeposition; leaching of nutrientsmay occur in sandy nearshore soils

ECOSYSTEM INDICATORS FOR NITROGEN DEPOSITION

Freshwater Chemical change (ANC depression),changes in phytoplankton andbenthic community composition,species diversity, biomass

Terrestrial Changes in: litter and soil carbonand N dynamics; biomass; soil Nprocesses; litter decompositionrates; soil microbe functionalgroups soil organic matter qualityand quantity; soilwater chemistry

Estuarine Changes in: phytoplankton speciescomposition and biomass; aquaticinvertebrates; seagrass health anddistribution; nutrient ratios;dissolved oxygen; trophic status

Critical LoadCritical Load: The concentration of air pollution above : The concentration of air pollution above which a specific deleterious effect may occur.which a specific deleterious effect may occur.

Concern threshold: An adverse impact threshold or other quantifiable level in resource condition or pollutant exposure identified by the FLM.

FLMs agree that a critical load or concern threshold value FLMs agree that a critical load or concern threshold value should:should:– protect the most sensitive AQRVs within each FLM areaprotect the most sensitive AQRVs within each FLM area– be based on the best science availablebe based on the best science available– ensure that no unacceptable change occurs to the ensure that no unacceptable change occurs to the

resourceresource

Approaches to Establishing Approaches to Establishing Critical LoadsCritical Loads

National and regional workshopsNational and regional workshops Regional reviewsRegional reviews Site-specific studiesSite-specific studies

Recommendations and Guidance for Recommendations and Guidance for Evaluation Potential Effects from Evaluation Potential Effects from

Increased DepositionIncreased Deposition Includes:Includes:

– the types of data, information, and analysis the types of data, information, and analysis needed before a permit is considered completeneeded before a permit is considered complete

– approaches and appropriate values for approaches and appropriate values for estimating wet and dry depositionestimating wet and dry deposition

– mitigation strategiesmitigation strategies

NOTENOTE: Applicant should consult with FLM : Applicant should consult with FLM to determine if a deposition impact analysis to determine if a deposition impact analysis should be doneshould be done

Are there current adverse effects to Are there current adverse effects to AQRVs from deposition?AQRVs from deposition?

Is the critical load exceeded?Is the critical load exceeded?

If “yes,” FLM may recommendIf “yes,” FLM may recommend

• stricter (than BACT) controlsstricter (than BACT) controls

• emissions offsetsemissions offsets

• identification of sources contributing identification of sources contributing to adverse effects; SIP revision to to adverse effects; SIP revision to reduce emissions from these sourcesreduce emissions from these sources

• deposition and deposition effects deposition and deposition effects monitoring/research in the FLM areamonitoring/research in the FLM area

• denial of permitdenial of permit

Are there current adverse effects to Are there current adverse effects to AQRVs from deposition?AQRVs from deposition?

Is the critical load exceeded?Is the critical load exceeded?

If “no” or “unknown,” the FLM will ask:If “no” or “unknown,” the FLM will ask:– will the new emissions cause or will the new emissions cause or

contribute to adverse effects or an contribute to adverse effects or an exceedance of the critical load?exceedance of the critical load?

Will the new emissions cause or Will the new emissions cause or contribute to adverse effects or an contribute to adverse effects or an

exceedance of the critical load?exceedance of the critical load?

– If “yes,” FLM may recommendIf “yes,” FLM may recommend• stricter (than BACT) controlsstricter (than BACT) controls• emissions offsetsemissions offsets• identification of sources contributing to adverse identification of sources contributing to adverse

effects; SIP revision to reduce emissions from these effects; SIP revision to reduce emissions from these sourcessources

• deposition and deposition effects monitoring/research deposition and deposition effects monitoring/research in the FLM areain the FLM area

• denial of permitdenial of permit– If “no,” FLM is unlikely to object to permit on basis of If “no,” FLM is unlikely to object to permit on basis of

deposition effectsdeposition effects– If “unknown,” FLM may recommend monitoring/research If “unknown,” FLM may recommend monitoring/research

in the FLM areain the FLM area

Information needed by FLM Information needed by FLM and applicantand applicant

Deposition-sensitive AQRVsDeposition-sensitive AQRVs Critical loads or levels of concernCritical loads or levels of concern Current and future pollutant Current and future pollutant

deposition rates in FLM areadeposition rates in FLM area

Deposition-sensitive AQRVs,Deposition-sensitive AQRVs,Critical loads/Levels of ConcernCritical loads/Levels of Concern

Identified by FLMsIdentified by FLMs Information on many USDA-FS areas now Information on many USDA-FS areas now

on web; info on NPS and FWS areas on web on web; info on NPS and FWS areas on web in futurein future

Web-based information can be updated as Web-based information can be updated as neededneeded

NOTENOTE: Applicants should contact : Applicants should contact appropriate FLM before conducting analysesappropriate FLM before conducting analyses

Web InformationWeb InformationExamples:Examples: USDA-FS information at USDA-FS information at www.fs.fed.us/r6/aq/natarmwww.fs.fed.us/r6/aq/natarm

– Mt. Zirkel Wilderness (CO)Mt. Zirkel Wilderness (CO)• Concern thresholds for lakes with low ANC:Concern thresholds for lakes with low ANC:

– ANC change of > 1ueq/l, or ANC change of > 1ueq/l, or – > 10% change in ANC over baseline> 10% change in ANC over baseline

NPS web page under developmentNPS web page under development– Mt. Rainier NPMt. Rainier NP

• Critical loads for lakes:Critical loads for lakes:– total sulfur: 3 kgS/ha/yrtotal sulfur: 3 kgS/ha/yr– total nitrogen: 5 kgN/ha/yrtotal nitrogen: 5 kgN/ha/yr

Current Deposition Rates Current Deposition Rates in FLM Areasin FLM Areas

See Table D-2 in Subgroup ReportSee Table D-2 in Subgroup Report– Wet deposition: NADP data (on web)Wet deposition: NADP data (on web)– Dry deposition: CASTNet data (on web) or Dry deposition: CASTNet data (on web) or

assume “dry=wet”assume “dry=wet”

NOTENOTE: Applicants should contact : Applicants should contact appropriate FLM before conducting appropriate FLM before conducting analysesanalyses

Future Deposition Rates Future Deposition Rates in FLM Areasin FLM Areas

Contributions from proposed source and Contributions from proposed source and sources permitted but not yet operating must sources permitted but not yet operating must be modeled in accordance with IWAQM be modeled in accordance with IWAQM recommendationsrecommendations

Future Deposition = Current + Proposed + Future Deposition = Current + Proposed + Permitted (not yet operating)Permitted (not yet operating)

NOTENOTE: Applicants should contact appropriate : Applicants should contact appropriate FLM before conducting analysesFLM before conducting analyses